2.3 Muscles of the Pelvic Limb: Caudal Hip Muscles (Medial Group)

Caudal Hip Muscles (Medial Group)

Internal obturator muscle

External obturator muscle

Gemelli

Quadratus femoris

name the Caudal Hip Muscles (Medial Group) (4)

Internal obturator muscle

• fan–shaped muscle arising medially from the pelvic floor and covering the obturator foramen.

• Its tendon travels over the lesser ischiatic notch to insert in the trochanteric fossa.

• external rotator of the thigh

• Origin: symphysis pelvis

• Insertion: trochanteric fossa

• Action: to rotate the pelvic limb laterally

• Innervation: Sciatic nerve

External obturator muscle

• fan-shaped muscle arising from the ventral surface of the os coxae, covering the obturator foramen externally.

• It inserts in the trochanteric fossa and causes outward rotation of the femur

• Origin: ventral surface of the ischium and pubis

• Insertion: trochanteric fossa

• Action: 

Gemelli

• are two-small twin bundles that passes from the ischial spine to the trochanteric fossa.

• They are also external rotators

• lies deep/under to the tendon internal obturator muscle

• lies in between the quadratus femoris and the external obturator muscle distally and proximally by the deep gluteal muscle

• Origin: lateral surface of the ischium

• Insertion: trochanteric fossa

• Action: to rotate the pelvic limb laterally at the hip joint

• Innervation: Sciatic nerve

Quadratus femoris

• passes from the ventral aspect of the ischium to end on the femoral shaft close to the trochanteric fossa.

• It is described as an extensor but can be of no significance in this role.

• lies between the adductor muscle medially, biceps femoris laterally, external obturator and gemelli dorsally

• Origin: ventral surface of the caudal part of the ischium

• Insertion: trochanteric fossa/intertrochanteric crest of the femur

• Action: to extend the hip and rotate the pelvic limb laterally

• Innervation: Sciatic nerve