Which nerve is most commonly injured in pelvic fractures causing medial thigh sensory loss?

Which nerve is most commonly injured in pelvic fractures causing medial thigh sensory loss?

• A. Femoral nerve
• B. Sciatic nerve
• C. Genitofemoral nerve
• D. Obturator nerve

Answer: (D)

The main concept is the distribution of the obturator nerve and its vulnerability in pelvic injuries. The obturator nerve arises from L2–L4 and travels through the pelvic cavity along the lateral wall, then exits via the obturator canal to reach the medial thigh. It provides sensation to the medial aspect of the thigh and motor to the adductor muscles. Because it runs through the pelvic region near the pubic bones and the obturator canal, pelvic fractures can easily injure it, leading to sensory loss on the medial thigh along with potential weakness in thigh adduction. The other nerves don’t typically produce isolated medial thigh sensory loss. The femoral nerve mainly covers the anterior thigh and the medial leg via the saphenous nerve; injury presents with weakness of hip flexion and knee extension and sensory loss in the anterior thigh and medial leg. The sciatic nerve supplies the posterior thigh and all of the leg, so injury there would affect the posterior thigh and distal leg rather than the medial thigh. The genitofemoral nerve provides sensation to a small region of the proximal anterior thigh and cremasteric function, not the medial thigh region. Thus, the nerve most commonly injured in pelvic fractures causing medial thigh sensory loss is the obturator nerve.

The main concept is the distribution of the obturator nerve and its vulnerability in pelvic injuries. The obturator nerve arises from L2–L4 and travels through the pelvic cavity along the lateral wall, then exits via the obturator canal to reach the medial thigh. It provides sensation to the medial aspect of the thigh and motor to the adductor muscles. Because it runs through the pelvic region near the pubic bones and the obturator canal, pelvic fractures can easily injure it, leading to sensory loss on the medial thigh along with potential weakness in thigh adduction.

The other nerves don’t typically produce isolated medial thigh sensory loss. The femoral nerve mainly covers the anterior thigh and the medial leg via the saphenous nerve; injury presents with weakness of hip flexion and knee extension and sensory loss in the anterior thigh and medial leg. The sciatic nerve supplies the posterior thigh and all of the leg, so injury there would affect the posterior thigh and distal leg rather than the medial thigh. The genitofemoral nerve provides sensation to a small region of the proximal anterior thigh and cremasteric function, not the medial thigh region.

Thus, the nerve most commonly injured in pelvic fractures causing medial thigh sensory loss is the obturator nerve.