Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Anatomy of the Abdomen and pelvis 03 May 2012 08:48 Guide for use of these notes First of all thank you for choosing to download these notes to study from I hope you find them useful, please feel free to email me if you have any problems with the notes or if you notice any errors. I don't promise to respond to all emails but I'll do my best. For the Anatomy of The Abdomen and Pelvis notes I used a mixture of Gray's, Netter's and Clinically Orientated Anatomy. In addition some detail is taken from Instant Anatomy for android written by Dr. Robert Whitaker who teaches anatomy at Cambridge. I organise my notes so that you should read the learning objectives on the left then proceed down the right hand side for a few learning objectives and then cross back over to the left and continue like that. Anything in this highlighted green is a definition or explains basically something's function. Text highlighted in yellow or with a star is what I would deem important and key to your learning. Italics and bold just help to make certain terms stand out. The notes are a bit quirky but I hope you like them and find some of the memory aides strange enough so that they stick in your head. I provide them to you in OneNote format as that is how I created them, they can be saved as PDF but the formatting is not as nice. The one caveat with this is that these notes are freely copy able and editable. I would prefer if you didn't copy and paste my notes into your own but used them as a reference or preferably instead embellished these already existing notes by adding to them. Good luck with first year Stuart Taylor Stuart's Anatomy of the Abdomen and Pelvis Page 1 Abdominal wall, inguinal region and hernias 03 May 2012 08:58 Describe the rectus sheath and its contents. Define the linea alba and the linea semilunaris Demonstrate in the living subject and in dissected material the nature and course of the inguinal canal making correct use of the following terms: superficial and deep inguinal rings, mid-inguinal point, pubic tubercle, testis, testicular vessels, scrotum, spermatic cord, ductus deferens, round ligament of the uterus. Distinguish between direct and indirect inguinal hernias. Distinguish between acquired and congenital inguinal hernia Summarise the anatomical basis for femoral hernia. Explain the importance of the distinction between the fatty and membranous layers of the superficial fascia Describe the rectus sheath and its contents. 3 levels • Above costal margin • Between costal margin and arcuate line • Below arcuate line • Arises from costal cartilages 5-7 and the xiphoid process and descends lateral to the linear alba to insert on the pubic crest and the front of the pubic symphysis. • Divided into segments by transverse tendinous intersections General information on hernias • Hernia- A protrusion of a viscus through a defect in its containing compartment such that it lies in an abnormal position. • Reducible- sac returns to containing cavity • Irreducible- sac cannot be returned to containing cavity • Obstructed- sac contains blocked bowel • Strangulated- sac 's contents with strangulated blood supply • Children can be born with a defect in the groin. • 10x more common in males because of embryological descent of testes. Distinguish between direct and indirect inguinal hernias. Indirect • This is the most common type • Tend to be in younger adults and children • Due to lax deep ring or patent processus vaginalis. • More common on the right hand side. • The deep ring is too large, peritoneum pushes through. • Indirect hernia defect is always the deep/internal ring which is always LATERAL to the inferior epigastric vessels. Direct • Groin hernias that occur in old people. • Acquired defect in posterior wall of the inguinal canal. • Associated with chronic straining. • A direct hernia defect tends to go through Hesselbach's triangle, which is always MEDIAL to the inferior epigastric vessels. Medial Lateral • Rectus abdominis lies deep to the aponeurosis of the external oblique throughout its length. • In the upper two-thirds of the anterior abdominal wall it lies anterior to the transversus abdominis aponeurosis while the internal oblique aponeurosis splits to enclose it. • Rectus abdominis therefore lies in a fibrous tunnel called the rectus sheath. The anterior wall of the sheath consists of the aponeurosis of external oblique fused with the anterior leaf of the internal oblique aponeurosis. Similarly the posterior wall comprises the posterior leaf fused with the transversus abdominis aponeurosis. • In the lower part of the sheath, all the aponeuroses pass anterior to rectus so that this part is ‘backless’. • The free lower posterior margin of the posterior layer of the rectus sheath is known as the arcuate line. Define the linea alba and the linea semilunaris • At the lateral margin of the rectus abdominis the aponeuroses of the three flat muscles fuse to form the linea semilunaris before enclosing the rectus muscle and fusing again in the midline at the linea alba. Contents: Inferior epigastric Vessels Hesselbach’s Triangle • Arteries and veins lying posterior to the muscle. These are the epigastric vessels. • There is an anastomosis between the superior epigastric artery, which is a branch of the internal thoracic, and the inferior epigastric, which forms an interesting though relatively useless bypass of the abdominal and descending aortas. • Nerve supply to the muscles are from T6-L1 • Intercostal nerves are from T6-T12 and the main trunks of these lie between the Internal oblique and Transversus abdominis layers (like the intercostal nerves in the chest wall) Arrangement of the sheet muscles Distinguish between acquired and congenital inguinal hernia • Most often occurs in male babies due to a patent processus vaginalis. • Processus is required for testicular descent and if it does not close properly the baby can get an indirect hernia. • Testes start out at the level of the kidneys which migrate to the scrotum. • They descend at the back of the abdomen. • There is a finger of peritoneum and the testes descend behind it which acts as a guide. • The finger of peritoneum is supposed to seal off which can be filled with bowel. Patent Processus Vaginalis The three sheet muscles, from superficial to deep, are: Stuart's Anatomy of the Abdomen and Pelvis Page 2 Patent Processus Vaginalis The three sheet muscles, from superficial to deep, are: External oblique • Slips off of ribs 5-12 and descends antero-inferiorly. Has an important free posterior border which runs from the anterior superior iliac spine (ASIS) to the pubic tubercle forming the inguinal ligament. NORMAL PATENT PROCESSUS Internal oblique • Originates from lumbar fascia, anterior 2/3 of iliac crest and lateral 2/3 of the inguinal ligament. • • • • • • • Factors associated with hernia Chronic cough-COPD, asthma Prostatic disease Constipation Muscular effort e.g. job Previous hernia repair Obesity Ascites • Highest ascend to ribs 10-12 lowest descend to the crest and medial part of pectineal line of the pubis. Transversus abdominis • Runs medially from the inner aspect of the costal margin from ribs 7-12, the lumbar fascia and from the anterior 2/3 of the iliac crest to the lateral 1/3 of the inguinal ligament. • Lowest fibres insert on the pubic crest and the pectineal line with the lower part of the internal oblique muscle as the conjoint tendon. Treatment is to stich or clip in a mesh of polyproponene low chance of recurrence is 1%. Distinguish between acquired and congenital inguinal hernia Summarise the anatomical basis for femoral hernia. • Femoral hernia protrudes through the femoral canal. • Very tight hole which is dangerous because it causes bowel to lose its blood supply. • Below and lateral to pubic tubercle is femoral above and medial is inguinal. Borders of the femoral canal Superior- Inguinal ligament Inferior- Pectineus fascia Medial- Lacunar ligament Lateral- Femoral vein The arrangement is homologous with the three layers of muscles found in the intercostal spaces. All three originate from the margins of the anterolateral wall, turn into aponeuroses (sheet-like tendons) in the anterior abdominal wall, and insert into a tough fibrous band called the linea alba (white line) that extends in the mid-line from the xiphoid process of the sternum to the pubic symphysis. Demonstrate in the living subject and in dissected material the nature and course of the inguinal canal making correct use of the following terms: superficial and deep inguinal rings, mid-inguinal point, pubic tubercle, testis, testicular vessels, scrotum, spermatic cord, ductus deferens, round ligament of the uterus. Inguinal canal • A canal formed by the layers of the abdominal wall muscle. • Approximately 4cm long. • It runs from the deep ring to the superficial ring. • Transmits the spermatic cord in the male and round ligament of the uterus in females. Also transmits into ilioinguinal nerve. ANTERIOR SUPERIOR ILIAC SPINE DEEP RING INGUINAL CANAL PUBIC TUBERCLE History • Lump in the groin • May come and go • There all the time • Painful • Vomiting/ constipation • Associated conditions. Deep ring- The deep (internal) ring is an opening in the back wall of the inguinal canal through which the canal's contents enter. Superficial ring- V shaped slit in the external oblique aponeurosis that allows the content of the canal to exit e.g. to the scrotum. Summary of the borders of the inguinal canal Anterior- External oblique aponeurosis + internal oblique Floor- Inguinal ligament Roof- Internal oblique arching over Posterior- Transversalis fascia and conjoint tendon medially (Transversalis is the same thing as transversus abdominis) • On examination femoral hernias tend to be irreducible, and hot and painful if strangulated. Stuart's Anatomy of the Abdomen and Pelvis Page 3 • On examination femoral hernias tend to be irreducible, and hot and painful if strangulated. • They can be distinguished from inguinal hernias because they appear below and lateral to the pubic tubercle. • Inguinal hernias are above and medial to the pubic tubercle. ANTERIOR SUPERIOR ILIAC SPINE PUBIC TUBERCLE FEMORAL HERNIA BELOW AND LATERAL TO PUBIC TUBERCLE Explain the importance of the distinction between the fatty and membranous layers of the superficial fascia • The superficial facia of the abdominal wall (subcutaneous tissue of the abdomen) is a layer of fatty connective tissue. It is usually a single layer similar to, and continuous with the superficial fascia throughout other regions of the body. However in the lower region of the anterior part of the abdominal wall, below the umbilicus, it forms two layers: a superficial fatty layer and a deeper membranous layer. Superficial fatty layer • This layer contains fat and varies in thickness. It is also known as Camper's fascia. • It is continuous over the inguinal ligament with the superficial fascia of the thigh and with a similar layer in the perineum. • In men, this superficial layer continues over the penis and, after losing its fat and fusing with the deeper layer of superficial fascia, continues into the scrotum where it forms a specialised fascial layer containing smooth muscle fibres (the dartos fascia). In women, this superficial layer retains some fat and is a component of the labia mayor. Deeper Layer • The deeper membranous layer of superficial fascia (Scarpa's fascia) is thin and membranous, and contains little or no fat. Inferiorly, it continues into the thigh, but just below the inguinal ligament, it fuses with the deep fascia of the thigh. • In the mid-line, it is firmly attached to the linea alba and the symphysis pubis. It continues into the anterior part of the perineum where it is firmly attached to the isciopubic rami and to the posterior margin of the perineal membrane. Here, it is referred to as the superficial perineal fascia (Colles' fascia) • In men, the deeper membranous layer of superficial fascia blends with the superficial layer as they both pass over the penis, forming the superficial fascia of the penis, before they continue into the scrotum where they form the dartos fascia. • Also in men, extensions of the deeper membranous layer of superficial fascia attached to the pubic symphysis pass inferiorly onto the dorsum and sides of the penis to form the fundiform ligament of penis. • In women, the membranous layer of the superficial fascia continues into the labia majora and the anterior part of the perineum Stuart's Anatomy of the Abdomen and Pelvis