Muscles of pelvic girdle

Question 1

Mm. of pelvic girdle

Answer 1

(medial–> lateral)

M. psoas minor
M. iliopsoas
M. quadratus lumborum

Question 2

M. psoas minor

Answer 2

o Origin: bodies of last few thoracic and 1-5th lumbar vertebrae; mainly tendinous

o Insertion: arcuate line of iliac bone, near to iliopubic eminence

o Action: If vertebral column is fixed: draws pelvis into a deeper position.
When pelvis is fixed: arches lumbar region and flexes vertebral column

Question 3

M. iliopsoas

Answer 3

It has two parts: m. psoas major and m. iliacus medialis et lateralis

o Origin: m. psoas major starts ventrally from bodies and transverse processes of lumbar vertebrae, the two m. iliacus arising between arcuate line and lateral border of iliac bone

o Insertion: together on trochanter minor of femur (medially)

oAction: draws pelvic limb forward by flexing the hip; when femur is fixed: flexion and fixation of vertebral column

Question 4

M. quadratus lumborum

Answer 4

o Origin: 11-13th thoracic vertebra ventrally, last two ribs, lumbar vertebra’s transverse processes

o Insertion: medial surface of iliac wing (between articular surface and cranial ventral iliac spine of tuber coxae)

o Action: fixation and dorsal flexion of vertebral column