Abdomen Anatomy

Surgical anatomy of

Anterior abdominal wall

by Wichien Sirithanaphol

Anterior abdominal wall

• Anterolateral part– External oblique muscle– Internal oblique muscle– Transverse abdominis muscle

• Middle part (or midline)– Rectus abdominis muscle– Pyramidal muscle– Rectus sheath

External Oblique Muscle

• Origin : inferior border of lower 8th rib

• Insertion : linea alba , iliac crest , ASIS

• Fibers pass inferiorly and medially" Hands in the front pockets "

• The external oblique fascia – Innominate Fascia of Gallaudet– Inguinal ligament– spermatic cord : external spermatic fascia

External oblique m.

Aponeurosis of external oblique

Internal Oblique Muscle

• Origin : thoracolumbar fascia and the iliac crest

• Insertion : Lower border of ribs 9-12 , linea alba

• Fiber pass upward and medially " Hands in the back pockets "

• The lowest fibers arch– spermatic cord or round ligament : cremasteric layer

Internal oblique m.

Cremaster m.

Transversus Abdominis Muscle

• Origin : Iliac crest , thoracolumbar fascia , lower ribs

• Insertion : linea alba , pecten pubis

• The deepest of the three flat anterior abdominal muscles

• Fibers pass medially

• Transversalis fascia

• Extraperitoneal fat

Transversus

Abdominis m.

Transversalis fascia

Transversus abdominis aponeurosis

Inferior fiber of

internal oblique

Pyramidalis m.

Rectus abdominis m.

Transversalis

fascia

Lateral border of rectus

Rectus Abdominis muscle• Origin : pubis and pubic symphysis

• Insertion : Cartilages of ribs 5-7th , xiphoid process

• 3 tendinous lines – the xiphoid process – the umbilicus– halfway between these points

Pyramidalis muscle

• inserts into the linea alba 3-4 cm above pubic creast• its insertion into the linea alba : landmark for an accurate midline incision

Linea semicircularis

Tendinous line

Rectus sheath

• Anterior rectus sheath

• Posterior rectus sheath

• The semicircular line of Douglas (linea semilunalis)

A above arcuate line

B below arcuate line

Umbilical Area

• A midline fusion of the medial borders of both rectus abdominis aponeurosis around the umbilical cord

• This fusion may take place around the 10th week

• Structures associated with the Umbilical Cord and Umbilicus

– umbilical vein → round ligament of the liver

– 2 umbilical arteries → medial umbilical ligaments

– Urachus → median umbilical ligament

Umbilical a & v.

Falciform lig

Umbilical v.

Umbilical a.

Round ligament

(obliterated umbilical v.)

Medial umbilical ligament

(obliterated umbilical a.)

Median umbilical ligament

(obliterated urachus)

Artery of the Anterior Abdominal Wall

• Superior epigastric artery (internal thorasic artery)• Inferior epigastric artery (ext.illiac artery)• Deep circumflex illiac artery (ext.illiac artery)• 3 branches of Femoral artery

– superficial circumflex iliac artery– superficial epigastric artery– superficial external pudendal artery

Superior epigastric a.

Deep circumflex iliac a.

Inferior epigastric a.

Superficial inferior epigastric a.

Superficial circumflex iliac a.

External oblique

perforators

Superficial inferior

epigastric a.

Superficial

circumflexiliac a.

superficial external pudendal artery

Lymphatic of anterior abdominal wall

Nerve Supply to

the Anterior Abdominal Wall

• Intercostal n.

• Subcostal n.• Iliohypogastric n.

• Ilioinguinal n.

A: Seventh to twelfth thoracic n.

B: First lumbar n.

Surgical anatomy of

Posterior abdominal wall

Posterior abdominal wall

• Lumbar vertebrae

• Paravertebral gutters– Psoas major – Quadratus lumborum– Iliacus– Erectoe spinae

• Fascia of posterior abdominal wall– Thoracolumbar fascia (lumbodorsal fascia)

Thoracolumbar fascia

Thoracolumbar fascia

• 3 layers of connective tissue– Anterior lamella– Middle lamella– Posterior lamella

Muscle Origin Insertion

External oblique • Inf border of lower 8 ribs • linea alba• iliac crest

• ASIS

Internal oblique • Iliac fascia

• Anterior iliac crest

• Lumbar aponeurosis

• Lower border of ribs 9-12

• linea alba

• Pecten pubis

Transversus abdominis

• Iliac crest

• Lumbodorsal fascia

• Cartilages of lower ribs

• linea alba

• Pecten pubis

Rectus abdominis • pubis and pubic symphysis • Cartilages of ribs 5-7

• Xiphoid process

Pyramidal • Pubis

• Anterior pubic ligament

• Linea alba

Muscle Origin Insertion

Quadratus lumborum • Iliolumbar ligament

• Posterior iliac crest

• 12th rib

• Transverse processes L1-4

Internal oblique • Transverse processes L1-5

• Bodies/fibrocartilages T12-L5

• Lesser trochanter

Iliacus • Upper ⅔ of iliac fossa

• Inner lip of iliac crest

• Ant sacroiliac ligament

• Base of sacrum

• lesser trochanter