Muscles of the Abdominal Wall

Question 1

Diaphragm

Answer 1

O: deep surface of xiphoid process + lower ribs anteriorly/laterally + bodies of upper lumbar vertebrae + fascia over psoas major and quadratus lumborum

I: central tendon of the diaphragm

A: depression of the central tendon to increase vertical dimension of thoracic cavity

In: phrenic nerve (C3, C4, C5)

Question 2

External Oblique

Answer 2

O: lower 6 ribs

I: anterior part of iliac crest + pubis + aponeurosis into linea alba

A: with internal oblique + transverse abdominis: compression of abdominal cavity, flexion + rotation of the trunk

Question 3

Internal Oblique

Answer 3

O: iliopsoas fascia + inguinal ligament, anterior part of iliac crest, thoracolumbar fascia

I: aponeurosis into linea alba, lower ribs

A: compression of abdominal cavity

In: lower intercostals nerces, iliohypogastric and ilioinguinal nerves

Question 4

Transversus Abdominis

Answer 4

O: thoracolumbar fascia, tips of lower 6 ribs, anterior part of iliac crest, iliopsoas fascia and inguinal ligament

I: aponeurosis into linea alba

A: compression of abdominal cavity

In: lower intercostals neres, iliohypogastric and ilioinguinal nerves

Question 5

Rectus Abdominis

Answer 5

O: pubic crest, ligaments of the pubic symphysis

I: xiphoid process, ribs 5-7

A: flexion of the trunk

In: lower intercostals nerces

Question 6

Quadratus Lumborum

Answer 6

O: medial part of iliac crest

I: rib 12 + lower lumbar vertebrae

A: lateral action of vertebral column + fixes last rib to form a stable base for diaphragm contraction

In: branches from T12 and L1 and L3

Question 7

Psoas Major

Answer 7

O: bodies + transverse processes of lumbar vertebrae (possibly also T12)

I: lesser trochanter of femur

A: flexion of thigh, slight adduction of thigh

In: femoral nerve