Lesion of the anterior branch of axillary nerve in a patient with hereditary neuropathy with liability to pressure palsies

We report the case of a 30-year-old woman affected by hereditary neuropathy with liability to pressure palsies (HNPP), who developed a painless left a xillary neuropathy after sleeping on her left side, on a firm orthopaedic m attress, in her eighth month of pregnancy. Electromyography (EMG) showing n eurogenic signs in the left anterior and middle deltoid, and normal finding s in the left teres minor, posterior deltoid and other proximal upper limb muscles, demonstrated that the lesion was at the level of the axillary ante rior branch. A direct compression of this branch against the surgical neck of the humerus seems the most likely pathogenic mechanism. This is the firs t documented description of an axillary neuropathy in HNPP. Knowledge of it s possible occurrence may be important for prevention purposes.