Obturator Nerve Flashcards

Follow the obturator nerve from the lumbar plexus through the pelvis to the medial thigh, examining its branches, muscle supply, and clinical anatomy.

Card 1 of 28Question

Which spinal nerve roots form the obturator nerve?

The anterior rami of L2, L3, and L4.

In This Section

1. Which spinal nerve roots form the obturator nerve?

The anterior rami of L2, L3, and L4.

2. From which nerve plexus does the obturator nerve arise?

The lumbar plexus.

3. Which divisions of the lumbar plexus form the obturator nerve?

The anterior divisions of the anterior rami of L2 to L4.

4. Where does the obturator nerve emerge from the psoas major muscle?

At the medial border of psoas major.

5. How does the obturator nerve travel through the pelvis?

It descends along the lateral pelvic wall toward the obturator canal.

6. Which major pelvic blood vessels does the obturator nerve pass posterior to near the pelvic brim?

The common iliac vessels.

7. Through which opening does the obturator nerve leave the pelvis?

The obturator canal.

8. Which blood vessels accompany the obturator nerve through the obturator canal?

The obturator artery and vein.

9. What are the two principal terminal divisions of the obturator nerve?

The anterior and posterior divisions.

10. Which muscle typically separates the anterior and posterior divisions of the obturator nerve?

The adductor brevis muscle.

11. Between which muscles does the anterior division of the obturator nerve usually descend?

Between adductor longus anteriorly and adductor brevis posteriorly.

12. Between which muscles does the posterior division of the obturator nerve usually descend?

Between adductor brevis and adductor magnus.

13. Which muscles are typically innervated by the anterior division of the obturator nerve?

Adductor longus, gracilis, and usually adductor brevis, with variable supply to pectineus.

14. Which muscles are typically innervated by the posterior division of the obturator nerve?

Obturator externus and the adductor portion of adductor magnus.

15. Which part of adductor magnus is supplied by the obturator nerve?

The adductor portion, also called the pubofemoral portion.

16. Which nerve supplies the hamstring portion of adductor magnus instead of the obturator nerve?

The tibial division of the sciatic nerve.

17. What is the principal motor function of the obturator nerve?

Adduction of the thigh at the hip joint.

18. Which muscle supplied by the obturator nerve contributes to lateral rotation of the thigh?

The obturator externus muscle.

19. What is the typical cutaneous distribution of the obturator nerve?

A small, variable area of skin on the medial thigh.

20. Which division of the obturator nerve usually provides its cutaneous branch?

The anterior division.

21. Which joint receives articular branches from the obturator nerve during its pelvic course?

The hip joint.

22. Which articular branch is commonly supplied by the posterior division of the obturator nerve?

A branch to the knee joint, often accompanying the femoral vessels toward the popliteal region.

23. What is the functional classification of the obturator nerve?

A mixed somatic nerve carrying motor and sensory fibers.

24. What movement is typically weakened following an obturator nerve injury?

Hip adduction, especially against resistance.

25. Which pelvic surgical procedure can place the obturator nerve at risk?

Pelvic lymph node dissection, particularly near the obturator fossa.

26. What clinical condition can result from compression of the obturator nerve within the obturator canal?

Obturator neuropathy, potentially causing medial thigh pain, sensory disturbance, and adductor weakness.

27. How may an obturator hernia produce pain along the medial thigh?

By compressing the obturator nerve within the obturator canal, producing the Howship-Romberg sign.

28. Which anatomical variation may provide additional innervation to the medial thigh muscles?

An accessory obturator nerve, usually arising from L3 and L4.