Abdominal Muscles

Question 1

Cremaster

Answer 1

PA: medial edge of the internal oblique
DA: spermatic cord
A: elevation of the testes
Innervation: genitofemoral n.

Question 2

Diaphragm

Answer 2

PA: xiphoid process, inner surface of the lower ribs, costal cartilages, medial & lateral arcuate ligaments, and lumbar vertebrae via the crura
DA: central tendon
A: inspiration (negative thoracic pressure by inferior displacement)
Innervation: phrenic nerve C3-C5

Question 3

External Abdominal Oblique

Answer 3

PA: lower 8 ribs
DA: iliac crest and rectus sheath
A: trunk flexion and rotation, and compression of the abdominal cavity
Innervation: Ventral rami T7-T12

Question 4

Internal Abdominal Oblique

Answer 4

PA: thoracolumbar fascia
DA: inguinal ligament, iliac crest, & rectus sheath
A: trunk flexion and rotation, and compression of the abdominal cavity
Innervation: Lower thoracic & L1 ventral rami T7-T12, L1, iliohypogastric and iliac goin all ventral rami

Question 5

Quadratus Lumborum

Answer 5

PA: 12th rib and transverse processes of L1-L4
DA: iliolumbar ligament and iliac crest
A: trunk lateral flexion and extension, fixes 12th rib during respiration
Innervation: Lumbar plexus ventral rami T12-L3

Question 6

Rectus Abdominis

Answer 6

PA: xiphoid process and adjacent costal cartilages of ribs 5-7
DA: pubic crest and tubercle (symphysis)
A: trunk flexion and compression of the abdominal cavity
Innervation: Lower thoracic ventral rami T5-T12

Question 7

Transversus Abdominis

Answer 7

PA: Lower six costal cartilages and thoracolumbar fascia
DA: inguinal ligament, iliac crest, and, rectus sheath
A: compression of the abdominal cavity
Innervation: Lower thoracic T7-T12, ventral divisions