Muscles - Thigh (Medial Compartment)

Question 1

What are the five muscles of the medial compartment?

What is their actions?

Answer 1

1) Adductor magnus
2) Adductor longus
3) Adductor brevis
4) Obturator externus
5) Gracilis

They adduct the thigh at the hip joint.

Question 2

What nerve and artery supplies the muscles of the medial compartment?

Answer 2

The obturator nerve and artery.

Question 3

Adductor magnus

Answer 3

Functionally, it can be separated into the adductor and hamstring parts.

Origin (adductor part) - ischiopubic rami

Insertion (adductor part) - linea aspera of the femur

Origin (hamstring part) - ischial tuberosity

Insertion (hamstring part) - adductor tubercle and medial supracondylar line of the femur

Actions - both adduct the thigh, but adductor component flexes the thigh, while the hamstring part extends the thigh.

Innervation - adductor part is innervated the obturator nerve (L2-L4) and hamstring part by the tibial part of the sciatic nerve (L4-S3).

Question 4

Adductor longus

Answer 4

Partially covers the magnus and brevis. Forms the medial border of the femoral triangle.

Origin - pubis, expands into a fan shape

Insertion - linea aspera of the femur broadly

Innervation - obturator nerve (L2-L4)

Actions - adduction of the thigh

Question 5

Adductor brevis

Answer 5

Lies underneath the adductor longus.

Lies between the anterior and posterior branches of the obturator nerve.

Origin - body and inferior ramus of pubis.

Insertion - linea aspera

Innervation - Obturator nerve (L2-L4)

Action - Adduction of the thigh

Question 6

Obturator externus

Answer 6

Located superiorly. One of the smaller muscles of the media thigh.

Origin - membrane of the obturator foramen.

Insertion - passes under the neck of the femur and, attaching to the greater trochanter.

Innervation - Obturator nerve (L2-L4)

Actions - Adduction of the thigh at the hip joint and flexion of the lef at the knee.

Question 7

Gracilis

Answer 7

Most superficial and medial muscles of this compartment. Crosses at both the knee and hip joints. Can be transplanted into the hand or forearm to replace a damaged muscle.

Origin - body and inferior rami of the pubis

Insertion - descends vertically down the leg and inserts the medial side of the tibia, between the tendons of sartorius (anteriorly) and semitendinosus (posteriorly).

Actions - adduction of the thigh at the hip, and flexes at the knee joint.

Innervation - Obturator nerve

Question 8

Clinical relevance - damage to the adductor muscles

Answer 8

This is also known as a ‘groin strain’ - proximal part is mostly affected.

Occurs in sports involving explosive movements and extreme stretching.

Treatment - RICE