Download The inguinal canal

HUMAN ANATOMY
The Abdomen
Lee
[email protected]
Overview
• Five weeks in learning (including presetation
and
practice)
• Preview and review
• Be sure to come on time, 1: 20pm Monday
• Dissecting is the best way in learning anatomy;
try to use your hands more; cooperation---team
work
• Paper works after classes (maybe twice)
• Quizs in class
• Mark your dissecting skills .
Textbook:
ESSENTIAL CLINICAL ANATOMY 4th Keith Moore.
References：
Grant’s Dissector 12th
Eberhard K. sauerland
(Text book)
Clinical Anatomy for Medical Students, 7th Edition, Richard
Snell, Lippincott
Atlas of Human Anatomy, 4th Edition, Frank Netter
(3rd Ed is also suitable)
Grant's Atlas of Anatomy, 11th Edition, Agur & Lee, Williams &
Wilkins
Taber's Cyclopedic Medical Dictionary (Recommended)
The abdomen Ⅰ
• Introduction
the abdominal wall
the abdominal cavity
visceral organs
Key points:
1. layers of the
anterolateral abdominal wall;
2.Inguinal Region &Inguinal canal
◆Clinical
significance
1. know the abdominal incisions,
2. Identify the direct and indirect inguinal
hernia
Digestive System Organization
• Gastrointestinal (Gl) tract (Alimentary canal)
– Tube within a tube
– Direct link/path between organs
– Structures
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Mouth
Oral Cavity
Pharynx
Esophagus
Stomach
Duedenum
Jejenum
IIleum
Cecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anus
5
The abdominal wall
1. Surface landmarks
Boundaries, Planes and regions
2. Anterolateral abdominal wall
1. Muscles
2. Blood vessels and lymphatic drainage
3. Nerves
3. Inguinal region and inguinal canal
1.1 Body landmarks
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Xiphoid process
Costal arch
Anterior superior iliac spine “ASIS”
Iliac crest ( tubercle 5cm from asis)
Superior border of pubic symphysis
Pubic tubercle
Boundaries of the abdomen
Boundary
• Superiorly－
xiphoid process①, lower border of
costal arch ② ③, 11th and 12th
ribs, vertebra T12
• Inferiorly－
superior border of pubic symphysis⒀,
pubic crest⑿, pubic tubercle⑾,
fold of inguinal canal,
anterior superior iliac spine ASIS⑦,
iliac crest ⑥, spinous process of L5
The abdominal regions
——Nine regions
R. hypochondriac
region
Epigastric region
L. hypochondriac region
R. lateral regions
L. lateral regions
R. inguinal region
Hypogastric(Pubic) region
Umbilical region
L. inguinal region
2 horizontal planes: subcostal and transtubercular planes
2 vertical planes--- line joins the midclavicular to midpoint of inguinal
canal
The abdominal regions
——Four quadrants
• Left and right upper
quadrants
• Left and right lower
quadrants
• The median plane and the
transverse umbilicus
plane
Landmarks of abdomen
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Pubic symphysis
Pubic tubercle
Iliac crest
Umbilicus
Linea semilunaris1---9--5--13
Transpyloric plane L1
First layer－liver, gallbladder, stomach
Second layer－duodenum, pancreas, spleen
Third layer－suprarenal gland, kidney, ureter, inferior
vena cava, abdominal aorta, nerves and lymphatics
Relations of abdominal viscera
First layer－liver, gallbladder, stomach
Second layer－duodenum, pancreas, spleen
Third layer－suprarenal gland, kidney, ureter, inferior
vena cava, abdominal aorta, nerves and lymphatics
Anterolateral abdominal wall
9. Layers ( from superficial to deep)
• Skin
• Superficial fascia (2layers below umbilicus)
• Deep fascia
• Anterolateral muscles(3 layers of paired m,)
• Transversalis fascia
• Extraperitoneal fascia
• Parietal peritoneum
Anterolateral abdominal wall
1st . Skin
2nd .Superficial fascia -----• Fatty layer (Camper’s fascia) continuous
with the superficial fascia over the rest of the
body.
• Membranous layer (Scarpa’s fascia)
below umbilicus
passes over the inguinal ligament to fuse the
deep fascia of the thigh (fascia lata).
In the perineum, it is attaches on each side
to the margins of the pubic arch and is know
as Colles’ fascia.
