Abdominal wall muscles

Question 1

What is the origin, insertion, nerve supply and actions of the external oblique muscles

Answer 1

Origin
- outer surface of the lowest eight ribs

Insertion
- anterior 2/3 of the outer lip of the iliac crest
- linea alba
- pubic tubercle
- pubic crest
- ASIS

Nerve supply
- ventral rami of the lower 6 thoracic nerves (T7-T12)

Actions
- contains the abdominal viscera, amy contract to raise intra-abdominal pressure
Move trunk to one side

Question 1

What are the origins, insertion and nerve supply of the internal oblique muscle?

Answer 1

Origin
- thoracolumbar fascia
- anterior 2/3 of the iliac crest
- lateral 2/3 of the inguinal ligament

Insertion
- cartilages of the lower 3 ribs
- conjoint tendon
- pubic crest
- linea alba

Nerve supply
- lower 6 thoracic nerves (T7-T12)
- iliohypogastric and ilioinguinal nerve

Question 2

What are the boundaries of the inguinal canal?

Answer 2

Roof
- Internal oblique muscle
- transversus abdominis muscle

Anterior wall
- external oblique aponeurosis
- internal oblique aponeurosis

Floor
-Inguinal ligament
- lacunar ligament

Posterior wall
- transversalis fascia
- conjoint tendon

Laterally
- internal ring, transversalis fascia and fibres of internal oblique

Medially
- external ring
- conjoint tendon