2.1 Muscles of the Pelvic Limb: Lumbar Hypaxial Muscles (Sub-lumbar)

Lumbar Hypaxial Muscles (Sub-lumbar)

Quadratus lumborum

Psoas minor

Iliopsoas ( psoas major and iliacus)

name the Lumbar Hypaxial Muscles (Sub-lumbar) (3)

Quadratus lumborum

• Origin: arises from the last ribs and from the transverse processes of the lumbar vertebrae;

• Insertion: it inserts on the wings of the Ilium

• Action: to flex and stabilizes the lumbar portion of the vertebral column.

• Innervation: ventral branches of the lumbar nerve

Psoas minor

• Origin: arises from the bodies of the thoracolumbar vertebrae

• Insertion: inserts on the psoas minor tubercle on the ilium

• Action: it may also rotate the pelvis at the sacro-iliac joint.

• Innervation: lateral branches of the rami ventrales of the lumbar nerves 1-4 or 5

Iliopsoas

• fused psoas major and iliacus muscles which act as the chief flexors of the hip joint.

• psoas major and iliacus muscle may be regarded as the vertebral and pelvic head of a single muscle that terminates on the lesser trochanter of the femur

• is a flexor of the hip and an outward rotator of the thigh

• Origin: psoas major - last rib and t-proccess of lumbar vertebrae, iliacus - cranioventral ilium

• Insertion: lesser trochanter of the femur

• Action: to flex the hip

• Innervation: Ventral branches of the lumbar nerves

Psoas major

• strongest flexor of the hip, extending from the lumbar vertebrae caudoventrally with the iliacus muscle to the lesser trochanter of the femur

• Origin: last rib and t-proccess of lumbar vertebrae

• Insertion: lesser trochanter of the femur

• Action: to flex the hip

• Innervation: Ventral branches of the lumbar nerves

Iliacus

• short muscle arising from the ilium, it joins the psoas major to insert on the lesser trochanter of the femur

• Origin: cranioventral ilium

• Insertion: lesser trochanter of the femur

• Action: to flex the hip

• Innervation: Ventral branches of the lumbar nerves