Download Lab 9 – Abdomen

Lab 9 – Abdomen
MUSCLES
External abdominal oblique – continuous with the external intercostal muscle; its
fibers point in a caudal direction as it moves anteriorly until it inserts on the linea alba via
its aponeurosis; most superficial of the muscles of the abdominal wall; immediately
superficial to the internal abdominal oblique.
Aponeurosis – shaped a little like a bell; milky in appearance and flares
laterally as it approaches the inferior portion of the abdomen; it is a broad, flat
tendon.
Internal abdominal oblique – continuous with the internal intercostal muscle; its
fibers point in a cranial direction as it moves anteriorly until it inserts on the linea alba
via its aponeurosis; deep to the external abdominal oblique; superficial to the transverse
abdominis muscle; Dr. J has been known to tag this muscle! What an awful guy!
Aponeurosis – shaped a little like a "V" getting wider at the cranial end and
more narrow at the caudal end; milky in appearance; it is a broad, flat tendon.
Linea alba – white line where the aponeuroses of the anterior abdominal muscles fuse
with each other to form a single tendinous band; runs along the anterior midline from the
xiphoid process to the pubic symphysis; contains the umbilicus.
Psoas major – merges with the iliacus to form the iliopsoas which is the prime flexor
of the thigh.
Psoas minor – lateral to the Psoas Major; smaller of the 2 muscles
Quadratus lumborum – can be seen in two places in the cat: 1. in the thoracic
cavity running along the vertebral border just cranial to the diaphragm and 2. dorsal to the
psoas major in the abdomen.
Rectus abdominis – eight pack muscle of humans; it is enclosed within the
aponeurosis of the internal abdominal oblique; looks like bacon.
Transverse abdominis – deepest of the three muscles making up the majority of the
abdominal wall; immediately deep to the internal abdominal oblique; in the cat its fibers
move caudally as they approach the midline, while in humans it is more transverse.
Aponeurosis – shaped a little like a narrow oval.
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NERVES
Femoral nerve – emerges from the Psoas Major just before it passes deep to the
inguinal ligament; enters the thigh lateral to the femoral artery; gives rise to the
saphenous nerve.
Genitofemoral nerve – found adjacent to the external iliac artery.
Lateral cutaneous nerve – diameter of dental floss; found near the deep iliac
circumflex artery and runs obliquely in a caudal direction as it moves laterally, passes
through the internal and external abdominal oblique muscles.
Lumbar nerve – Medial and lateral lumbar nerves; found dorsal to the kidney and
lateral to the psoas major muscle. Usually close to the adrenolumbar artery or one of
its branches.
ORGANS
Cecum – very beginning of the colon. Looks like the Pope’s slippers.
Colon – looks like a huge question mark.
Common bile duct – begins at the union of the cystic duct and the hepatic duct. It
carries bile to the duodenum.
Cystic duct – cystic duct is on the cat's right and the hepatic duct is on the cat's left
side. These two ducts (quack) meet to form the common bile duct.
Diaphragm – anatomical barrier between the thoracic and abdominal cavities; dome
shaped; insertion is at the central tendon; phrenic nerve serves the diaphragm
Central tendon – insertion of the diaphragm; it is an aponeurosis and
connects the central portions of the diaphragm; phrenic nerve passes through the
central tendon on both sides as well as the caudal vena cava on the right.
Crura – musculotendinous extensions of the diaphragm; one on each side.
The singular for is crus.
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Esophagus – begins at the inferior end of the pharynx, passes through the diaphragm
and then enters the stomach.
Gall bladder – looks like a green raisin in the cat; found between the quadrate and
right medial lobes of the liver.
Hepatic duct – the hepatic duct comes from the liver on the cat’s left side and joins
the cystic duct (on the right) to form the common bile duct.
Kidney – kidney shaped organ; major excretory organ of the abdomen; has portal
circulation; right kidney is cranial to the left kidney in the cat. In humans the left is
superior to the right kidney.
Calyx – funnel or cup shaped space near middle of kidney.