Page 4 Living Anatomy 31 May 2012 12:34 Iliac tubercle is 5cm behind the Anterior Superior Iliac Spine Transpyloric plane is from the 9th costal cartilages across. Subcostal plane is the horizontal plane at level of costal margin in the Mid axillary line Transtubercular plane is the plane across the iliac tubercles. Supracrestal plane- Transverse plane running along the top of the iliac crests just below the umbilicus. Structure Vertebral level 1 Xiphisternum 2 Transpyloric plane T8/9 L1 3 Tip of 9th costal cartilage L1 4 Subcostal plane (Rib 10) 5 Umbilicus 6 Supracristal plane 7 Iliac tubercles L5 8 ASIS and PSIS/ Sacral Dimple S2 9 Midpoint of sacroiliac joint S2 L2 L3/4 L4 Structures at Transpyloric Plane: • L1 vertebrae • 9th CC • Origin of SMA • Formation of Portal Vein • Neck of the Pancreas • Hilum of the Kidney • Hilum of the Spleen • Duodenal-jejunal flexure • Pylorus • Transverse Colon • Fundus of gall bladder • End of spinal cord That’s 12 bitches. • Formed from the transtubercular plane, subcostal plane and two midclavicular vertical planes. Stuart's Anatomy of the Abdomen and Pelvis Page 5 Gut and Peritoneum 08 May 2012 09:00 Define parietal and visceral peritoneum and explain the functions of the peritoneum and peritoneal cavity Learning Objectives Define parietal and visceral peritoneum and explain the functions of the peritoneum and peritoneal cavity Draw diagrams to explain different relationships to the peritoneum (mesenteries and retroperitoneal positions) and list the structures contained within a typical mesentery Describe the peritoneal reflections in relation to major parts of the gut and associated organs from the oesophagus to the rectum, with special attention to the attachments and contents of the greater and lesser omenta and the mesentery proper • Normally elements of the gastrointestinal tract and its derivatives completely fill the abdominal cavity, making the peritoneal cavity a potential space, and visceral peritoneum on organs and parietal peritoneum in the adjacent abdominal wall slide freely against one another. • The peritoneum is a epithelial like single layer of cells (the mesothelium) together with a supportive layer of connective tissue. Peritoneum is similar to the pleura and serous pericardium in the thorax. • The peritoneum reflects off the abdominal wall to become a component of the mesenteries that suspend the viscera. • Components of the GI tract are suspended in peritoneal reflections called mesenteries. Describe the boundaries of the lesser sac and of the epiploic foramen (of Winslow) Parietal Peritoneum Name the regions of the gut from oesophagus to rectum and summarise their main functions Describe the sources and distribution of arteries to important structures or organs derived from the foregut, midgut and hindgut. Describe the peritoneal reflections in relation to major parts of the gut and associated organs from the oesophagus to the rectum, with special attention to the attachments and contents of the greater and lesser omenta and the mesentery proper Foregut- Distal 3rd of oesophagus to the 2nd part of the duodenum at the entrance of the bile duct (Major duodenal papilla) Midgut- 2nd part of the duodenum to two-thirds along transverse colon. Hindgut- Distal 3rd of transverse colon to the rectum. Visceral Peritoneum Mesentery Viscera e.g. Bowel Peritoneal Cavity • Parietal peritoneum lines the abdominal wall • Visceral peritoneum covers suspended organs. • • • • GI tract is suspended from the posterior/dorsal aspect. Peritoneal folds attaching viscera to the abdominal wall. Filled with peritoneal fluid secreted by the mesothelium. Epithelial layer secretes the fluid and circulates into the lymphatic vessels especially at the inferior surface of the diaphragm. Draw diagrams to explain different relationships to the peritoneum (mesenteries and retroperitoneal positions) and list the structures contained within a typical mesentery Intra vs. Retroperitoneal endoderm + 4 wk IUL • • • • • • Intraperitoneal- structures e.g. most of small intestine, suspended from the abdominal wall by mesenteries. • Retroperitoneal- structures e.g. kidneys and great vessels i.e. aorta and vena cava that lie between parietal peritoneum and posterior abdominal wall. Anterior/Ventral Endoderm, ectoderm and mesoderm. Yolk sac has no defined function The gut originates from the endoderm and splanchnic mesoderm. It is suspended from the posterior abdominal wall by a peritoneal fold- the dorsal mesentery. Blood supply, lymphatics and nerve supply all run through the mesentery. INTRAperitoneal RETROperitoneal Great Vessels • The entire gut tube is suspended from a dorsal mesentery. • In addition the foregut has a ventral mesentery. Ventral Kidneys Dorsal mesentery • The foregut has a ventral mesentery containing the liver, which splits into the falciform ligament and the lesser omentum. Formation of the Omental Bursa (Lesser sac) • Secondary fusion of the duodenum to the body wall, massive growth of the liver in the ventral mesentery, and fusion of the superior surface of the liver to the diaphragm restrict the opening to the space enclosed by the ballooned dorsal mesentery associated with the stomach. This restricted opening is the omental foramen (epiploic foramen) Retroperitoneal structures: Primary Suprarenal glands (the adrenals) Kidneys Ureter Bladder Aorta IVC Esophagus Rectum (part, lower 3rd is extraperitoneal Intraperitoneal organs • Stomach • 1st part of duodenum • Jejunum • Ileum • Cecum • Appendix • Transverse Colon • Sigmoid Colon • Rectum (Upper 1/3) • Liver Secondary * • Spleen • The head, neck, and body of the pancreas • Tail of pancreas but not the tail which is located in the splenorenal ligament. In women- Uterus, Fallopian Tubes, • Duodenum apart from the proximal Ovaries first segment which is intraperitoneal • • • • • • • • • Ascending and descending portions of colon (but not the transverse or cecum) • Good memory aide is SAD PUCKER. * These organs originally had a mesentery, then became secondarily retroperitoneal when the mesentery fused with the body wall. GI tract Basic Plan Stuart's Anatomy of the Abdomen and Pelvis Page 6 opening to the space enclosed by the ballooned dorsal mesentery associated with the stomach. This restricted opening is the omental foramen (epiploic foramen) the mesentery fused with the body wall. GI tract Basic Plan Mesentery Muscularis: Mucosa: Serosa: • The part of the abdominal cavity enclosed by the expanded dorsal mesentery, and posterior to the stomach, is the omental bursa (lesser sac). Access through the omental foramen to this space from the rest of peritoneal cavity (greater sac) is inferior to the free edge of the ventral mesentery. • Part of the dorsal mesentery that initially forms part of the lesser sac greatly enlarges in an inferior direction, and the two opposing surfaces of the mesentery fuse to form an apron like structure (the greater omentum). • The greater omentum is suspended from the greater curvature of the stomach, lines every other viscera in the abdominal cavity, and is the first structure observed when the abdominal cavity is opened anteriorly. • THE TWO GREATERS GO TOGETHER- GREATER OMENTUM AND GREATER CURVATURE • As the liver grows it moves to the right while the dorsal mesentery and spleen move to the left. The original right side of the upper peritoneal cavity is now posterior- the lesser sac of the peritoneal cavity. submucosa • Mucosa: Made up of epithelium Lamina propia Muscularis mucosae which is a layer of muscle needed to mobilise mucous. • Mesentery: Contains arteries and nerves that supply the tissue • Serosa: Areolar connective tissue Serosa is a connective tissue layer with epithelium which also lines the visceral peritoneum. • Muscularis: • Controlled by the autonomic nervous system. Contraction of two layers of muscle (circular and longitudinal) are needed to initiate peristalsis. Name the regions of the gut from oesophagus to rectum and summarise their main functions Oesophagus • Oesophagus pierces diaphragm at T10. • Pierces muscular part of diaphragm and contributes to Lower Oesophageal Sphincter which helps prevent gastro-oesophageal reflux. • Acts as a conduit for food and water which allows food to be digested in the stomach. Apparently this is a rage comic drawing of Nicholas Cage!!! Note this knowledge is not examinable unfortunately. Lower part of dorsal foregut mesentery extends down as a double fold called the greater omentum anterior to the intestine. The lesser omentum is part of the ventral foregut mesentery. Stomach • A ring of smooth muscle at distal end of Pyloric Canal prevents food entering duodenum. • Four main parts: a. Cardia surrounding the opening b. The fundus which is superior to cardia c. The body d. Pyloric region consisting of pyloric antrum and pyloric canal. • Sphincter controls flow of food into duodenum. Fundus Pyloric canal • Functions of greater omentum: i. Fat deposition, having varying amounts of adipose tissue ii. Immune contribution, having milky spots of macrophage collections iii. Infection and wound isolation; It may also physically limit the spread of intraperitoneal infections. The greater omentum can often be found wrapped around areas of infection and trauma. Describe the boundaries of the lesser sac and of the epiploic foramen (of Winslow) Stuart's Anatomy of the Abdomen and Pelvis Page 7 Pyloric antrum Body Duodenum • First part is more horizontal and is known as the duodenal cap and is where most duodenal ulcers occur. • Second part of duodenum contains entrance for common bile duct - Major Duodenal Papilla • Most of the duodenum is retroperitoneal. • 1-2 cm at beginning is intraperitoneal. 1 Describe the boundaries of the lesser sac and of the epiploic foramen (of Winslow) • Most of the duodenum is retroperitoneal. • 1-2 cm at beginning is intraperitoneal. 1 2 4 3 lesser omentum • The portal vein, hepatic artery and bile duct run between the posterior abdominal wall and liver within the lesser omentum near its free edge. This free edge is present because the ventral mesentery ends at the start of the midgut. 1 2 lesser sac 4 3 Jejunum Vs Ileum Jejunum Ileum Proximal 2/5 Distal 3/5 Larger in diameter Smaller in diameter Upper left quadrant of abdomen Lower right quadrant of abdomen greater sac Less prominent arterial arcades Prominent arterial arcades Longer vasa recta Shorter vasa recta. Large Intestine: Haustra pocketed walls) Epiploic foramen right The greater and lesser sacs of the peritoneal cavity communicate through a narrow opening called the epiploic foramen (entry to the lesser sac). This lies just below the liver, posterior to the free edge of the lesser omentum. • The lesser omentum (small omentum; gastrohepatic omentum; omentum minus) is the double layer of peritoneum that extends from the liver to the lesser curvature of the stomach and the start of the duodenum. • Lesser sac (Omental Bursa)- Is the cavity in the abdomen that is formed by the lesser and greater omentum. Usually found in mammals, it is connected with the greater sac via the epiploic foramen (also known as the Foramen of Winslow). ○ It is demarcated anteriorly by the caudate lobe of the liver, the stomach and lesser omentum. Posteriorly it is marked by the pancreas. Its left lateral margin is made by the left kidney and adrenal gland. Its boundary on the right is made by the epiploic foramen and lesser omentum. • Greater sac- This is the general cavity of the abdomen or peritoneal cavity. It is connected with the lesser sac via the omental foramen also known as the Foramen of Winslow or Epiploic Foramen. Describe the sources and distribution of arteries to important structures or organs derived from the foregut, midgut and hindgut. 3 unpaired arteries arising from the anterior of the aorta Stuart's Anatomy of the Abdomen and Pelvis Page 8 • Distinguishing features of large intestine from small intestine include fatty tags, (appendices epiploicae), ribbons of longitudinal muscle (taeniae coli) and segmented or pocketed walls. Diameter is not always a reliable guide. • Sigmoid colon is so named because it is S shaped. • Ileocecal orifice does not allow passage of waste back up- no defined sphincter arrangement although it does passively stop waste returning. • Transverse colon has a mesentery and therefore intraperitoneal with the sigmoid colon. Describe the sources and distribution of arteries to important structures or organs derived from the foregut, midgut and hindgut. 