10.abdomem 1

SDU. SDU. LIZHENHUALIZHENHUA

Abdominal wall

JinYong Xu

Anatomy Department of AnHui Medical University


Boundaries of the abdomen

Boundaries Superiorly － xiphoid process, l

ower border of costal arch, 11th and 12th ribs, vertebra T12

Inferiorly － superior border of pubic symphysis , pubic crest, pubic tubercle, fold of inguinal canal, anterior superior iliac spine, iliac crest, the lower border of L5


The abdominal cavity :

Proper abdominal cavity

Pelvic cavityThe terminal line

The abdominal wall :

Anterior abdominal wall

Posterior abdominal wallThe posterior axillary line


The abdominal regions ——Nine regions

R. hypochondriac region

Epigastric region

L. hypochondriac region

R. lateral regions

Umbilical region

L. lateral regions

R. inguinal region

L. inguinal regionPubic region


The abdominal regions ——Four quadrants

Left and right upper quadrants

Left and right lower quadrants


Landmarks and surface anatomy

Xiphoid process Costal arch Anterior superior iliac spine Iliac crest Superior border of pubic symphysis Pubic tubercle


Landmarks and surface anatomy

Linea alba Rectus abdominis Tendinous intersections Linea semilunaris Umbilicus: at the level of L3 ~ L4 Inguinal ligament


Landmarks of abdomen

Pubic symphysis Pubic tubercle Iliac crest Umbiicus Linea semilunaris Transpyloric plane


Projection of the organs on the abdominal wall


Incision of the abdominal skin From xiphoid process to the pubic

symphysis ,encircling the umbilicus

From the upper border of the pubic symphysis to the pubic tubercle

Make a transverse incision along the both anterior superior iliac spines

Attention ： To avoid hurting the deep structures, incision of the skin should be superficial.


Anterolateral abdominal wall Layers ( from superficial to deep)

Skin

Superficial fascia

Anterolateral muscles

Transverse fascia

Extraperitoneal fascia

Parietal peritoneum


Anterolateral abdominal wall

Superficial fascia － divisions below umbilicus

Fatty layer (Camper’s fascia) continuous with the superficial fascia over the rest of the body.

Membranous layer (Scarpa’s fascia) superficial to the aponeurosis of the oblique externus abdominis.It continues with superficial fascial of penis,dartos of scrotum and perineum(called Colles fascia).


Superficial vessels and cutaneous nerves Superficail Arteries

The branches of posterior intercostal arteries,subcostal arteries and lumber arteries.

The branches of superior and inferior epigastric arteries.

Superficial epigastric a.

Superficial iliac circumflex a.


Superficial veins

Thoracoepigastric V. Axillary vein

Superficial epigastric V. The great saphenous vein

Paraumbilical veins

the hepatic portal vein


Cutanous nerves

The anterior and lateral branches of the lower six intercostal/subcostal nerves

Iliohypogastric nerve


Superficial vessels and cutaneous nerves

Lymph drainge Superficial lymph vessels a

bove the level of the umbilicus grain upward into the axillary Ln.

The vessels below this level drain downward into the superficial inguinal Ln.


The deep structures


Muscles of abdomen

Anterolateral group Obliquus externus abdominis Obliquus internus abdominis Transversus abdominis Rectus abdominis


Muscles of abdomen

Posterior group Quadratus lumborum Pso

as major


Obliquus externus abdominis

Position: superficial layer of muscles

General direction of fibers: downward, forward and medially (from superolateral to the inferomedial)


Obliquus externus abdominis

Structures Inguinal ligament Superficial inguinal ring

－ triangular-shaped hiatus in aponeurosis of obliquus externus abdominis ,supralateral to pubic tubercle


Superficial inguinal ring


Obliquus internus abdominis

Position:Deep to obliquus externus abdominis

General direction of fibres: upwards, forwards and medially(fan out from its origins)


Transversus abdominis

Position:Deep to obliquus internus abdominis

General direction of fibers: run horizontally forward.


