Oplique and Rectus Muscles: Anterior

Question 1

Rectus Abdominis

Answer 1

Origin: Pubic crest, pubic symphysis
Insertion: Pubis, cartliages of ribs 5-7, xiphoid process
Action: Flexion of spine, compression of abdominal viscera
Innervation: Spinal nerves (T7-T12)

Question 2

External Oblique

Answer 2

Origin: Sternum, ribs (5-12)
Insertion: Linea Alba, Iliac crest
Action: Bilaterially: flexion of spine, compresses abdomen. Unilaterially flexes trunk to same side, rotates to opposite side.
Innervation: Lower intercostal, ilioinguinal nerves

Question 3

Internal Obliques

Answer 3

Origin: Iliac crest, lumbodorsal fascia
Insertion: Inferior ribs, linea alba
Action: Compresses abdomen, depresses ribs, flexes spine
Innervation: Lower intercostal, ilioinguinal nerves

Question 4

Transverse abdominis

Answer 4

Deep to internal oblique
Origin: Lateral inguinal ligament, inner iliac crest.
Insertion: Linea alba, pubis
Action: Compression of abdomen
Innervation: First lumbar nerve (T7-L1), iliohypogastric (T12-L1), ilioinguinal (T12-L1)