3 unpaired arteries arising from the anterior of the aorta • Coeliac trunk- Foregut, liver, pancreas and spleen. • Superior mesenteric artery (SMA)= Midgut • Inferior mesenteric artery (IMA)= Hindgut Venous return, lymphatics and nerve fibres Venous System • All veins drain back to the liver. • Liver will process the nutrients and pass them all back into the systemic circulation. • Portal vein= gut -> liver. Splenic v Portal vein Inferior mesenteric vein Superior mesenteric v • Splenic vein drains into the superior mesenteric which drains into the portal vein. • The portal vein arises from the superior mesenteric and splenic veins posterior to the 1st part of the duodenum/ pylorus of the stomach. It then runs in the free edge of the lesser omentum to the liver. Splenic v Portal vein Inferior mesenteric vein Superior mesenteric v Porto-systemic anastomoses • The portal systemic anastomoses are where veins draining to the portal vein and the IVC communicate. • Liver or portal obstruction causes these veins to dilate widely, possibly leading to severe haemorrhage from oesophagus or rectum. A • Inferior is the smallest one. Coeliac trunk • Supplies the entire foregut (lower oesophagus, stomach, upper duodenum) and its derivatives (liver and part of pancreas). The spleen, though not part of the alimentary system, develops close to the foregut and shares its blood supply from the coeliac trunk. C Coeliac trunk D SIPEE Common hepatic artery Stuart's Anatomy of the Abdomen and Pelvis Page 9 B trunk SIPEE Common hepatic artery B • The main branches of the Coeliac trunk are the Left Gastric Artery, Splenic Artery and the Common Hepatic Artery. • • • • Esophageal branches of left gastric - Esophageal branches of azygos vein. Superior Rectal- Inferior Rectal Paraumbilical -Epigastric Portal on left systemic on right. • Systemic circulation meets portal circulation. • Varicose veins on the wall of the gut can bleed easily if you cough hard enough. • This can happen if you are an alcoholic with an inflamed liver that diverts blood to other channels. • Portal hypertension. GI Overview Lymphatics: Lymphatics Thoracic duct Coeliac nodes Cisterna chyli Superior mesenteric nodes Coeliac trunk Superior Mesenteric Artery & vein • This block of structures forms the posterior relations of the liver and stomach and is part of the retroperitoneum. • The aorta bifurcates at the level of L3 into the inferior mesenteric and then at L4 to common iliac artery which means you cannot have an abdominal aortic aneurysm below the umbilicus which rules out one diagnosis. Superior Mesenteric Artery • Branches include: Middle colic artery Right colic artery Ileocolic artery Jejunal arteries Ileal arteries As in other parts of the body, the lymphatic drainage of the bowel follows the arterial supply, not the venous drainage. This is particularly important in the gut, where the two routes are very different. inferior mesenteric nodes Nerves: • Abdominal viscera is supplied by autonomic nervous system. • Sensory fibres most important. • Parasympathetic sensory (regulate reflex gut function) ○ Vagus Nerve ○ Pelvic Splanchnic Nerves (S2-S4) • Sympathetic sensory (mediate pain) ○ Thoracic splanchnic (T5-T12) ○ Lumbar splanchnic (L1+L2) Middle colic artery • Thoracic Splanchnic N. (T5-T12) Right colic artery • Greater Splanchnic N. (T5-T9) • Lesser Splanchnic N. (T10-T11) Jejunal arteries ileocolic artery Thoracic Splanchnic Ns. • Lumbar Splanchnic N. (L1 + L2) • Least Splanchnic N. (T12) Ileal arteries Inferior Mesenteric Artery • The junction of the mid and hind gut is near the left splenic flexure of the colon. There is a change from superior to inferior mesenteric artery supply at this level, but with anastomoses between them. Stuart's Anatomy of the Abdomen and Pelvis Page 10 • Innervation: the sensory fibres are most important. • In the viscera the sensory fibres running with the sympathetic (T1 -L2) mediate pain. • Sensory fibres running with the parasympathetic (vagus or sacral) are involved in reflex regulation of gut function. • LSS arteries-: Left colic artery Superior rectal artery Sigmoidal artery Stuart's Anatomy of the Abdomen and Pelvis Page 11 Liver, spleen and biliary system 15 May 2012 08:55 Learning Objectives Basic anatomy- Some detail is taken from Instant Anatomy for android written by Dr. Define the anatomical and functional lobes of the liver. Robert Whitaker who teaches anatomy at Cambridge Define the term “portal triad”. Know the names and contents of the mesenteries associated with the liver and spleen. Draw a basic diagram of the biliary tree. List the three major sites of porto-systemic anastomoses and their clinical pathology in portal hypertension. Know the anatomical relations of the liver and spleen. Define the anatomical and functional lobes of the liver. Anatomical- Divided into lobes by the falciform ligament Functional- Divided into lobes dependent on vascular supply to portal triads, also defined by the fossa for the gall bladder and the inferior vena cava. • Largest organ in the body that weighs 1500g and takes 30% of cardiac output. • Divided into two main lobes- use a line that goes through the falciform ligament (anatomical division of the liver). ○ The right lobe of the liver lies between ribs 6-10/costal cartilages. ○ Whereas the left lobe lies from 6-7 costal cartilages. Draw a basic diagram of the biliary tree. R L Falciform Lig. Common bile duct Ligamentum Teres Divided anatomically by the FALCIFORM LIGAMENT. • R lobe is larger than left. • Liver is enveloped by the ventral mesentery- LV- I LOVE THE LIVER. Define the term “portal triad”. • Common bile duct runs in free edge of the lesser omentum. • Bile duct is 8cm long and wide. • Ampulla of Vater opens into 2nd part of duodenum on posteromedual wall, 10cm from pylorus. Also known as the major duodenal papilla and marks the site of transition from foregut to midgut. • Number 3 is the sphincter of Oddi which controls the flow of pancreatic exocrine secretions through the ampulla of Vater. • Common bile duct lies in the lesser omentum. • Anteriorly joins liver and abdominal wall. • Posteriorly joins transverse colon and 1st part of duodenum. R hepatic duct Functional liver architecture • Liver can be divided functionally into segments supplied by portal triads and the fossa for gall bladder and IVC. • Line going through fossa of gall bladder and IVC. • The quadrate lobe is the weird bit on top. • Caudate lobe is the lobe in between. • Portal triad- Functional area of the liver containing a bile duct, hepatic artery and portal vein. Gallbladder Quadrate Lobe Anterior L hepatic duct Common hepatic duct R Pancreatic duct Cystic duct L Common bile duct Posterior Porta Hepatis Duodenum Spleen • • • • • • • • Lies behind the ribcage and cannot be felt unless it is grossly enlarged. Extremely vascular organ. 1 inches thick 3 inches wide 5 inches long Weighs 7oz Lies behind ribs 9-11 Quite a tense organ and therefore ruptures easily. IVC Caudate Lobe • Porta hepatis is the area on the under surface of the liver at which the structures in the • • • • free edge of the lesser omentum enter/leave the liver, (hilum of the liver) contains the, portal vein, hepatic artery and bile duct. Bare area of the liver- enlarges slightly out of the peritoneum directly in contact with the diaphragm. Be aware above that that is an inferior view I.e looking up at it from feet so bile duct and quadrate lobe are actually more inferior in a typical anterior view. The quadrate lobe is functionally part of the left lobe The caudate lobe is functionally independent of both lobes. Bare Area Diaphragm Subphrenic Recess Hepatorenal recess Stuart's Anatomy of the Abdomen and Pelvis Page 12 Subphrenic Recess Hepatorenal recess List the three major sites of porto-systemic anastomoses and their clinical pathology in portal hypertension. Posterior Anterior R. Kidney • Fibrotic liver disease- causes portal hypertension which means that when portal and systemic are joined, nutrients, bacteria etc will move to the systemic circulation without processing. Is bad! Tributaries to Azygos V. • Subphrenic and hepatorenal recesses created by foldings of peritoneum. Fluid in the abdomen will tend to collect in these areas because the patient is lying down. Know the vascular supply/drainage of the liver, spleen and gallbladder. Liver Left Gastric V. Paraumbilical Veins Superficial Veins on abdominal wall Sup. Rectal Vein. Blood supply Coeliac axis • Left gastric • Splenic • Common hepatic- runs with the bile duct and portal vein in the free edge of the lesser omentum. Branches are: ○ Cystic ○ Left hepatic ○ Right hepatic Internal Illiac Vs. R. Hepatic Inf. Rectal Vs. The Coeliac Axis Calot’s Triangle L Hepatic L. Hepatic 1. Paraumbilical veins- Superficial veins on abdominal veins. (They can become very dilated) Caput medusae. 2. Superior rectal veins- Inferior rectal veins- haemorrhoids development 3. Left gastric vein-tributaries of azygos vein- Clinically most important, bleeding oesophageal varices massive vomiting of blood- especially bad as they are likely to have liver disease therefore poor clotting factors. Left Gastric R Hepatic Common Hepatic Cystic L. Gastric Splenic Common Hepatic Splenic Know the names and contents of the mesenteries associated with the liver and spleen. • Mesentery- Two layers of peritoneum that are closely reflected to each other. • Conduit for arteries, veins, nerves and lymphatics supplying viscera. • Bag metaphor imagine pushing your hand into a bag but the outside. Ventral and Dorsal Mesenteries Aorta Cystic A. • Calot's triangle- Cholecystectomy- need to be careful when you clip off the artery that you do not clip off the common bile duct. Borders are: ○ Cystic duct ○ The common and right hepatic ducts ○ The inferior edge of the liver • Calot's triangle contains: ○ Cystic artery ○ Sometimes right hepatic artery ○ Calot's lymph node- enlarged in cholecystitis. Spleen • Ligament- Piece of peritoneum that attaches to viscera. • Lesser omentum= Gastric hepatic + hepato-duodenal ligaments. 1. Gastro-hepatic ○ Contains right and left gastric arteries. 2. Hepato-duodenal ligament ○ This contains the portal triad-portal vein, hepatic artery and bile duct. ○ Runs from 1st part of duodenum to liver. 3. Falciform ligament ○ Runs from liver to anterior abdominal wall 4. Ligament teres○ The free, thickened edge of the falciform ligament and contains the remnant of the umbilical vein which is now obliterated. 5. Gastro-splenic ligament (gastrolienal) ○ Contains short gastric vessels and left gastro-omental vessels. 6. Spleno-renal ligament ○ Contains tail of pancreas and splenic artery and vein. Splenic Artery • The splenic artery reaches the spleen by travelling in the spleno-renal ligament. Portal circulation Portal V. Anterior/Ventral Falciform Ligament Stuart's Anatomy of the Abdomen and Pelvis Page 13 Liver Splenic V. 6. Spleno-renal ligament ○ Contains tail of pancreas and splenic artery and vein. Portal circulation Portal V. Anterior/Ventral Splenic V. Falciform Ligament Liver Lesser Omentum - Gastrohepatic lig - Hepatoduodenal lig Stomach Gastrosplenic Ligament Spleen Sup. Mesenteric V. Inf. Mesenteric V. Splenorenal Ligament • The portal vein is formed from the Superior mesenteric vein and Splenic vein posterior to the neck of the pancreas at L2 level. • Filter bacteria from GI tract. • Metabolise all carbohydrates fats etc • Transport of amino acids straight to the brain causes dementia/encephalopathy due to ammonia. Kidneys Posterior/Dorsal Lesser omentum Portal V. Left Gastric V. Splenic V. Sup Mesenteric V. Inf Mesenteric V. CLOCKWISE rotation of the stomach along its longitudinal axis results in the right side of the peritoneal cavity becoming POSTERIOR – the OMENTAL BURSA (= LESSER SAC) ANTERIORLY (originally LEFT) is the GREATER SAC. • The lesser sac is in the posterior part of the peritoneal cavity and is directly in front of the retroperitoneal organs including the pancreas, great vessels, duodenum and kidneys. Lesser Omentum Lesser Omentum Lesser Curvature of Stomach Gallbladder Omental Foramen Stomach Duodenum • Free edge of lesser omentum contains: ○ Portal vein ○ Bile duct ○ Hepatic artery Stuart's Anatomy of the Abdomen and Pelvis Page 14 • Left gastric vein drains the fundus of the stomach. • Blood drains from the liver directly into IVC via 3 short hepatic veins. Retroperitoneum 15 May 2012 08:55 Learning Objectives Define the terms intraperitoneal, retroperitoneal and secondarily retroperitoneal. Define the terms intraperitoneal, retroperitoneal and secondarily retroperitoneal. Intraperitoneal- Structures