Femoral Nerve vs Obturator Nerve
Femoral Nerve vs Obturator Nerve
The femoral and obturator nerves both arise from the lumbar plexus but have distinct anatomical courses and clinical presentations. The femoral nerve supplies the anterior thigh (knee extension, hip flexion), while the obturator nerve supplies the medial thigh (hip adduction).
Comparison Table
Key Differences
- →Femoral = anterior thigh (quadriceps, knee extension); Obturator = medial thigh (adductors)
- →Femoral passes under inguinal ligament; obturator passes through obturator canal
- →Femoral has the important saphenous nerve branch (medial leg sensation)
- →Knee jerk (L3-L4) tests femoral nerve; no equivalent reflex for obturator
Clinical Relevance
- •Femoral nerve palsy: Can't extend knee, difficulty climbing stairs, absent knee jerk
- •Obturator nerve palsy: Weak hip adduction, difficulty keeping legs together
- •Saphenous nerve (branch of femoral) can be injured in varicose vein surgery
- •Both nerves can be injured in pelvic surgery (hysterectomy, hip surgery)
Study Tips
- ✓Femoral nerve mnemonic: "Femoral = Front" of thigh (quadriceps)
- ✓Obturator goes through the Obturator canal to the adductors
- ✓L2-L4 supplies both, but posterior divisions → femoral, anterior divisions → obturator
- ✓Test femoral with straight leg raise; test obturator by squeezing legs together
FAQs
Common questions about this comparison
The femoral sheath is a continuation of the transversalis fascia and iliac fascia that encloses the femoral vessels. The femoral nerve lies in a separate fascial compartment between the iliacus and psoas muscles, lateral to the sheath, so it is not enclosed within it.
Obturator hernia is a rare hernia through the obturator canal. It typically occurs in elderly, thin women. The hernia can compress the obturator nerve as it passes through the canal, causing medial thigh pain (Howship-Romberg sign) and adductor weakness.