Lab 5 - Module 2 - Hip and Anterior Thigh - Muscles, Nerves and Vessels: Page 1 of 8

READINGS:

Gray's Anatomy for Students (Fourth Edition): Pages: 558, 581-585, 592-598

Muscles of the Medial Compartment of the Thigh

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Begin with the pelvis and right femur.

Add the Obtruator Externus muscle.

Origin - Margins of obturator foramen and obturator membrane

Insertion - Trochanteric fossa of the femur

Innervation - Obturator Nerve

Action - It laterally rotates the extended hip joint and steadies head of femur in acetabulum

Add the Adductor Magnus muscle.

Origin - Adductor Part: inferior ramus of pubis, ramus of ischium. Hamstring Part: ischial tuberosity

Insertion - Adductor Part: gluteal tuberosity, linea aspera, medial supracondylar line; Hamstring Part*: Adductor tubercle of the femur*Opening in aponeurotic insertion of adductor magnus to the adductor tubercle of the femur called adductor hiatus allows the femoral vessels to pass into the popliteal fossa

Innervation - Adductor Part: Posterior branch of obturator nerve Hamstring Part: Tibial Nerve

Action - Adducts the thigh; Adductor part flexes the thigh; Hamstring part extends the thigh

Add the Gracilis muscle.

Origin - Body and inferior ramus of the pubis

Insertion - Superior part of medial surface of tibia.

Innervation - Obturator Nerve

Action - Gracilis flexes the knee joint, medially rotates the leg when the knee is flexed and adducts the thigh.

Add the Pectineus muscle. It forms part of the posterior wall of the femoral triangle. Iliopsoas lies at its lateral aspect, with adductor longus medially. The femoral vessels and greater saphenous vein lie anteriorly, with the capsule of the hip joint behind its upper aspect.

Origin - Superior ramus of pubis

Insertion - The muscle passes caudal, posterior and laterally, to attach along the pectineal line in between the lesser trochanter and the linea aspera.

Innervation - The femoral nerve, and when present the accessory obturator nerve.

Action - Pectineus adducts and flexes the thigh; assists in medial (internal) rotation of the thigh

Add the Adductor Brevis muscle.

Origin - Body and inferior ramus of pubis

Insertion - Pectineal line and proximal part of the linea aspera of the femur

Innervation - Anterior branch of the obturator nerve

Action - Adducts the thigh

Add the Adductor Longus muscle.

Origin - Body of the pubis inferior to the pubic crest

Insertion - Middle 1/3 of linea aspera of femur

Innervation - Anterior branch of the obturator nerve (L2, 3, 4)

Action - Adducts the thigh

Add the Obturator artery which supplies the medial compartment of the thigh. It is a branch of the internal iliac artery and arises in the pelvic cavity. The obturator artery exits the pelvic cavity through a small opening in the obturator membrane along with the obturator nerve. It divides into anterior and posterior branches, straddling the adductor brevis muscle. Additionally, the posterior branch gives off an acetabular artery that gives rise to the artery to the head of the femur. The femoral artery, as it is passing through the adductor canal contributes to the blood supply of the medial compartment as well as perforating branches from the profunda.

Add the Obturator nerve which is the main motor supply to the muscles of the medial compartment is from the obturator nerve (formed from the anterior divisions of L2, L3, L4 of the lumbar plexus). The nerve exits the pelvic cavity through the obturator foramen and membrane. As it approaches the obturator externus muscle it divides into an anterior and posterior branches like the artery. The posterior branch, typically, pierces through the obturator externus muscle and travels deep to the adductor brevis muscle. The anterior branch, typically, travels over the superior border of the obturator externus muscles and travels superficial to the adductor brevis muscle (deep to the adductor longus muscle). The obturator nerve gives off a cutaneous branch that supply sensory to part of the medial thigh. The main cutaneous innervation of the medial thigh is from the anterior cutaneous branch of the femoral nerve. The ilioinguinal nerve (from the L1 nerve root of the lumbar plexus) provides cutaneous innervation to a small area of the superior medial thigh.