The Obturator Nerve

Question 1

What are the nerve roots of the obturator nerve?

Answer 1

L2-L4

Question 2

What is the motor function of the obturator nerve?

Answer 2

Innervates the medial (adductor) compartment of the thigh.

Question 3

What muscles are in the medial compartment and what are their functions?

Answer 3

Adductor Longus- Adducts the thigh
Adductor Brevis- Adducts the thigh
Adductor Magnus- Adductor part adducts and flexes thigh, hamstring part extends thigh
Gracilis- Adducts thigh
Obturator Externus- Laterally rotates thigh

Question 4

What is odd about one of the muscles within the medial compartment?

Answer 4

The hamstring part of adductor Magnus is innervated by the tibial nerve, not the obturator nerve.

Question 5

What area of the lower limb does the obturator nerve supply? (Sensation)

Answer 5

The cutaneous branch of the obturator nerve supplies the skin of the middle part of the medial thigh.

Question 6

What is the anatomical course of the Obturator nerve pre-division?

Answer 6

• Descends through the fibres of psoas major and emerges from its medial border.
• It runs posteriorly to the common iliac arteries and laterally along the pelvic wall to the obturator foramen.
• It enters the thigh through the obturator canal and splits into anterior and posterior divisions.

Question 7

What is the anatomical course of the anterior division of the obturator nerve?

Answer 7

• Descends between the adductor longus and adductor brevis towards the femoral artery.
• It gives off branches to the adductor longus, braves and gracilis muscles.
• It then pierces the fascia late to become the cutaneous branch of the obturator nerve.