Neuralgic amyotrophy: an increasingly diverse entity.

We describe nine cases of neuralgic amyotrophy whose clinical and electrophysiologic findings suggest lesions of individual peripheral nerves or peripheral nerve branches occurring singly (mononeuropathy) or in various combinations (mononeuropathy multiplex). There were four occurrences of isolated denervation of the pronator teres muscle; four occurrences of anterior interosseous nerve lesions; three occurrences of lateral antebrachial cutaneous nerve lesions; two occurrences of long thoracic nerve lesions; and one occurrence each of a median nerve trunk lesion, a median palmar cutaneous branch lesion, a suprascapular nerve lesion, and an axillary nerve lesion. "Neuralgic" pain was a prominent feature in all cases, and the location of the pain correlated with the location of the nerve lesions. We hypothesize that the specific course of certain nerves (especially their location across joints) selectively exposes them to mild focal trauma that increases their susceptibility to this disease. Whatever the etiology, this entity is considerably more diverse than generally appreciated.