3rd . Investing fascia (deep fascia)
Superficial vessels and cutaneous nerves
• Arteries
– Superficial epigastric a.
– Superficial iliac circumflex a.
• Veins
– Thoracoepigastric v.
– Superficial epigastric v.
• Cutaneous nerves (multi_segmental )
– Anterior and lateral cutaneous
branches of T 7~11 nerves
– the subcostal nerves T12
– Iliohypogastric n. ←L1
– ilio-inguinal n. ← L1
Superficial vessels and cutaneous nerves
• Lymph drainge
– Superficial lymph vessels above the
level of the umbilicus grain upward
into the pectoral Lymph Nodes.
– The vessels below this level drain
downward into the superficial
inguinal LN.
Muscles of abdomen
Muscles of abdomen
Anterolateral group
4 bilateral paired muscles
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External oblique abdominis
internal oblique abdominis
Transverse abdominis
Rectus abdominis
Muscles of abdomen
Posterior group
• Quadratus lumborum
• Psoas major
• iliacus
The combined muscle (iliopsoas) is
inserted into the lesser trochanter
of the femur. iliopsoas is the main
flexor of the thigh and trunk
4th . external oblique abdominis
• General direction of fibers:
inferior and anterior ;run
downward and inward.
• The aponeurosis of the
external oblique muscle passes
anterior to the rectus abdominis
and forms the anterior layer of
the rectus sheath.
external oblique abdominis
Structures
• Inguinal ligament ----the inferior edge
of the aponeurosis of external oblique,
extends from the anterior superior iliac
spine to the pubic tubercle . Thickened
and curved.
• Lacunar ligament ---- A part of the
•
aponeourosis continues posterior pubic
tubercle toward the superior pubic
ramus is termed the lacunar ligament.
Pectineal ligament
Superficial inguinal ring
Superficial inguinal ring
－
triangular-shaped defect in aponeurosis of
external oblique abdominis above pubic
tubercle;
medial and lateral crus; intercural fibers
5th .internal oblique abdominis
• Deep to external oblique
abdominis
• General direction of fibres:
upwards, forwards and
medially
• The aponeurosis of the
internal oblique muscle
divides into anterior and
posterior layers,to form
anterior and posterior
layers of the rectus sheath.
6th .Transversus abdominis
• Deep to internal oblique
abdominis
• General direction of fibers:
run horizontally forward.
• The aponeurosis of this
muscle contributes to the
rectus sheath.
Transversus abdominis
• Inguinal falx(conjoint tendon)
– internal oblique abdominis
has a lower, free border that arches
over spermatic cord
– Inserted with transversus
abdominis fiber into medial part
of pecten of pubis
• Cremaster
– Dirived from the lower fibers of
the internal oblique abdominis
and transversus abdominis
– Around the spermatic cord and
testis,
Rectus abdominis
• Position: lie on to either of midline
• Origin: pubic crest and symphysis
• Insertion: xiphoid and 5th-7th
costal cartilages
• Tendinous intersections 3-4
• linea semiluaris
• Linea alba
Similar functions for
above four pairs of muscles
• Support and compress the abdominal
viscera
• Increase intra-abdominal pressure, aid in
expulsive efforts-vomiting, coughing,
sneezing, defecation, urination and
childbirth.
• Depress ribs, assist in (the act of force
expiration.
• Flex, lateral flex, and rotate vertebral
column
Sheath of rectus abdominis
Anterior layer
• Formed by fusion of aponeurosis of
external oblique ;
anterior leaf of aponeurosis of
internal oblique
Posterior layer
•
posterior leaf of internal oblique and
transversus aponeurosis
• arcuate line ---- the aponeuroses of all
three muscles pass anterior to the rectus
muscles to reach the linea alba ,about 45cm below the umbilicus ; the lower free
border is arcuate line.
• Below this line rectus abdominis in contact
with transverse fascia
Sheath of rectus abdominis
anterior abdominal wall
1。skin
2。Camper fascia
3。Scarpa fascia
4. Anterior layer of
rectus sheath
5.Rectus abdominis
6. Posterior layer of
rectus sheath
7.Transversalis fascia
8. Extraperitoneal fascia
9. Parietal peritoneum
Muscles of abdomen
Linea alba
－The linea alba is a midline raphe,forming by the aponeuroses of the
abdominal muscles, extending vertically from the xiphoid process to the
pubic symphysis. a median incision through the linea alba is a common
surgical approach in acute abdomen.