Cortex – outer layer of the kidney; where the glomerulus, Bowman's capsule,
and part of the tubular system of the nephron are found; usually a lighter color
than the medulla.
Medulla – inner portion of the kidney; cat has a single piece medulla which is
called a pyramid; medulla is usually darker than the cortex. This is where the
loop of Henle is and where the collecting tubules drop the urine into the calyx.
Pyramid of medulla – cat has a single piece medulla which is called a
pyramid; usually darker than the cortex. Humans have 8 to 10 pyramids in each
kidney and pigs have 10 or more per kidney.
Liver – from left to right:
Left lateral lobe – caudal to the left medial lobe; it is the larger of the two
lobes on the left side.
Left medial lobe – cranial and medial to the left lateral lobe; it is the smaller
of the two lobes on the left side.
Quadrate lobe – found on the right side; it is between the gall bladder and the
left medial lobe; it is often four sided in appearance.
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Right medial lobe – cranial to the right lateral lobe and lateral to the quadrate
lobe; larger than the right lateral lobe.
Right lateral lobe – caudal to the right medial lobe and cranial to the caudate
lobe; smaller than the right medial lobe.
Caudate lobe – found on the right side; largest portion is caudal to the right
lateral lobe of the liver; caudate lobe can be seen in two places, one being the
papillary process of the caudate lobe. The papillary process is to the left of the
common bile duct and is covered on its ventral surface by the lesser omentum
(gastrohepatic ligament).
Papillary process of caudate lobe – only found on the right side;
relatively small portion of the caudate lobe and it is found dorsal to the
lesser omentum and to the left of the common bile duct and the hepatic
artery; it is one of the two portions of the caudate lobe of the liver that
can be tagged.
Pancreas – right lobe runs in a cranial/caudal direction adjacent to the duodenum and
the left lobe runs transversely from the cranial end of the duodenum to the spleen; looks
like hamburger helper.
Peritoneum – forms two abdominal organs, the greater omentum and the lesser
omentum; covers the abdominal wall as well as the organs; shiny material inside
transverse abdominal flap.
Greater omentum – part of the peritoneum; attached to the greater curvature
of the stomach and part of the duodenum; looks like mozzarella cheese in a hair
net; flip it up to see intestines.
Lesser omentum – part of the peritoneum; primarily between the stomach,
duodenum, liver and the diaphragm; much smaller than the greater omentum.
Rectum – portion of the large intestine that is between the sigmoid colon and the anal
canal.
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Small intestine:
Duodendum – first portion of the small intestine; the chyme enters the
duodenum from the stomach and material leaves the duodenum to enter the
jejunum; it is directed caudally from the pylorus of the stomach; travels adjacent
to the pancreas. In a humans this reflects and is directed transversely to the left.
Jejunum – makes up most of the small intestine in the cat and is highly coiled;
middle portion of the small intestine; receives material from the duodenum and
the material that leaves enters the ileum.
Ilem – less coiled than the jejunum; joins the large intestine at the ileocecal
junction; last portion of the small intestine.
Mesentery – also known as the mesenteric ligament; it is a double layer of
peritoneum that comes out around the small intestine; arteries, veins, nerves,
and lymphatics that come to and from the small intestine pass between these two
layers; prevents the small intestine from tying itself in knots.
Spleen – produces red blood cells before birth; important part of the lymphatic system;
can produce some white blood cells; it is the primary organ that removes old red blood
cells, old platelets and debris from the blood.
Stomach – stomach shaped organ between the esophagus and the duodenum of the
small intestine; has rugae in its walls.
Rugae – longitudinal folds in the walls in the stomach.
Suprarenal (adrenal) gland – endocrine glands; they are about 1 cm cranial and
medial to the kidneys.
Ureter – transports urine from the kidney to the urinary bladder; there are two
ureters, one on each side; can trace from kidneys.
Urethra – transports urine from the urinary bladder to the outside; trace from urinary
bladder.
Urinary bladder – receives urine from the two ureters and stores it until it is
discharged to the outside by means of the urethra; has rugae that allow it to expand
without increasing pressure..
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