Muscles of the Abdomen

Question 1

External Oblique

Answer 1

• Lower 8 ribs

• Iliac crest
• Linea alba
• Pubic tubercle
• Trunk: Flexion, IL lateral flexion, CL rotation
• Compression of abdomen
• Spine stabilization
• Posterior pelvic tilt

• Anterior primary rami (APR) T7-T12

Question 2

Internal Oblique

Answer 2

• Thoracolumbar fascia
• iliac crest
• inguinal ligament
• Lower 3 ribs
• linea alba
• pectineal line
• pubic crest
• Trunk: Flexion, IL lateral flexion, IL rotation
• Compression of abdomen
• Spine stabilization
• Posterior pelvic tilt

• APR T7-T12; L1

Question 3

Transversus abdominis

Answer 3

• Thoracolumbar fascia
• iliac crest
• inguinal ligament
• Lower 6 ribs
• linea alba
• pectineal line
• pubic crest
• Compression of abdomen
• Spine stabilization
• Assists with breathing

• APR T7-T12; L1

Question 4

Rectus Abdominis

Answer 4

• Pubic crest
• tubercle
• symphysis
• Ribs 5-7
• xiphoid process
• Flex trunk
• compress abdomen
• posterior pelvic tilt

• APR T7-T12

Question 5

Cremaster

Answer 5

• Internal oblique
• Spermatic cord
• Pulls testis upward
• Genital branch of genitofemoral n.(L1-L2)

Question 6

Psoas major

Answer 6

• TPs,
• vertebral bodies
• IVDs of T12-L5

• Lesser trochanter

• Hip flexion and ER
• Trunk flexion

• APR L1-L3

Question 7

Psoas minor

Answer 7

• Vertebrae T12-L1
• Pectineal line
• Posterior pelvic tilt
• Weak trunk flexion

• APRL1

Question 8

Iliacus

Answer 8

• Iliac fossa
• Lesser trochanter

• Hip flexion and ER
• Anterior pelvic tilt with
stabilization of legs

• Femoral n. (L2-3)

Question 9

Quadratus lumborum

Answer 9

• Iliac crest
• Iliolumbar ligament
• Rib 12
• TPs of L1-L4
• Lateral trunk flexion
• Stabilize rib 12

• APR T12-L4

Question 10

Diaphragm

Answer 10

• Xiphoid process
• Costal cartilage ribs 7-12
• Lumbar vertebrae/ IVDs

• Central tendon

• Contracts during inhalation
• Relaxes during exhalation

• Phrenic n. (C3-C5)