suspended from abdominal wall by mesenteries (e.g. most of small bowel) Retroperitoneal- Structures lying posterior to parietal peritoneum (e.g. kidneys and great vessels) Secondary retroperitoneal- * These organs originally had a mesentery, then became secondarily retroperitoneal when the mesentery fused with the body wall. List the retroperitoneal organs. Demonstrate and name the major branches of the abdominal aorta Draw a basic diagram of the great vessels, kidneys, duodenum and pancreas. List the retroperitoneal organs. Name the major abdominal lymph nodes and outline their pattern of drainage. Demonstrate and name the major branches of the abdominal aorta • • • • • • • • Coeliac trunk-Supplies the Foregut Superior mesenteric artery- Supplies the Midgut Renal arteries- Kidneys Inferior mesenteric artery- Supplies the Hindgut Retroperitoneal structures: Primary Suprarenal glands (the adrenals) Kidneys Ureter Bladder Aorta IVC Esophagus Rectum (part, lower 3rd is extraperitoneal Secondary * • The head, neck, and body of the pancreas but not the tail which is located in the splenorenal ligament. • Duodenum apart from the proximal first segment which is intraperitoneal • Ascending and descending portions of colon (but not the transverse or cecum) Intraperitoneal organs • Stomach • 1st and 4th part of duodenum • Jejunum • Ileum • Cecum • Appendix • Transverse Colon • Sigmoid Colon • Rectum (Upper 1/3) • Liver • Spleen • Tail of pancreas In women- Uterus, Fallopian Tubes, Ovaries • Good memory aide is SAD PUCKER. • R Kidney Adrenal Glands L Kidney Pancreas Duodenum IVC Abdominal Aorta Ureters Foregut- Distal 3rd of oesophagus to the duodenum at the entrance of the bile duct ((Major duodenal papilla . Midgut- Major duodenal papilla to two-thirds along transverse colon. Hindgut- Distal third of transverse colon to the rectum. Veins are always anterior to arteries. Draw a basic diagram of the great vessels, kidneys, duodenum and pancreas. Coeliac Axis – L1 SMA – L1 Stuart's Anatomy of the Abdomen and Pelvis Page 15 Draw a basic diagram of the great vessels, kidneys, duodenum and pancreas. Pancreas Embryology • The pancreas develops as a ventral and dorsal bud in the ventral and dorsal foregut mesenteries respectively and therefore starts intraperitonealy. • The smaller ventral bud rotates clockwise to become dorsal and associated with the dorsal pancreatic bud. • Also the superior mesenteric vein becomes trapped between the two and the buds fuse to become secondary peritoneal, except for the tail which lies in the splenorenal ligament. The original ventral bud is now called the uncinate process. • Furthermore the embryology of the pancreas also explains why there is an accessory pancreatic duct in addition to the main one. SMA – L1 IMA – L3 Uncinate process Superior mesenteric V. Renal Vasculature IVC Superior mesenteric A. • Superior mesenteric vein and superior mesenteric artery are trapped between the uncinate process and the neck of the pancreas. Visceral relations of the Kidneys SMA R. Adrenal Gland L. Adrenal Gland Stomach Pancreas Liver Right Renal A. Spleen Splenic Flexure Left Renal A. Right Renal V. Left Renal V. 2nd part of duodenum Descending Colon Hepatic Flexure • Renal vessels arise at approximately L1- the transpyloric plane • Left renal vein is longer than right renal vein and runs posterior to SMA but anterior the left renal artery. Aneurysms of SMA cause nutcracker syndrome. ○ Note this is slightly weird because we usually say that veins lie anterior to arteries but this is a branch of the main aorta so that’s why it is ok for it to be weird and be posterior to the SMA. Duodenum Jejunum Name the major abdominal lymph nodes and outline their pattern of drainage. Sup. Mesenteric Nodes Coeliac Nodes Collectively = PARA-AORTIC NODES Lymphatic drainage follows the ARTERIES. Thoracic Duct Cisterna Chyli Coeliac Nodes Sup. Mesenteric Nodes Inf. Mesenteric Nodes • Note that tail of pancreas and the spleen are intraperitoneal structures. • Duodenal areas: i. Superior / first part – duodenal cap, common place for peptic ulcers. Passes anteriorly to bile duct, gastroduodenal artery, portal vein and IVC. ii. Descending / second part – contains minor and major duodenal papillae where accessory pancreatic duct and bile duct enter respectively. iii. Inferior / third – part – crosses IVC and has SMA anterior to it. iv. Ascending / fourth part – terminates at duodenojejunal flexure. Stuart's Anatomy of the Abdomen and Pelvis Page 16 Inf. Mesenteric Nodes • Onblock resection- Reduces rates of recurrence in malignancy. • Divisions of para-aortic nodes cannot be done accurately in vivo. • Cisterna Chyli is a dilated sac at the inferior end of the thoracic duct which empties into the junction of the left subclavian and left internal jugular veins in the thorax. Note the thoracic duct is found in the posterior mediastinum in the thorax and enters the abdomen through the aortic hiatus. Urinary System and Abdominal Ultrasound 17 May 2012 08:51 Learning Objectives Demonstrate and draw the principal relations of the duodenum, pancreas and kidneys including major vascular relations. Name the main organs in contact with each of the left and right kidneys Demonstrate and draw the principal relations of the duodenum, pancreas and kidneys including major vascular relations. Name the main organs in contact with each of the left and right kidneys Describe the arterial supply of the kidneys and adrenal (suprarenal) glands Describe the arterial supply of the kidneys and adrenal (suprarenal) glands Reminder- Retroperitoneal organs are- SADPUCKER Mark the likely positions of the kidneys and ureters in a living subject and demonstrate their positions in appropriate plain and contrast radiographs and in CT images. Demonstrate how to palpate the kidneys in a living subject. Demonstrate the main components of the posterior abdominal wall from diaphragm to pelvic inlet. Suprarenal glands, Aorta/IVC, Duodenum (not 1st part), Pancreas (all apart from tail) Urinary tract, Colon (descending + ascending), Kidneys, Esophagus, Rectum. Kidneys • Lie on posterior abdominal wall, adjacent and parallel to psoas muscle. • Left usually a little higher than right due to liver. • Approximately 10-12cm in size (3-4 lumbar vertebrae) • Surrounded by perinephric fat and renal fascia (Gerota's fascia)- open inferiorly. ○ Blood can go right down into the pelvis because of this. R. Adrenal Gland Imaging Modalities Plain abdominal X-Ray • Gas, fat, soft tissue and calcium/metal are the only 4 radiographic densities. • Renal and bladder outlines only visible because of surrounding fat. • Frequently obscured bowel gas. • Abdominal vessels not visible unless calcified. • Most renal and ureteric stones visible (85% calcified) Intravenous urogram/pyelogram • Control images essential • Iodine containing water soluble contrast given I.V • Filtered by the kidney into the collecting system. • Standard sequence of images taken. • Immediate-nephrogram phase- contrast in the glomeruli and proximal tubules. • • • • Delayed images- 5mins, 10mins, 15mins May put compression on abdomen to distend the pelvicalyceal system Release image to show ureters and bladder Post micturition image of bladder. • • • • • Control images essential Iodine containing water soluble contrast given I.V Filtered by the kidney into the collecting system. Standard sequence of images taken. Immediate-nephrogram phase- contrast in the glomeruli and proximal tubules. L. Adrenal Gland Stomach Spleen Pancreas Liver Splenic Flexure 2nd part of duodenum Descending Colon Hepatic Flexure Jejunum Relation of kidneys- Right • Anterior- Peritoneum, right lobe of liver, duodenum, colon, hepatic flexure • Posterior- diaphragm, quadratus lumborum • Lateral- abdominal wall • Medial- Psoas major muscle, IVC, gonadal veins, ureter. Relation of kidney Left • Anterior- Peritoneum, stomach, splenic flexure, tail of pancreas, small bowel, spleen • Posterior- diaphragm, quadratus lumborum • Medial- Aorta, gonadal veins, psoas major, ureter. • Veins lie anterior to the arteries and there may be multiple renal arteries. • Veins are bigger than arteries- veins are flat and irregular arteries are nice and round. • Right renal vein shorter than left renal vein. • Usually quite a bit of fat inbetween right kidney and adrenal so a lot higher up. • Left adrenal is usually more medial and slightly lower down. Ureter • Runs from renal pelvis to bladder and is approximately 25 cm long. • Lies on the medial edge of psoas in abdomen and enters pelvis by crossing common iliac vessels. • Ureter crosses in front of veins and arteries. • Runs along lateral pelvic wall and enters bladder posteriomedially at bladder base at edge of the trigone. 20 min release image CT Urogram Post micturition image • Consider radiation dose • Is there a need for a pre contrast scan to look for stones Ultrasound • No contrast or radiation, good for renal size, hydronephrosis, stones , some tumours, but relies heavily on whether the operator is good or not. Demonstrate the main components of the posterior abdominal wall from diaphragm to pelvic inlet. The Kidney Congenital Variants Urinary bladder • Midline structure covered superiorly by peritoneum. • Superior relations- Small bowel and sigmoid colon • Anteriorly- Pubic symphysis • Laterally- Levator ani and obturator internus • Circular muscle in the wall condenses to form internal urethral sphincter at bladder neck. Horseshoe kidney• The kidneys are close together in the embryonic pelvis. In approximately 1 in 600 fetuses, the inferior poles (rarely, the superior poles) of the kidneys fuse to form a horseshoe kidney • This U-shaped kidney usually lies at the level of L3–L5 vertebrae because the root of the inferior mesenteric artery prevented normal relocation of the kidneys. • Horseshoe kidney usually produces no symptoms; however, associated abnormalities of the kidney and renal pelvis may be present, obstructing the ureter Stuart's Anatomy of the Abdomen and Pelvis Page 17 • • • • • Midline structure covered superiorly by peritoneum. Superior relations- Small bowel and sigmoid colon Anteriorly- Pubic symphysis Laterally- Levator ani and obturator internus Circular muscle in the wall condenses to form internal urethral sphincter at bladder neck. fetuses, the inferior poles (rarely, the superior poles) of the kidneys fuse to form a horseshoe kidney • This U-shaped kidney usually lies at the level of L3–L5 vertebrae because the root of the inferior mesenteric artery prevented normal relocation of the kidneys. • Horseshoe kidney usually produces no symptoms; however, associated abnormalities of the kidney and renal pelvis may be present, obstructing the ureter • Horseshoe kidney results in a higher chance of hypertension and renal calculi. Female • Uterus and cervix lie posteriorly in the midline. Position of the uterus is very variable – anteverted, retroverted, affected by the degree of bladder filing • Ureters enter the bladder base around the cervix • Urethra - very short - anterior to the vagina • Ovaries - lie on the pelvic side wall on the iliac vessels but may “fall” into the pouch of Douglas or be displaced anteriorly and laterally . 1- Rectus Abdominis 2- Urinary Bladder 3- Vagina 4- Ureter/ Round ligament 5- Body of uterus 6- Cervix 7- Colon 8- Vertebrae Note sure if those labels are correct so you may want to check, but they seemed to fit and make sense. http://sprojects.mmi.mcgill.ca/gyn ecology/anatsagfrmd.htm Duplex collecting system • Embryologically, duplication occurs when two separate ureteric buds arise from a single Wolffian Duct. • Radiographical features may include duplicated ureters extending a variable distance down to the bladder and obstruction of the upper pole moiety down to the bladder, often with a ureterocoele. • Pain in the back may occur after drinking excessively. Male • Prostate lies inferiorly at the bladder base– surrounds the prostatic urethra • Seminal vesicles lie on either side of the bladder base- vas deferens 5 1- Urinary Bladder • Urethra 7 2- Prostrate gland 6 1 3- Urethra 4- Anus 5- Vertebrae 6- Colon 7- Rectus Abdominis 2 Note sure if those labels are correct so you may want to check, but they seemed to fit and make sense. 3 Others: • Additional disorders may include an extra renal artery and a pelviureteric junction obstruction. Renal colic- On a radiograph black fluid will be trapped behind a stone which will be relatively white. 