Muscles

Question 1

External Oblique - Location, Structure, Function

Answer 1

Location: Superficial muscle of the anterior abdominal wall
Structure: Flat, skeletal muscle, fibres run in an inferomedial direction and forms an aponeurosis medially
Function: Flexion + rotation of trunk to contralateral side, compression + support of abdominal viscera

Question 2

Internal Oblique - Location, Structure, Function

Answer 2

Location: Intermediate muscle of the anterior abdominal wall
Structure: Flat, fan shaped, skeletal muscle. Fibres run horizontally at the level of the ASIS, obliquely upward superior to the ASIS, and obliquely downward inferior to the ASIS.
Function: Flexion + rotation of trunk to ipsilateral side, compression + support of abdominal viscera.

Question 3

Transverse Abdominal - Location, Structure, Function

Answer 3

Location: Innermost muscle of the anterior abdominal wall
Structure: Flat, skeletal muscle. Fibres mostly run transversomedially, the inferior fibres run parallel to the fibres of the internal oblique.
Function: Compression + support of abdominal viscera

Question 4

Rectus Abdominis - Location, Structure, Function

Answer 4

Location: Superficial muscle of the anterior abdominal wall
Structure: Vertical, skeletal muscle. Most of the muscle is enclosed within the rectus sheath.
Function: Flexes trunk, compression + support of abdominal viscera.

Question 5

External Oblique - Origin, Insertion, Nerve Supply

Answer 5

Origin: External surfaces of ribs 5-12
Insertion: Linea alba, pubic tubercle, ant. ½ iliac crest
Nerve Supply: Thoracoabdominal nerves (ventral rami inf. 6 thoracic nn) + subcostal nerve

Question 6

Internal Oblique - Origin, Insertion, Nerve Supply

Answer 6

Origin: Thoracolumbar fascia, ant. 2/3 iliac crest, lat. 1/2 inguinal ligament.
Insertion: Inferior borders of ribs 10-12, linea alba, pectineal line via conjoint tendon.
Nerve Supply: Thoracoabdominal nerves (ventral rami inf. 6 thoracic nns) + first lumbar nerve.

Question 7

Transverse Abdominal - Origin, Insertion, Nerve Supply

Answer 7

Origin: Inferior surfaces of costal cartilages 7-12, thoracolumbar fascia, iliac crest, lateral 1/3 of inguinal ligament.
Insertion: Linea alba with aponeurosis of internal oblique, pubic crest + pectineal line via conjoint tendon.
Nerve Supply: Thoracoabdominal nerves (ventral rami inf. 6 thoracic nn) + first lumbar nerve

Question 8

Rectus Abdominis - Origin, Insertion, Nerve Supply

Answer 8

Origin: Pubic symphysis + pubic crest.
Insertion: Xiphoid process + costal cartilages 5-7
Nerve Supply: Thoracoabdominal nerves (ventral rami of inf. 6 thoracic nn)