.
Deep vessels of abdomen
Arteries
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Superior and inferior epigastric arteris
Inferior branch of posterior intercostal a.
Subcostal a.
Deep iliac circumflex a.
Four lumbar a.
Nerves
Subcostal nerve
Iliohypogastric nerve
Ilioinguinal nerve
Deep nerves of abdomen
• Lower five intercostals
nerves
• Subcostal nerve
• Iliohypogastric n.
• Ilioinguinal n.
Run between internal
oblique and tranversus
abdominis.
Lateral femoral cutaneous n.
Deep nerves of abdomen
Iliohypogastric n.
• Arises from lumbar plexusL1
• Passes forward between internal
oblique and tranversus abdominis
• Pierces internal oblique 2.5 cm medial
to ASIS
• Pierces aponeurosis of external
oblique about 2.5 cm above
superficial inguinal ring
Deep nerves of abdomen
Ilioinguinal n.
• Arises from lumbar plexusL1
• Runs parallel and inferior to the
iliohypogastric n.
• Enters inguinal canal and exits through
superficial inguinal ring
• Supplies the three flat muscles. It also
supplies the skin just above the pubis
symphysis and the scrotum ( greater lip
of pudendum).
※7th . Transversalis fascia-- deep inguinal ring
iliopubic tract
※8th .Extraperitoneal
fascia
• The peritoneum
is a continuous, transparent
serous membrane lining the
abdominopelvic wall , and
covers the organs .
• Parietal peritoneum
Sensitive,supplied by somatic N,
Pain from it is well localized .
• Visceral peritoneum
Insensitive,supplied by visceral N,
Pain is poorly localized
Foregut----epigastric region
Midgut---umbilical
Hindgut---pubic
Parietal peritoneum
5 folds
1.Median umbilical fold—remnant of urachus
2.Medial umbilical folds---umbilical artery
3.Lateral umbilical folds---inferior epigastric
vessles
※ 3 paired peritoneal fossae
1.Supravesicle fossae
2.Median inguinal fossea
=Inguinal Triangle (of Hesselbach)
3.Lateral inguinal fossae
Anterolateral abdominal wall
Layers ( from superficial to deep)
 1.Skin
 2. 3。Superficial fascia
 4. 5. 6. Anterolateral muscles
 7.Transversalis fascia
 8.Extraperitoneal fascia
 9.Parietal peritoneum
Inguinal region
Boundaries
• The area extends between ASIS
to pubic tubercle
• Exit and enter structures
• weakness ?
inguinal ligament
inguinal canal
inguinal triangle
Inguinal canal
Position: oblique passage, 4cm long, begins at the deep inguinal ring and
terminates at the superficial inguinal ring .located 1.5cm above medial half
of inguinal ligament .Transmits the spermatic cord or the round ligament
of the uterus and the ilioinguinal nerve .an indirect hernia(if presents)
passes the canal .
Boundaries of inguinal canal
• Anterior wall
– Aponeurosis of external
oblique abdominis and internal
oblique abdominis
• Posterior wall
– Transversalis fascia
– Aponeurosis of transverse
abdominis
• Roof－arching fibers of internal
oblique and transverse abdominis
• Floor－inguinal ligament
Boundaries of inguinal canal
Two openings
• Superfacial inguinal ring －a triangular-shaped defect in the
aponeurosis of the external oblique a, just lateral to the pubic
tubercle
• Deep inguinal ring－lies in transversalis fascia ,just lateral to the
inferior epigastric vessels .

openings：

Superficial inguinal ring
Deep inguinal
ring
Mechanics of the inguinal canal
• The inguinal canal is a site of potential weakness in both sexes.
• On coughing and straining (as in micturition, defecation, and parturition),
the arching lowers fibers of the internal oblique and transversus
abdominis contract and flatten the arch.
• In turn, this lowers the roof of the canal toward the floor and virtually
closes the canal.
Structures passing through
the inguinal canal
• In males
– Spermatic cord
– Ilioinguinal nerve
• In females
– Round ligament of uterus
– ilioinguinal nerve
Spermatic cord
Spermatic cord----cord-like structure in males formed
by the ductus deferens and surrounding tissues, run
from the abdomen to testis.
contents of spermatic cord :
3 arteries: artery to ductus deferens, testicular artery,
cremasteric artery;
3 fascial layers: external spermatic, cremasteric, and
internal spermatic fascia;
3 other structures: pampiniform venous plexus, ductus
deferens, testicular lymphatics;
3 nerves: genital branch of the genitofemoral nerve ,
autonomic and visceral afferent fibres, ilioinguinal nerve.
