Abdominopelvic muscles

Question 1

Diaphragm

Answer 1

Origin and Insertion: L1-3, lower 6 ribs

Action: Pulls central tendon inferiorly

Innervation: Phrenic nerve

Question 2

Quadratus lumborum

Answer 2

Origin: Rib 12

Insertion: Lumbar transverse process, iliac crest

Action: ipsilateral lateral flexion

Innervation: thoracolumbar ventral rami

Question 3

External oblique abdominal

Answer 3

Origin: Posterior lower 8 ribd

Insertion: Linea alba and iliac crest

Action: Trunk flexion (Bilateral) and contralateral rotation (unilateral)

Innervation: Lower thoracic ventral rami

Question 4

Internal oblique abdominal

Answer 4

Origin: lower 4 ribs, linea alba

Insertion: Anterolateral iliac crest, inguinal ligament

Action: Trunk flexion (Bilateral) and ipsilateral rotation (unilateral)

Innervation: Lower thoracic ventral rami + L1

Question 5

Transverse abdominis

Answer 5

Origin: Internal lower ribs and thoracolumbar fascia

Insertion: Linea alba and iliac crest, inguinal ligament

Action: increase intra-abdominal pressure

Innervation: Lower thoracic ventral rami + L1

Question 6

Rectus Abdominis

Answer 6

Origin: Xyphoid process, adjacent costal cartilage

Insertion: Pubic crest and symphysis

Action: Trunk flexion

Innervation: Thoracic ventral rami

Question 7

Coccygeus

Answer 7

Origin: Ischial spine, sacrospinous ligament

Insertion: Inferior sacrum and coccyx

Action: Supports pelvic viscera

Innervation: Ventral rami lower sacral nerves

Question 8

Levator Ani

Answer 8

Origin: Body of pubis, arch of obturator fascia, ischial spine

Insertion: Perineal body, coccyx

Action: Supports pelvic viscera and raises pelvic floor

Innervation: Ventral rami of lower sacral nerves