4 Cystourethrography • Retrograde urethography - inject contrast via the urethral meatus • Antgrade urethrography - fill bladder with contrast (usually via a catheter as too dilute after an IVU). Fluoroscopy with spot images during voiding • Possible to measure bladder and rectal pressures during voiding to get an idea of function. Aorta Imaging Modalities • • • • Extends from diaphragmatic hiatus to bifurcation at level of 4th lumbar vertebra < 50 yrs - should be < 2 cm in diameter >50 yrs - considered aneurysmal if > 3 cm Divides into R and L common iliac arteries which divide into internal and external iliac arteries. • Also midline median sacral branch Abdominal Arteriography • • • • • Local anaesthetic in groin over the palpable femoral artery Puncture femoral artery ( usually Rt) Pass guide wire through needle up the femoral and iliac arteries into the aorta Remove needle leaving guide wire in place Pass catheter over guide wire into aorta • Aortogram - injection of contrast into aorta • Selective renal / coeliac / mesenteric arteriogram - manipulate catheter tip into origin of the appropriate vessel and then inject contrast • DSA (digital subtraction angiogram) - electronically subtract the background to display only contrast in the vessels. Coeliac Axis Major Paired Branches ○ Renal arteries May be more than one to each kidney Arise anterolaterally at approximately same level as SMA- lower border of L1 Right renal artery passes behind IVC (Left renal vein passes anterior to the aorta) Gonadal arteries Stuart's Anatomy of the Abdomen and Pelvis Page 18 Venous Phase ○ ○ ○ ○ (Left renal vein passes anterior to the aorta) Gonadal arteries Adrenal arteries Phrenic arteries Lumbar arteries Arterial Phase Superior Mesenteric Artery Anterior branches: • Coeliac Axis - stomach, liver, spleen, pancreas and duodenum • Superior mesenteric - small bowel and colon to splenic flexure • Inferior mesenteric to distal colon and rectum Demonstrate how to palpate the kidneys in a living subject. • The kidneys are often impalpable. In lean adults, the inferior pole of the right kidney is palpable by bimanual examination as a firm, smooth, somewhat rounded mass that descends during inspiration. Palpation of the right kidney is possible because it is 1–2 cm inferior to the left one. • To palpate the kidneys, press the flank (side of the trunk between the 11th and 12th ribs and the iliac crest) anteriorly with one hand while palpating deeply at the costal margin with the other. The left kidney is usually not palpable unless it is enlarged or a retroperitoneal mass has displaced it inferiorly. Stuart's Anatomy of the Abdomen and Pelvis Page 19 Arterial Phase Venous Phase Multiplanar CT scans showing an aortic aneurysm Visceral Pain 22 May 2012 08:54 Learning Objectives Describe the origins and pathways by which autonomic nerves reach the abdomen. Describe the origins and pathways by which autonomic nerves reach the abdomen. Discriminate between the distributions and motor functions of the sympathetic and parasympathetic nerves in the abdomen. Compare the sensory functions of the sympathetic and parasympathetic nerve supplies in the abdomen. Outline the segmental pattern of pain fibre distribution to the abdominal viscera. Explain the concept of referred pain and identify the most probable sites to which pains of abdominal visceral or diaphragmatic origin are likely to be referred. Sympathetic nervous system- arises from the T1-L2 spinal cord segments. Parasympathetic nervous system- arises from cranial nerves, III, VII, IX, X (oculomotor, facial, glossopharyngeal and vagus) and spinal cord segments S2-S4. Discriminate between the distributions and motor functions of the sympathetic and parasympathetic nerves in the abdomen. Afferent: • Sympathetic: pain • Parasympathetic: specific functional sensation e.g. stretch Efferent • Motor to smooth muscle • Secretomotor to glands Sympathetic from T1 – L2 Lt vagus n (Rt vagus not shown) Outline the segmental pattern of pain fibre distribution to the abdominal viscera. Rt sympathetic trunk (Lt trunk not shown) Explain the concept of referred pain and identify the most probable sites to which pains of abdominal visceral or diaphragmatic origin are likely to be referred. • The brain cannot localise pain sensation from structures for which there is no map in the cortex. These structures are the visceral organs and the diaphragm. • In these cases pain is referred to the regions of skin supplied by nerves with the same segmental supply (dermatomes) • In the abdomen, the nerve supply to the organ is autonomic. Dermatome • Area of skin supplied by a single spinal nerve (i.e. single segment of the spinal cord) • Adjacent dermatomes overlap so that on the trunk, at least three spinal nerves would have to be blocked to produce a region of complete anaesthesia. • No C1 dermatome. Note: No C1 dermatome. Anterior (left) & posterior (right) vagal trunks Diaphragm Splanchnic nerves Coeliac ganglion Splanchnic = visceral • Vagus travels along oesophagus in the abdominal region. • Ganglia are named according to the major blood vessels supplying the GI tract. Sympathetic chain Nerve pathways from the sympathetic chain to the abdomen Diaphragm Diaphragm Greater Greatersplanchnic splanchnic nerve nerveT5-9 T5-9 Lesser Lessersplanchnic splanchnic nerve nerveT10-11 T10-11 Nerves Nerves from from lumbar lumbar sympathetic sympathetic chain chain Least Leastsplanchnic splanchnic nerve nerveT12 T12 Splanchnic Splanchnic== visceral visceral Parasympathetic- Vagus nerve (CN X) and Sacral Outflow S2-S4 are the main supplies of the viscera. Referred Pain from Midgut Structures Peripheral vessels and skin- Nerves run with somatic nerves to same region (sympathetic only) Compare the sensory functions of the sympathetic and parasympathetic nerve supplies in the abdomen. Autonomic plexuses and ganglia Afferent pain fibres from midgut structures enter the spinal cord at T10 segment. Skin of umbilical region is also supplied by T10 spinal nerve Umbilical pain: pain from midgut structures (from duodenal papilla to splenic flexure) including inflamed appendix referred to periumbilical region. It is usually colicky (intermittent with bowel contractions) • The autonomic nerves to the abdomen are routed via plexuses surrounding the aorta and its branches. • Sympathetic nerves synapse at ganglia associated with these plexuses. • Plexuses and ganglia are named according to the associated blood vessels. • Plexus- Interconnecting network of nerves Plexus Anterior (left) Vagal trunk Ganglia & trunks Superior mesenteric ganglion Coeliac trunk & ganglion Renal plexus & ganglion Stuart's Anatomy of the Abdomen and Pelvis Page 20 Inferior mesenteric ganglion is also supplied by T10 spinal nerve Umbilical pain: pain from midgut structures (from duodenal papilla to splenic flexure) including inflamed appendix referred to periumbilical region. It is usually colicky (intermittent with bowel contractions) Plexus Anterior (left) Vagal trunk Ganglia & trunks Superior mesenteric ganglion Coeliac trunk & ganglion • When the inflammation of the appendix spreads to the surrounding peritoneum the pain becomes localised and constant at the right inguinal region. Movement of the hip joint and coughing elicits pain. Foregut structures • Epigastric pain- pain from foregut structures (as far as duodenal papilla) is referred to this region. Structures involved: Stomach, proximal duodenum, pancreas, liver, gall bladder. T7/T8 Hindgut structures • Suprapubic (hypogastric) pain: pain from hindgut structures descending colon to anal canal is referred here. T7-8 T10 Renal plexus & ganglion Inferior mesenteric ganglion Sympathetic trunk & ganglion Superior hypogastric plexus Inferior hypogastric plexus Parasympathetic nerves from vagus (X) To organs supplied by: Sympathetic nerves from sympathetic chain (T5-L2) Superior mesenteric artery T10-11 / X T11-L2 Coeliac artery T5-9 / X Renal arteries T10-12 / X Testicular/ovarian arteries T10-11 / X Foregut- Epigastric- T7/T8 Midgut- Umbilical- TX Hindgut- Suprapubic- T12/L1-L2 Inferior mesenteric artery T12-L2 / S2-4 Parasympathetic nerves from sacral outflow (S2-4) Stuart's Anatomy of the Abdomen and Pelvis Page 21 Superior and inferior hypogastric plexuses T12-L2 / S2-4 Non- Reproductive Peritoneum 22 May 2012 08:54 Learning Objectives Introduction Define the pelvic floor, identify its nerve supply and indicate its importance. Describe the course of the ureters from the renal pelvis to the entry into the urinary bladder The Pelvic Girdle Describe the relations of the ureters to the uterine arteries and the cervix Describe the shape, position and relations of the bladder in the male and female pelvis Left hip bone Right hip bone Explain the anatomical relations of the full urinary bladder Sacrum Describe the shape, relations and arterial supply of the rectum Pubic angle 2/29 • Sacro-ilial join is a synovial joint. • 2 foramen- Obturator foramen and Pelvic angle. Right Hip Bone Acet Fossa • All 3 bones meet in the acetabulum. • In a child they would not all be fused. Right Hip Bone & Sacrum Posterior Iliac fossa sacrum Pelvic wall: Sacrum & coccyx, pelvic bones coccyx Sacrospinous and sacrotuberous ligaments Medial view • Child during birth has to leave through pelvic inlet. • Siatic notches are the curved parts of pelvis that are divided by the sacrospinous ligament. Abdominopelvic Cavity Axis of abdominal cavity Describe the course of the ureters from the renal pelvis to the entry into the Pelvic inlet Stuart's Anatomy of the Abdomen and Pelvis Page 22 Axis of pelvic Abdominopelvic Cavity Axis of abdominal cavity Describe the course of the ureters from the renal pelvis to the entry into the urinary bladder • The ureters are muscular tubes that transport urine from the kidneys to the bladder. • They are continuous superiorly with the renal pelvis, which is a funnel -shaped structure in the renal sinus. • The renal pelvis is formed from a condensation of two or three major calices, which in turn are formed by the condensation of several minor calices. The minor calices surround a renal papilla. • The renal pelvis narrows as it passes inferiorly through the hilum of the kidney and becomes continuous with the ureter at the ureteropelvic junction. • Inferior to this junction, the ureters descend retroperitoneally on the medial aspect of the psoas major muscle. • At the pelvic brim, the ureters cross either the end of the common iliac or the beginning of the external iliac arteries, enter the pelvic cavity, and continue their journey to the bladder. Pelvic inlet Axis of pelvic cavity Perineum Pelvic outlet The pelvic cavity is coloured red. Note that its axis is angled about 450 back from the abdominal cavity (blue). Pelvic cavity • The iliac fossae form a shallow basin containing lower abdominal viscera. • The axis of the pelvic cavity is antero-inferiorly incline. • Pelvic cavity is conical or cylindrical (birth canal) • Cavity is mainly lined by muscles and nerves. Define the pelvic floor, identify its nerve supply and indicate its importance. Pelvic Wall Muscles and Ligaments Two muscles are attached to the medial surface of the greater trochanter of femur Constriction of the ureters can occur at: 1. Ureteropelvic junction 2. Where the ureters cross the common iliac vessels at the pelvic brim/ 3. Where the ureters enter the wall of the bladder. Sacrospinous ligament Sacrotuberous ligament Medial aspect of right pelvic wall • As a result kidney stones (renal calculi) can become lodged at these areas. Describe the relations of the ureters to the uterine arteries and the cervix • In the pelvis, the ureter is crossed by: 1. The ductus deferens in men 2. The uterine artery in women. • The pelvic floor is formed by the pelvic diaphragm and, in the anterior midline, the perineal membrane and the muscles in the deep perineal pouch. • The pelvic diaphragm is formed be the levator ani and the coccygeus muscles from both sides. • The pelvic floor separates the pelvic cavity, above, from the perineum, below. Pelvic diaphragm- This is the muscular part of the pelvic floor. • Shaped like a bowl or funnel and attached superiorly to the pelvic walls, it consists of the levator ani and coccygeus muscles. Describe the shape, position and relations of the bladder in the male and female pelvis Ureter Ductus deferens Urogenital diaphragm Prostate gland The Pelvic Wall Medial aspect of right pelvic wall Ligaments not shown Sagittal section Male Pelvis Levator ani Stuart's Anatomy of the Abdomen and Pelvis Page 23 Most of the pelvic bone facing the pelvic cavity is covered by the obturator internus muscle and its