Structures of the obliquus internus abdominis and transversus abdominis

Inguinal falx the lower margins of two muscle

s,arch over the deep inguinal ring,and become aponeurotic ,fuse to form the conjoined tendon

Be attached to the medial part of pecten of pubis

Cremaster muscle Derived from the lower fibers of t

he obliquus internus abdominis and transversus abdominis

Around the spermatic cord and testis


Rectus abdominis

Position: beside the medial line of the anterior abdominal wall

Origin: pubic crest and symphysis Insertion: xiphoid and 5th-7th costal carti

lages Tendinous intersections : 3-4 The semilunate line


Functions of 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 expiration. Flex, lateral flex, and rotate vertebral column


Regional Structrues of Abdominal Wall


The sheath of rectus abdominis ：

Formed by the aponeurosis of the obliquus externus abdominis,obliquus internus abdominis and transversus abdominis,

Enclose the rectus abdominis


The arcuate line Absent in about 4-5cm below the

umbilicus, where aponeuroses of

all three muscles form anterior layer,

the lower free border named the arcuate

line

Below this line rectus abdominis

in contact with transverse fascia



Above the arcuate

Anterior layerFormed by fusion of aponeurosis of obliquus externus abdominis and anterior leaf of aponeurosis of obliquus internus abdominis

Posterior layer Formed by the fusion of posterior leaf of aponeurosis of obliquus internus abdominisAnd aponeurosis of transversus abdominis.



Below the arcuate

Anterior layerFormed by fusion of aponeurosis of obliquus externus abdominis , obliquus internus abdominis and transversus abdominis.

Posterior layerAbsent or formed by transverse fascia


The linea albaThe Linea alba － by the junction of medial borders of the sheath of rectus abdominis from xiphoid to pubic symphysis


Deep vessels of abdomenArteries Superior and inferior epigastric arteris Lower posterior intercostal a. Subcostal a. Four lumbar a. Deep circumflex iliac a.

Veins:accompany with the corresponding arteries.


Deep nerves of abdomen

Lower five intercostals nerves Subcostal nerve

Run between obliquus internus abdominis and tranversus abdominis.

Muscular branches: the muscles of anterolateral abdominal wall

Anterior and lateral cutanous branches: in a serial order.



Iliohypogastric n. Arises from lumbar plexus Passes forward in the interval betw

een obliquus internus and tranversus abdominis

Pieces obliquus internus abdominis 2.5 cm medial to anterior superior iliac spine

Pieces aponeurosis of obliquus externus abdominisabout 2.5 cm above superficial inguinal ring



Ilioinguinal n. Arises from lumbar plexus Runs parallel with iliohypogastric n.

at a lower level Enters inguinal canal and exits thro

ugh superficial inguinal ring Supplies the transversus abdominis,

obliquus internus, and obliquus externus abdominis. It also supplies the skin just above the symphysis pubis and the scrotum or labia major.



Genitofemoral n. Arises from lumbar plexus Emerges through superficial inguin

al ring and supplies the cremaster muscle


Inguinal region

Boundaries Inferior border: Inguinal liga

ment Medial border: Lateral mar

gin of rectus abdominis Superior border: A horizont

al line drawn from anterior superior iliac spine to lateral margin of rectus abdominis(the semilunate line)


Inguinal canal

Position: oblique passage, 4cm long, located 1.5cm above medial half of inguinal ligament


Descent of testes

Seven-week embryo showing the 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 :the testis descending into the scrotum


Two openings

Deep inguinal ring

－ an oval hiatus formed by the transverse fascia ,lies approximately 1.5cm above midpoint of inguinal ligament


Two openings

Superficial inguinal ring － triangular-shaped hiatus in aponeurosis of obliquus

externus abdominis ,supralateral to pubic tubercle


Boundaries of inguinal canal

Anterior wall Aponeurosis of obliquus exter

nus abdominis Obliquus internus abdominis

(lateral third of wall)


Boundaries of inguinal canal

Posterior wall Transverse fascia Inguinal falx (conjoined ten

don)medially Roof － arcuate borders of obliq

uus internus abdominis and transversus abdominis Floor － inguinal ligament


contents

In males Spermatic cord Ilioinguinal nerve

In females Round ligament of uteru

s Ilioinguinal nerve


Inguinal Triangle (of Hesselbach)

Boundaries Medially: Lateral border

of rectus abdominis Laterally: Inferior epigast

ric artery Inferiorly: Inguinal ligam

ent


Indirect inguinal hernia and direct inguinal hernia

Direct inguinal hernia

Indirect inguinal hernia


Anterior abdominal wall

Transverse fascia:

Covers the deep surface of the transversus abdominis.

Parietal peritoneum

The most inner layer of the anter

olateral abdominal wall Extraperitoneal fascia :

A layer of loose connective tissue between the above two


★You must identify follow structures ！

Obliquus externus abdominis Inguinal ligament Superficial inguinal ring Obliquus internus abdominis Transversus abdominis Inguinal falx Rectus abdominis Tendinous intersections

Sheath of rectus abdominis arcuate line inferior epigastric artery Posterior intercostal a. Intercostals nerve Iliohypogastric n. Ilioinguinal n. Spermatic cord

10.abdomem 1

Health & Medicine

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