Testis: male gonad
Epididymis:
Scrotum:
Descent of testes
Seven-week embryo showing the
primordial testis before its descent from the
dorsal abdominal wall
Descent of testes
Fetus at 28 week the testis passing
through the inguinal canal
Descent of testes
Newborn
Congenital cryptorchidism (Undescended testis)
Inguinal Triangle (of Hesselbach)
Boundaries
• Medially: Lateral border of rectus
abdominis
• Laterally: Inferior epigastric artery
• Inferiorly: Inguinal ligament
Inguinal canal
The inguinal canal is an oblique passage through the abdominal wall.
About 3 to 5 cm long.
Occupied by the spermatic cord or by the round ligament of the uterus, also contains the
ilioinguinal nerve.
2 RINGS
The superficial inguinal ring is a triangular opening in the aponeurosis of the external
oblique muscle.
The deep inguinal ring is a slit-like opening in the transversalis fascia
4 WALLS
Anterior : the aponeurosis of the external oblique muscle , laterally, by internal oblique .
Posterior: formed by the transversalis fascia ; the aponeurosis of the internal oblique
transversus abdominis muscle, come together to the pubic attachments into conjoint
tendon (inguinal falx).
Superior: lateral--- transversalis fascia ;central---the arching fibers of the internal oblique
muscle and the transversus abdominis muscle, media---the medial crus.
Floor :the inguinal and lacunar ligaments.
The canal is potentially a weak area through which an inguinal hernia may occur.
Indirect inguinal hernia and
direct inguinal hernia
Direct inguinal hernia
Indirect inguinal hernia
Inguinal hernia is a protrusion of peritoneum(or~) through a weakness in the abdominal
wall in the region of the inguinal canal.
A direct inguinal hernia results from a weakness of the posterior wall of the inguinal canal and
herniation occurs medial to the inferior epigastric vessels .
An indirect inguinal hernia arises lateral to the inferior epigastric vessels, the protrusion
following the path of the spermatic cord or round ligament through the deep inguinal ring into
the inguinal canal. With an indirect inguinal hernia bowel can easily pass down the inguinal
Femoral hernia is a protrusion of a loop of the intestine through the femoral canal
located in the lower groin near the thigh, with the hernial neck lying below and lateral to
the pubic tubercle. Common in women --- over weight , have had several children.
Strangulation(constriction) of a hernia is an acute surgical emergency
The pectineal and lacunar ligaments are often used as anchor points for sutures.
Inguinal hernia repair
Anterior abdominal wall
• Transverse fascia
• Extraperitoneal fascia
• Parietal peritoneum
median incision
question?
How many
layers are there
in each part of
abdominal wall?
McBurney incisions
Layer ?
Subcostal incision
Muscle-splitting incision
Median or midline incision
Left paramedian incision
Transverse incision
Suprapubic incision
Landmarks and surface anatomy
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Linea alba
Rectus abdominis
Tendinous intersections
Linea semilunaris
Umbilicus: at the level of L3 ~ L4
Inguinal ligament
question
1. What
is the inguinal ligament?
The inguinal ligament is the thichened lower edge of the external oblique aponeurosis. It
extends from the anterior superior iliac spine to the pubic tubercle.
Medially, a small part is reflected backward to the pubis as ---the lacunar ligament, and its
lateral edge limits a gap (lacuna), which forms the medial boundary of a femoral hernia.
A further lateral extension along the pubis and behind the femoral vessels is known as the
pectineal ligament .
2.What are the boundaries of the inguinal triangle?
The inguinal triangle is bounded by the inferior epigastric artery, the lateral border of the
rectus, and the inguinal ligament. A direct inguinal hernia enters the inguinal canal through
the inguinal triangle.
New terms
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Inguinal ligament
Superficial (deep)inguinal ring
Transversus abdominis
Inguinal canal
Rectus abdominis
Tendinous intersections
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rectus sheath
arcuate line
inferior epigastric artery
Intercostals nerve
Iliohypogastric n.
Ilioinguinal n.
Spermatic cord
Hernia (herniation)
The struggle you’re
in today is
developing the
strength you need
for tomorrow.
Don’t give up.