fascia Male Pelvis Levator ani Most of the pelvic bone facing the pelvic cavity is covered by the obturator internus muscle and its fascia • Lumbosacral plexus supplies the lower limbs. Pelvic Diaphragm/ Pelvic Floor Coronal section Coronal section of male pelvis showing how the urinary bladder and prostate sit in the ‘bowl’ formed by Levator ani. The fat-filled space labelled IF is the ischio-anal fossa • The muscle groups are collectively known as Levator ani which is very important in determining faecal continence. • The three muscles that make up levator ani are: a. Iliococcygeus b. Pubococcygeus c. Puborectalis • Obturator interus forms a tendonous arch. • Fat filled fossa allows anal canal to expand Internal urethral sphincter (smooth muscle) Anococcygeal ligament Tendinous arch (of obturator internus fascia) Obturator internus coccygeus External urethral sphincter (skeletal muscle) Medial aspect of right pelvic wall & floor Urethra = 20 cm The Pelvic Diaphragm Medial aspect of right pelvic wall & floor • Urethra can be damaged at 1st bend. • Easiest way to insert a catheter is by lifting the penis so it is straight which removes one of the bends Pudendal nerve Female Pelvis Ureter ovary The pelvic diaphragm consists of a bowl-like pair of skeletal muscles: Levator ani, which support the pelvic organs (bladder, cervix/uterus and rectum) Nerve supply: Pudendal (S2-4) & directly by S4 Pelvic Diaphragm Uterus Anterior Inferior view U.bladder Urethra = 4 cm Ischio pubic ramus Levator ani Anal canal Urethra Urethral opening Perineal Membrane Vaginal opening vagina (Only in female) Perineal body (fibromuscular mass) Urethral Sphincters- female Urethra •Two additional groups of muscles in females: 1. Sphincter urethrovaginalis Urethral orifice Vagina Stuart's Anatomy of the Abdomen and Pelvis Page 24 Anal opening •In females internal urethral sphincter is not well organized •External urethral sphincter is skeletal muscle surrounding the urethra in the deep perineal pouch External urethral sphincter Levator ani 2. Compressor urethrae This view of the pelvic diaphragm illustrates the openings in Levator ani for the urethra, vagina (in female) and anal canal. • Thick fascial sheet called perineal membrane- occupies anterior part. • Because of vagina in women the structure is weaker. • Keystone that has to be preserved during surgery- perineal body. Pelvic floor and perineum • A bowl like sheet of muscle called levator ani that forms the pelvic diaphragm. • Slung from the pelvis and sacrum. perineal pouch •Two additional groups of muscles in females: 1. Sphincter urethrovaginalis Urethral orifice Vagina Pelvic floor and perineum • A bowl like sheet of muscle called levator ani that forms the pelvic diaphragm. • Slung from the pelvis and sacrum. • Supports the main pelvic viscera (bladder, uterus, rectum) • Below the diaphragm is the Perineum, containing voluntary sphincters and external genitalia. 2. Compressor urethrae Explain the anatomical relations of the full urinary bladder Describe the shape, relations and arterial supply of the rectum The Rectum Levator ani ‘Rectum’ is Latin for ‘straight’, but the human rectum has a double-S bend, probably functioning as an anti-gravity device keeping load off the sphincter • Superior rectal artery is an offshoot of the Inferior Mesenteric Artery The Rectum and Anal Canal • The apex of the bladder is directed toward the top of the pubic symphysis; a structure known as the median umbilical ligament continues from it superiorly up the anterior abdominal wall to the umbilicus. The Urinary Bladder Anorectal junction Anal canal Anterior The rectum is supplied by the autonomic NS and is mainly sensitive to filling. The anal canal is supplied by somatic nerves and is extremely sensitive to injury. Anterior The Rectum and Anal Canal The tetrahedral bladder has a structure at each corner • The bladder is the most anterior of the pelvic viscera. Despite being part of the pelvic cavity when empty, it expands superiorly when full into the abdominal cavity. • Tetrahedral when empty • Ureters enter at supero-posterior angles • Urethra leaves through inferior angle • Superior surface covered in peritoneum • Expands between transversalis fascia and lining peritoneum • Smooth muscle sphincter (vesicae) at neck • Skeletal muscle sphincter (urethrae) in perineum Anterior The skeletal muscle sphincter ani surrounding the anal canal is much less important to faecal continence than the puborectalis part of Levator ani, which puts a sharp angle into the recto-anal junction. Can be injured in a badly-performed episiotomy Qu. 1: Which artery supplies pelvic organs (not ovaries and testis)? • Puborectalis- Forms a loop around the rectum which puts in a sharp junction which helps to ensure continence. External Iliac artery Inferior mesenteric artery Obturator artery X Internal Iliac artery None of the above X Mark = -6 (conf=3 ) Best Option: Obturator artery The best answer is obturator artery. The pelvic organs are supplied by named branches of the internal iliac, not by the internal iliac artery itself. The obturator and iliolumbar Stuart's Anatomy of the Abdomen and Pelvis Page 25 Rectum and Anal Canal • • • • • • Rectum descends within concavity of sacrum Shows three lateral curvatures Right-angle bend back at recto-anal junction Smooth muscle (internal) and skeletal muscle (external) sphincters Main functional sphincter is pubo-rectalis sling of levator ani Nerves: rectum - visceral; anal canal - somatic Describe the venous drainage of the rectum and anal canal and explain the None of the above X Mark = -6 (conf=3 ) Best Option: Obturator artery The best answer is obturator artery. The pelvic organs are supplied by named branches of the internal iliac, not by the internal iliac artery itself. The obturator and iliolumbar arteries are such branches (note that they do not supply viscera). • • • • Right-angle bend back at recto-anal junction Smooth muscle (internal) and skeletal muscle (external) sphincters Main functional sphincter is pubo-rectalis sling of levator ani Nerves: rectum - visceral; anal canal - somatic Describe the venous drainage of the rectum and anal canal and explain the occurrence of piles. Pasted from <https://www.ucl.ac.uk/lapt/laptlite/sys/run.htm?icl08_pelvis_abdom?f=clear?i=icl1?k=1?u=_st1511?i=Imperial > Arterial Supply of Pelvic Organs • The rectal venous plexus surrounds the rectum and communicates with the vesical venous plexus in the male, and the uterovaginal plexus in the female. • A free communication between the portal and systemic venous systems is established through the haemorrhoidal plexus. ant Internal iliac artery has anterior and posterior divisions The Internal Iliac Artery supplies all the pelvic organs (except the ovaries), the pelvic walls and much of the End buttock (gluteal) region 28/29 Venous Supply of Pelvic Organs • The Rectal venous plexus consists of two parts, an internal in the submucosa and an external outside the muscular coat. Internal plexus • The internal plexus presents a series of dilated pouches which are arranged in a circle around the tube, immediately above the anal orifice, and are connected by transverse branches. • This internal plexus is also known in some medical communities as the Irving plexus. External plexus • The lower part of the external plexus is drained by the inferior rectal veins into the internal pudendal vein • The middle part of the external plexus is drained by the middle rectal vein which joins the internal iliac vein. • The upper part of the external plexus is drained by the superior rectal vein which forms the commencement of the inferior mesenteric vein, a tributary of the portal vein. Haemorrhoids • The inferior part of the rectal plexus around the anal canal has two parts, an internal and an external. • The internal rectal plexus is in connective tissue between the internal anal sphincter and the epithelium lining the canal. • This plexus connects superiorly with longitudinally arranged branches of the superior rectal vein that lie one in each anal column. • When enlarged, these branches form internal hemorrhoids, which originate above the pectinate line and are covered by colonic mucosa. • The external rectal plexus circles the external anal sphincter and is subcutaneous. Enlargement of vessels in the external rectal plexus results in external hemorrhoids. Stuart's Anatomy of the Abdomen and Pelvis Page 26 Male Pelvis 29 May 2012 08:48 Identify the component bones of the pelvis and the following landmarks: iliac crest, anterior superior iliac spine, anterior inferior iliac spine, pubic symphysis, pubic tubercle, superior and inferior pubic rami, obturator foramen, ischial tuberosity, ischial spine. Distinguish structurally and functionally between the pelvis and the perineum. Explain the relationships of the urethra, urethral sphincter and erectile tissue masses in the female and the male perineum. Identify the component bones of the pelvis and the following landmarks: iliac crest, anterior superior iliac spine, anterior inferior iliac spine, pubic symphysis, pubic tubercle, superior and inferior pubic rami, obturator foramen, ischial tuberosity, ischial spine. Male & Female Pelves X = dist. between symphysis pubis to ant margin of acetabulum Y = diameter of acetabulum x Demonstrate the positions and explain the functions of the ductus deferens, seminal vesicles and the prostate gland. Explain the relationships of the urethra, urethral sphincter and erectile tissue masses in the female and the male perineum. Explain the anatomical considerations involved in passing a urinary catheter in a male. Preprostatic part • The preprostatic part of the urethra is about 1 cm long, extends from the base of the bladder to the prostate, and is associated with a circular cuff of smooth muscle fibres (the internal urethral sphincter). • Contraction of this sphincter prevents retrograde movement of semen into the bladder during ejaculation. Prostatic part • The prostatic part of the urethra is 3–4 cm long and is surrounded by the prostate. In this region, the lumen of the urethra is marked by a longitudinal midline fold of mucosa (the urethral crest). The depression on each side of the crest is the prostatic sinus; the ducts of the prostate empty into these two sinuses. • Midway along its length, the urethral crest is enlarged to form a somewhat circular elevation (the seminal colliculus). In men, the seminal colliculus is used to determine the position of the prostate gland during transurethral transection of the prostate. • A small blind-ended pouch—the prostatic utricle (thought to be the homologue of the uterus in women)—opens onto the centre of the seminal colliculus. • On each side of the prostatic utricle is the opening of the ejaculatory duct of the male reproductive system. Therefore the connection between the urinary and reproductive tracts in men occurs in the prostatic part of the urethra. Membranous part • The membranous part of the urethra is narrow and passes through the deep perineal pouch. During its transit through this pouch, the urethra, in both men and women, is surrounded by skeletal muscle of the external urethral sphincter. Spongy urethra • The spongy urethra is surrounded by erectile tissue (the corpus spongiosum) of the penis. It is enlarged to form a bulb at the base of the penis and again at the end of the penis to form the navicular fossa. The two bulbourethral glands in the deep perineal pouch are part of the male reproductive system and open into the bulb of the spongy urethra. The external urethral orifice is the sagittal slit at the end of the penis. • Narrowest part is the external urethral orifice- if a catheter can get through this it should go all the way to the bladder. • Weakest part of the urethra is the membranous part of the urethra. x y y Female Pelvis (singular) Male Pelvis Pelvic inlet Oval/round Narrow/heart shaped Sub pubic angle Wide > 80 degrees Narrow 50 -60 degrees Ischial spines Not projecting medially Project medially Greater (false) pelvis Shallow Deep Lesser (true) pelvis Wide, shallow & cylindrical Narrow, deep & tapering Y:X ratio (acetabulum) Less than one 1 or > 1 • Main function of female pelvis is for childbirth. Orientation of the Pelvic Girdle Male & Female Male Urethra • In men, the urethra is long, about 20 cm, and bends twice along its course. • Beginning at the base of the bladder and passing inferiorly through the prostate, it passes through the deep perineal pouch and perineal membrane and immediately enters the root of the penis. • As