Muscles of the Lumbar Spine

Question 1

Exteneral oblique

Answer 1

O: outer surfaces of ribs 5-12 and costal cartilages
I: linea alba,
pubic tubercles to ASIS
anterior 2/3 iliac crest
I: anterior rami of T7-T12
A: flexion of trunk, rotation, lateral flexion

Question 2

Internal oblique

Answer 2

O: lateral 2/3 of inguinal ligament, anterior 2/3 of iliac crest, thoracolumbar fascia
I: lower borders of ris 10-12, linea alba, pectin pubis
I: L1 nerve, anterior rami of T7-T12
A: posterior pelvic tilt
flexion, rotation and lateral fleixion of the trunk

Question 3

Transverse Abdominus

Answer 3

O: internal surfaces of 7th-12th costal cartilages, thoracolumbar fascia, ilaic crest and lateral 1/3 of inguinal ligament
I: linea alba, pectin pubis
I: l1 nerve, anterior rami T7-T12
A: raises intra abdominal pressure, stabilises lumbar spine

Question 4

Rectus Abdomius

Answer 4

O: pubic symphysis, pubic crest
I: Xiphoid process, 5th-7th costal cartilages
I: anterior rami of t6/t7-T12
A: flexion of trunk, rotation and lateral flexion of trunk

Question 5

Quadratus lumborum

Answer 5

O: iliolumbar ligament
iliac rest
I: TP of first lumbar vertebrae, middle 1/2 of inferoir border of 12th rib
I: anterior rami of T12 and L1 to L4
A: ipsilateral side flexion, extension, stabilise 12th rib on inspirtaion

Question 6

What does th posterior abdomindal wall consist of?

Answer 6

psoas major
iliacus
quadratus lumborum
diaphragm