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| Muscle | Origin | Insertion | Action | Nerve |
| diaphragm | vertebral: crura from bodies of L1, 2 (left), L1-3 (right); costal part: medial & lateral arcuate ligaments, inner aspect of lower six ribs; sternal: two slips from post aspect of xiphoid | central tendon of diaphragm (dome of diaphragm) | inspiration (increases thoracic cavity volume); assists in raising intra-abdominal pressure (valsalva maneuver) | phrenic nerve (C3, C4, C5) |
| external abdominal oblique | anterior 1/2 of iliac crest, inguinal ligament, public tubercle/crest, & abdominal aponeurosis (rectus sheath) | inferior border of ribs #5-12 | flexion, lateral flexion & contralateral rotation of trunk (at spinal joints); posterior pelvic tilt (at spinal joints); compression/stabilization of abdomen | intercostal nerves (T7-T12) |
| illiacus | inner surface of upper iliac fossa & sacral ala | lesser trochanter of femur (via iliopsoas tendon) | flexion & lateral rotation of thigh (at hip); anterior pelvic tilt | femoral nerve (L2, L3) |
| internal abdominal oblique | iliac crest, inguinal ligament, thoracolumbar fascia | ribs #10-12 & abdominal aponeurosis (rectus sheath) | flexion, lateral flexion & ipsilateral rotation of trunk (at spinal joints); posterior tilt of pelvis (at lumbosacral joints); compression/stabilization of abdomen | intercostal nerves (T7-L1) |
| psoas major | TPs of L1-L5, vertebral bodies of T12-L5 & intervening intervertebral discs | lesser trochanter of femur (via iliopsoas tendon) | flexion & lateral rotation of thigh (at hip); flexion & lateral flexion of trunk (at spinal joints); anterior pelvic tilt (at hip joint) | lumbar plexus ventral rami (L1, L2, L3) |
| psoas minor | vertebral bodies of T12 & L1 & intervening intervertebral disc | pectineal line of pubis & iliopubic eminence | flexion of trunk (at spinal joints); posterior pelvic tilt (at spinal joints) | ventral rami of L1 |
| pyramidalis | pubic crest (anterior to origin of rectus abdominis) | lower linea alba | tension of linea alba (reinforces lower rectus sheath) | subcostal nerve (T12-L1) |
| rectus abdominis | pubic crest & pubic symphysis | costal cartilage of ribs #5-7 & xyphoid process | flexion of trunk (at spinal joints); posterior pelvic tilt (at spinal joints); compression/stabilization of abdomen | intercostal nerves (T5-T12) |
| transversus abdominus | iliac crest, inguinal ligament, thoracolumbar fascia & lower costal cartilage | abdominal aponeurosis (rectus sheath) | compression/stabilization of abdomen | intercostal nerves (T7-L1) |
Vertebral Column