the urethra exits the deep perineal pouch, it bends forward to course anteriorly in the root of the penis. When the penis is flaccid, the urethra makes another bend, this time inferiorly, when passing from the root to the body of the penis. During erection, the bend between the root and body of the penis disappears. • The urethra in men is divided into preprostatic, prostatic, membranous, and spongy parts. Superior pubic ramus Male Female Explain the anatomical considerations involved in passing a urinary catheter in a male. Explain the contributions of the internal iliac and the gonadal arteries to the supply of the pelvic organs and walls. (plural) Self-study slide Learning Objectives In the anatomical position: ASIS and pubic tubercles are in the same plane ASIS Greater and lesser pelves are continuous Orientation of the axes of the abdominal & pelvic cavities (last lecture) Pelvic inlet Pubic tubercle • Parietal peritoneum continues into pelvic cavity but does not reach the pelvic floor. • Pelvic viscera (except ovaries and uterine tubes) are not completely covered by peritoneum. • Several folds and pouches are formed. • Space between pelvic wall and peritoneum not occupied by viscera contain pelvic fascia. • Pelvic fascial condensations form "ligaments" supporting viscera like cervix, vagina, prostrate. Demonstrate the positions and explain the functions of the ductus deferens, seminal vesicles and the prostate gland. Contents of male pelvic cavity • • • • Ureter, bladder, urethra Prostrate, ductus deferens, seminal vesicles, bulbourethral glands. Rectum Some of the abdominal GI tract spills into the greater pelvis- Caecum, appendix, parts of sigmoid colon and ileum. • Vessel, nerves and lymphatics. Ureter (25 cm) Parietal Peritoneum –cut edge Ampulla of ductus deferens Ductus deferens Ejaculatory duct Seminal vesicle not shown Distinguish structurally and functionally between the pelvis and the perineum. Urethra 20 cm long 1 2 Prostate gland Perineum Testis • The perineum is a diamond-shaped area between the pubic symphysis, ischial tuberosities and coccyx. Stuart's Anatomy of the Abdomen and Pelvis Page 27 Sagittal section Organs from several systems are packed in a small space. GI, urinary, reproductive, Nerves, vessels and lymphatics. Note the pelvis/perineum boundary. 1 & 2 indicates normal curvatures in male urethra Ejaculatory duct Seminal vesicle not shown Urethra 20 cm long Distinguish structurally and functionally between the pelvis and the perineum. 1 2 Prostate gland Perineum Testis • The perineum is a diamond-shaped area between the pubic symphysis, ischial tuberosities and coccyx. • Divided into anterior (urogenital) and posterior (anal) triangles. Pubic Symphysis Sagittal section Organs from several systems are packed in a small space. GI, urinary, reproductive, Nerves, vessels and lymphatics. Note the pelvis/perineum boundary. 1 & 2 indicates normal curvatures in male urethra • Prostate gland surrounds 1st (prostatic) parts of urethra • Ductus deferens from testis passes through inguinal canal, then over, and behind ureter to enter urethra through the prostate. • Seminal vesicles on back of bladder-open into ductus deferens between ampulla and ejaculatory duct. Ischial Tuberosity Male: Bladder and Prostate Coccyx Bony landmarks from the inferior aspect of the pelvis Prostate & urethra • Posterior compartment: there is the ischio-anal fossae- fat-filled spaces separating anal canal and levator ani from pelvic walls. • Anterior triangle divided into superficial and deep parts (or pouches) by the perineal membrane. Bulbourethral gland Corpus cavernosum Coronal section – anterior view Root of penis The male bladder ‘sits’ on the prostate, which is transfixed by the first (prostatic) part of the urethra. A urinary catheter, must negotiate a 900 bend in the urethra as it passes from the perineum to the pelvis. Prostate & Seminal Vesicle Ureter Bladder Ductus deferens and ampulla • Structure within the anal triangle are the same in both sexes. Seminal vesicle • Urine can collect in the superficial pouch if damage occurs from trauma. Superficial Perineal Structures of Male Ejaculatory duct Prostatic urethra Body of penis Crus of penis Glans of penis Posterior view Perineal membrane Ischiopubic ramus The ductus deferens, seminal vesicles & prostate empty into the prostatic urethra to form the semen • Ductus deferens run anterior to the ureter. • There are 2 seminal vesicles which secrete fluid. • Prostate gland has many ducts. Bulb of penis Levator ani (pelvic floor) muscles not shown Perineal membrane fills the urogenital triangle. The erectile tissues and associated skeletal muscles are anchored to this. • Ischial cavernosus is a muscle. • Bulbospongiousus is a muscle covering the body of the penis. Prostatic Urethra where urinary & reproductive tracts meet Internal urethral sphincter (smooth muscle) Internal urethral sphincter: Prostatic utricle (a cul-de-sac) Smooth muscle, well organized in males (not in females) Deep Perineal Structures of Male Closed during ejaculation by sympathetic stimulus. (Parasympathetic stimulation relaxes the sphincter) Openings of ejaculatory ducts (Skeletal muscle) Bulbourethral glands and ducts. Ducts open into the urethra below the perineal membrane External urethral sphincter (skeletal muscle) The tip of a urethral catheter can also become lodged in the prostatic utricle • • • • Stuart's Anatomy of the Abdomen and Pelvis Page 28 Posterior wall Small openings are for prostatic gland. Internal sphincter= smooth muscle External sphincter= skeletal muscle. During ejaculation the internal sphincter is closed- retrograde ejaculation. Ducts open into the urethra below the perineal membrane • • • • Small openings are for prostatic gland. Internal sphincter= smooth muscle External sphincter= skeletal muscle. During ejaculation the internal sphincter is closed- retrograde ejaculation. Male Urethra Basic arrangement • Deep transverse perineal muscle help keep pelvic diaphragm intact. 1.5 cm Anal triangle 2.5 cm • Superior rectal artery is a branch of IMA and joins with Inferior rectal artery to form a portal-systemic anastomoses. Rectum and Anal Canal 2 cm 15 cm External urethral orifice (narrowest part) Yellow arrows indicate areas of narrowing or obstruction for the navigation of a catheter. Explain the contributions of the internal iliac and the gonadal arteries to the supply of the pelvic organs and walls. Arterial Supply of Male Pelvis The rectum receives one pair of arteries from the inf. mesenteric artery and two pairs from the internal iliac artery. The venous drainage is similar, thus, there is an important portal-systemic venous anastomosis around the lower rectum and anal canal. • Perineal membrane is a thick triangular fascial structure attached to pubic arch. Posteriorly free margin. • Deep perineal space: is above the PM and below fascia of pelvic diaphragm • Superficial perineal space: is below PM and perineal fascia (subcutaneous tissue) • These spaces are potential spaces and they become real only when for e.g. fluid leaks into them. to prostate, bladder & ductus deferens Superficial Perineal Pouch- Male to bladder & ductus deferens to prostate Testis receives arterial supply from testicular artery arising form the abdominal aorta. (not from internal iliac artery) Pudendal nerve S2-4 Inferior rectal nerve Male superficial perineum. The pudendal nerve (S2-S4) provides all sensory and motor innervation. • • • • • Median erectile tissue mass (corpus spongiosum)- bulb of penis In females it divides round the vestibule to form vestibular bulbs Lateral erectile tissue masses (corpora cavernosae) attached to ischiopubic rami These meet to form shaft and head of penis or clitoris. Erectile tissue within perineum surrounded by skeletal muscles. • • • • • External iliac goes to the lower limb. Internal iliac supplies the pelvic organs Anterior division supplies organs Posterior division supplies gluteal muscles. Pudendal supplies perineum and external genitalia. • In a healthy man you can feel via a rectal examination the prostate gland. • Enlarged prostate- unable to pass urine easily due to compression of urethra. They also may need to urinate frequently due to enlarging and pressing on bladder which triggers urination. Penis Structure Corpus cavernosum x 1 v Superficial Perineal Pouch- Male Glans – part of corpus spongiosum Corpus spongiosum x1 v • MEAT IS MURDER!!!! grim Bulb of penis dissected to show erectile tissue columns and entry of urethra from the deep perineum Stuart's Anatomy of the Abdomen and Pelvis Page 29 Erectile Tissue in Male Corpus cavernosum The crura (legs) of the corpora cavernosae attach • MEAT IS MURDER!!!! grim Erectile Tissue in Male Bulb of penis dissected to show erectile tissue columns and entry of urethra from the deep perineum • Corpus cavernosum can be filled with blood- main artery is the pudendal artery supplying them. Corpus cavernosum Corpus spongiosum Male reproductive Tract root ureter Lateral view Right crus Membranous urethra Vas deferens root The urethra traverses the length of the corpus spongiosum. Catheters can get caught in the navicular fossa. Deep inguinal ring Ampulla of vas deferens Seminal vesicles Superficial inguinal ring Ejaculatory ducts Spermatic cord Prostate gland • PUDENDAL FTW!!! Bulbourethral glands Vas deferens Explain the contributions of the internal iliac and the gonadal arteries to the supply of the pelvic organs and walls. Perineal membrane Start here The crura (legs) of the corpora cavernosae attach to the ischiopubic rami. Testis in scrotum Urethra Glans Blood Supply of Penis • Ureter and vas deferens can cross over. Main blood supply: Testis and Associated Structures Longitudinal section Internal pudendal artery from internal iliac Deep artery – supplies corpora cavernosa Self-study slide Dorsal artery – supplies the skin and connective tissue 5 Artery of bulb – bulb, corpus spongiosum, glans and urethra. 4 Spermatozoa produced here 1 3 Branches supplying the cavernous spaces are usually coiled – helicine arteries 2 Parasympathetic stimulation causes helicine arteries to relax allowing blood flow 4 Spermatozoa stored here until ejaculation 31/43 • Tunica albuginea small space- hernia? What is the blood supply of the testis? • • • • Nerves of the pelvis Pelvic contents supplied by autonomic nerves only. Sympathetic from lower thoracic and upper lumbar (T10-L2) segments via hypogastric plexus Parasympathetic from S2-S4 Pelvic sensation is visceral and poorly localised- pain referred to suprapubic region and perineum. Nerves of Pelvis Erection, Emission and Ejaculation Neuro-vascular mechanisms Erection • Central parasympathetic pathway activated by psychic stimulation. Pudenal artery/arterioles relax and allow blood flow into cavernous spaces of erectile tissue (male and female) Secretion Pudendal nerve S2-S4 • Stimulation of para-sympathetic ganglie on prostate, seminal vesicle, and other glands (in females) Right & left inferior hypogastric plexus Emission • Central sympathetic pathway activated and smooth muscle contraction of vasdeferens, prostate, seminal vesicles. • Internal urethral sphincter (male) contracts. Bladder muscle contraction is prevented by sympathetic inhibitory action (no urine flow) Ejaculation • Entry of semen into urethra triggers somatic reflex (via pudendal nerve) causing contraction of bulbospongiosus muscle (skeletal) Detumescence • Selected sympathetic nerves supplying pudendal arterioles are activated causing arteriolar constriction to restrict blood supply to cavernous spaces. Pelvic sympathetic trunk Pelvic and perineal nerves: Pelvic sympathetic – T10 - L2 via hypogastric plexus; Pelvic parasympathetic – sacral outflow from S2-S4; Perineum (somatic): – Pudendal nerve S2-S4 • • • • Nerves of perineum Somatic nerves, mainly from sacral segments Most important nerve is pudendal (S2-4) Supplies all perineal skeleteal muscles Sensory to penis, lower urethra, lower rectum and anal canal. Lumbosacral Plexus Somatic nerves leave the pelvis from the lumbosacral plexus: Stuart's Anatomy of the Abdomen and Pelvis Page 30 The main supply to the perineum is Lumbosacral Plexus Somatic nerves leave the pelvis from the lumbosacral plexus: The main supply to the perineum is from the pudendal nerve S2-S4 ‘Pudendal’ derives from Latin pudere – to be ashamed Pudendal Nerve Important somatic nerve of perineum Pudendal nerve in the pudendal canal in fascia of obturator internus The pudendal nerve passes briefly from pelvis to buttock, thus passing behind the