Ans. D: All of the above Foot drop may follow direct injury to the dorsiflexors. A few cases of rupture of the tibialis anterior tendon leading to foot drop and suspicion of peroneal nerve palsy have occurred. This subcutaneous tendon rupture usually occurs after a minor trauma with the foot in plantar flexion. Compament syndromes also may lead to foot drop. March gangrene, a form of anterior compament syndrome, is thought to be due to edema and small hemorrhages in the muscles of the anterior compament occurring after strenuous activity in individuals not accustomed to it. Deep posterior compament syndrome also may result in foot drop as a late sequela due to resultant contracture formation. Neurologic causes of foot drop include mononeuropathies of the deep peroneal, common peroneal, or sciatic nerves. Lumbosacral plexopathy, lumbar radiculopathy, motor neuron disease, or parasagittal coical or subcoical cerebral lesions also can manifest as foot drop. These lesions can be differentiated through clinical and electrodiagnostic examinations. A common behavioral cause of foot drop is habitual crossing of the legs. These cases typically resolve with discontinuation of the habit. Foot drop also may be seen as a combination of neurologic, muscular, and anatomic dysfunction. Charcot foot is one example.