Lumbar

Question 1

Quadratus Lumborum

Answer 1

Origin: transverse process of LV vertebra, iliolumbar ligament, and iliac crest

Insertion: transverse processes of L1 to L5 vertebrae and inferior border of rib 12

Innervation: anterior rami of T12 to L4

Function: depress and stabilize rib 12 and ipsilateral lateral flexion of trunk

Question 2

External Oblique

Answer 2

Origin: lower 8 ribs (5 to 12)

Insertion: iliac crest, linea alba

Innervation: anterior rami of T7 to T12

Function: compress abdominal contents; bilateral: flex trunk; unilateral: ipsilateral lateral flexion of the trunk and contralateral rotation of the trunk

Question 3

Internal Oblique

Answer 3

Origin: thoracolumbar fascia; iliac crest between origins of external and transversus; inguinal ligament

Insertion: inferior border of the lower 3 or 4 ribs; linea alba; pubic crest and pectineal line

Innervation: anterior rami of T7 to T12 and L1

Function: compress abdominal contents; bilateral: flex trunk; unilateral: ipsilateral lateral flexion and rotation of the trunk

Question 4

Transverse Abdominis

Answer 4

Origin: thoracolumbar fascia; iliac crest, inguinal ligament, costal cartilages of lower 6 ribs (7 to 12)

Insertion: linea alba, pubic crest and pectineal line

Innervation: anterior rami of T7 to T12 and L1

Function: compress abdominal contents

Question 5

Rectus Abdominis

Answer 5

Origin: pubic crest, pubic tubercle, and pubic symphysis

Insertion: costal cartilages of ribs 5-7; xiphoid process

Innervation: anterior rami of T7 to T12

Function: compress abdominal contents; flex trunk

Question 6

Pyramidalis

Answer 6

Origin: front of pubis and pubic symphysis

Insertion: into linea alba

Innervation: anterior ramus of T12

Function: tenses the linea alba

Question 7

Multifidus

Answer 7

Origin: sacrum, origin of erector spinae, posterior superior iliac spine, mammillary processes of lumbar vertebrae, transverse processes of thoracic vertebrae, and articulate processes of lower 4 cervical vertebrae

Insertion: base of spinous process of all vertebrae from L5 to C2 (axis)

Innervation: posterior rami of spinal nerves

Function: stabilizes vertebrae, extension and ipsilateral lateral flexion of vertebral column

Question 8

Interspinales

Answer 8

Origin: short paired muscles between spinous process of adjacent vertebrae

Insertion:

Innervation: posterior rami of spinal nerves

Function: postural muscles that stabilize adjoining vertebrae during movements of vertebral column

Question 9

Intertransversari

Answer 9

Origin: small muscles between the transverse processes of contiguous vertebrae

Insertion: same as origin

Innervation: posterior rami of spinal nerves

Function: postural muscles that stabilize adjoining vertebrae during movements of vertebral column