fibrous posterior edge of Levator ani (the sacrospinous ligament). Inferior rectal N (anal sphincter, levator ani m.) Levator ani Perineal N dorsal nerve of Penis (or clitoris) Motor brs to perineal muscles Post. Scrotal nerve (or labia) Stuart's Anatomy of the Abdomen and Pelvis Page 31 It passes forward below Levator ani, first in the lateral wall of the ischioanal fossa (posterior perineum) then branching to anterior perineum, penis/clitoris and scrotum/vulva. Female Pelvis 29 May 2012 10:03 Describe the arrangement of the cervical ligaments and explain their importance. Female Pelvic Organs Explain the structure, functions and clinical significance of the cervix and sketch its relationship to the vagina. Use simple sketches to explain the relationships of the labia majora, labia minora, vestibule, clitoris and urethral orifice. • • • • • • • Ovary, uterine (fallopian) tubes. Uterus and cervix Vagina Ureter, bladder, urethra Rectum Caecum, appendix, parts of sigmoid colon and ileum Vessels, nerves and lymphatics Describe what can be felt in a normal rectal examination in both sexes. Female Pelvic Organs: Overview Stability of the Cervix and Vagina Ureter Ovary (o) & uterine tube (UT) 3 sets of fibrous bands – the cervical ligaments – anchor the cervix in position within the pelvis. These prevent the uterus from prolapsing through the vagina. Uterosacral ligament Transverse cervical (cardinal) ligament Uterus & cervix (C) Urethra 4 cm long Sagittal section Cervix Pubocervical ligament • Cervix can herniate through vaginal wall after multiple childbirths. • Ligaments stabilise uterus. • Cardinal is most important. Uterus and Uterine tube • Consists of fundus, body, lower segment and cervix • Uterine tubes consist of infundibulum, ampulla, isthmus and uterine parts. • Potential communication between peritoneal cavity and exterior via the reproductive passageabdominal ostium of uterine tube and vaginal opening. (None exists in males) Vagina 10 cm long Internal anal sphincter Organs from several systems in the pelvic cavity. No sharing of reproductive and urinary passages in female. Female Peritoneum and Pelvic Fascia • Parietal peritoneum continues into pelvic cavity but does not reach the pelvic floor. • Uterine tubes are completely enveloped by peritoneum- the broad ligament. • Ovaries: suspended by mesovarium from posterior of broad ligament (not fully enveloped) • Pelvic fascial condensations form "ligaments" supporting viscera e.g. cervix, vagina, (prostate in males) • Important pouches in the female pelvis which can be palpated from the outside. • Ovaries are enveloped on one side or else eggs couldn't get released. Describe the arrangement of the cervical ligaments and explain their importance. Broad Ligament, Uterus, Uterine Tubes & Ovary Ovarian vessels Uterus, Uterine Tubes Ureter Peritoneal covering Suspensory ligament of ovary (Embryonic vestiges) Broad ligament Eye of sauron Round ligament Recto uterine pouch Uterus: Red circles & lines Vesico-uterine pouch Uterine Tube: Blue circles & lines •The broad ligaments are transverse mesenteries joining the uterus to the pelvic walls. • Their important contents are the uterine tubes and uterine arteries. • The ovary is suspended by the suspensory ligament of ovary. • Ovary is the weird acorn looking thing. • Recto uterine pouch- pouch of Douglas- some uterine vessels can be palpated. Posterior view • Fimbriae grab the egg and bring it into the uterus. • Ectopic pregnancy is very rare but means that the egg is fertilised in the uterine tube. Explain the structure, functions and clinical significance of the cervix and sketch its relationship to the vagina. • Fibro-muscular 'cylinder' with internal and external os. • Cervical canal lined by mucus secreting simple columnar epithelium. Vaginal surface (of cervix) Broad Ligament, Uterus, Uterine Tubes & Ovary (another view) Round ligament of uterus Remnant of gubernaculum to inguinal canal covered in stratified squamous epithelium (cervical smear test) • Projects into anterior vaginal wall at right angle to vaginal axis. • Held in position by strong cervical ligaments attached to pelvis and sacrum- part of pelvic fascia. Inferior pole of ovary Uterus – Cervix- Vagina Stuart's Anatomy of the Abdomen and Pelvis Page 32 The cervical canal enters the vagina through the upper part of its anterior wall, Ligament of ovary Rem of gubernaculum Posterior view Suspensory ligament of ovary. For vessels. Broad ligament of uterus peritoneum Inferior pole of ovary Uterus – Cervix- Vagina The cervical canal enters the vagina through the upper part of its anterior wall, the two tubes forming an angle of around 900 Ligament of ovary Rem of gubernaculum Suspensory ligament of ovary. For vessels. Broad ligament of uterus peritoneum Posterior view • • • • • Peritoneum covers anterior and posterior surface of uterus. External os of uterus opens into cervix Fimbriae are finger like projections guard the osteum of the uterine tube. One uterine tube opens into the peritoneal cavity. Ligament of ovary is part of the round ligament. Body is antiflexed on the cervix Cervix is anteverted on the vagina Anterior • Angle of anteversion of the uterus is between cervix and vagina • Angle of anteflexion is between uterine body and cervix. • Walls of pelvis supplied by sacral, gluteal and obturator branches. • Pudendal artery supplies perineum and recto-anal region (via inferior rectal branch) Cervix- Vagina Posterior fornix Anterior wall Of vagina Vaginal vault Vaginal canal Perineal membrane Female Pelvis: Internal Iliac Artery Anterior division of internal iliac a • Fibromuscular canal – 7 -9 cm • Vaginal fornices at upper end • Posterior fornix is important clinically • Urethra fused with the anterior wall • There are four fornices- the posterior and two lateral fornices are clinically important. • The bladder is very closely associated with the vaginal canal. • • • • • • Arterial Supply of Female Pelvis: Internal Iliac Artery • Main branches to pelvic viscera are a. Superior vesical b. Uterine c. Middle rectal Structures Palpable through the Vaginal Wall Cervix Ischial spine Sacral promontory Uterine artery pulse (lateral fornix) Ovary Some of these can be felt through rectal examination. Posterior division of internal iliac a Vaginal artery is equivalent to inferior vesical a in men The Uterine Artery • Main blood supply to uterus. Enlarges during pregnancy. • Runs medially towards cervix • Crosses urreter about 1cm from cervix. • Uterine branch runs close to uterus in broad ligament. • Ascending branch supplies uterine tubes and ovary. (Ovary has ovarian artery from abdominal aorta.) • Descending branch supplies vagina. • Uterine artery runs anterior to the ureter The Uterine Artery & Ovary Female Perineum The ovaries lie close to the openings of the uterine tubes into the peritoneal cavity. Inferior view Ascending branch Descending branch Uterine artery The ovary is on the posterior surface of broad ligament facing into the peritoneal cavity into which eggs are first released Ovaries and adjacent tubes receive an ovarian artery from the upper abdominal aorta. Ureters can be tied off accidentally with uterine arteries during hysterectomy – a classic disaster. Female perineum in lithotomy position Superficial Perineal Structures of Female Glans of clitoris from corpus spongiosum Body of clitoris from corpus cavernosum Covering the crus of clitoris Bulb of vestibule Female Urethra & Vagina Basic arrangement crus of clitoris Anterior 4 cm (= prostrate gland in male) Stuart's Anatomy of the Abdomen and Pelvis Page 33 Levator ani (pelvic floor) (Paraurethral gland in male ) Glans of clitoris from corpus spongiosum Body of clitoris from corpus cavernosum Covering the crus of clitoris Basic arrangement crus of clitoris Bulb of vestibule 4 cm Anterior (= prostrate gland in male) Levator ani (pelvic floor) muscles not shown (Paraurethral gland in male ) Perineal body 10 cm As in the male, the perineal membrane fills the urogenital triangle. The erectile tissues and associated skeletal muscles are anchored to this. • This is similar to a male in that you have a bulb covered by the bulbospongiosus muscle. Underneath ischiocavernosus muscle you have the crus of the clitoris. Deep Perineal Structures of Female • Females get more urinary infection because their urethra is shorter. Nerves of Pelvis • Pelvic contents supplied by autonomic nerves only. • Sympathetic from lower thoracic and upper lumbar segments via hypogastric plexus • Parasympathetic from S2-4 Outflow • Pelvic sensation is visceral and poorly localised, instead pain is referred to suprapubic regionand perineum. Nerves of Pelvis Anal triangle These structures are not present in the male Pudendal nerve S2-S4 Right & left inferior hypogastric plexus Perineal Spaces (or pouches) • Perineal membrane- Thick triangular fascial structure attached to pubic arch. Posteriorly there is a free margin and anteriorly there is a small gap. • Deep perineal space is above the PM and below the fascia of the pelvic diaphragm. • Superficial perineal space is below the PM and perineal fascia (subcutaneous tissue) • These spaces are potential spaces and they become real only when for example fluid leaks into them. Superficial Perineal Pouch- Contents • Median erectile tissue masses (corpus spongiosum). In females it divides round vestibule to form vestibular bulbs. The glans of clitoris is derived from this. • Lateral erectile tissue masses (corpora cavernosum). Paired cylinders, attached to ischiopubic rami. The body of clitoris is derived from these. • Erectile tissue within perineum surrounded by skeletal muscles. Use simple sketches to explain the relationships of the labia majora, labia minora, vestibule, clitoris and urethral orifice. Superficial Perineal Pouch & VulvaFemale Vestibule Vestibular bulbs The posterior part of the corpus spongiosum forms two large vestibular bulbs surrounding the lower vestibule and vagina. Perineal body Pelvic sympathetic trunk Pelvic and perineal nerves: Pelvic sympathetic – T10 - L2 via hypogastric plexus; Pelvic parasympathetic – sacral outflow from S2-S4; Perineum (somatic!) – Pudendal nerve S2-S4 Nerves of Perineum Anterior labial N (from ilioinguinal L1) Perineal br of post cutaneous N of thigh S1-S3 Pudendal N S2 – S4 Pudendal nerve S2-S4: main somatic nerve of the perineum. Motor to perineal muscles, anal & urethral sphincters, levator ani, Sensory to external genitalia (vestibule, labia minora and part of labia majora, lower vagina, clitoris, lower anal canal, Lymphatic drainage of Pelvis and Perineum • Pelvic organs drain mainly to external and internal iliac nodes (around the arteries) • Ovary and testis drain to para-aortic nodes. • Perineum (including anal canal) and external genitalia drain to superficial inguinal nodes (subcutaneous below inguinal ligament) Lymphatic drainage of Pelvis and Perineum Describe what can be felt in a normal rectal examination in both sexes. • A digital rectal examination (DRE) is a straightforward procedure performed by a clinician and should be undertaken by all physicians at some stage during their training. • The procedure is performed by placing the gloved and lubricated index finger into the rectum through the anus. The anal mucosa should be palpated for mass lesions knowing that a small percentage of colorectal tumors may be directly palpable. • In the female the posterior wall of the vagina and the cervix can be palpated. In the male the prostate should be palpated. The central sulcus and left and right lobes are easily felt and any extraneous nodules or masses will be easily detected. Stuart's Anatomy of the Abdomen and Pelvis Page 34 Pelvic lymph drainage and nodes follow the arteries rectum through the anus. The anal mucosa should be palpated for mass lesions knowing that a small percentage of colorectal tumors may be directly palpable. • In the female the posterior wall of the vagina and the cervix can be palpated. In the male the prostate should be palpated. The central sulcus and left and right lobes are easily felt and any extraneous nodules or masses will be easily detected. • In many instances the digital rectal examination may be followed by proctoscopy or colonoscopy. • An ultrasound probe may be placed into the rectum to assess the gynaecological structures in females and the prostate in the male before performing a prostatic biopsy. Pelvic lymph drainage and nodes follow the arteries Perineal lymph drainage is to superficial inguinal nodes Stuart's Anatomy of the Abdomen and Pelvis Page 35