Proximal median mononeuropathies, unrelated to direct trauma or external compression, are unusual in neurophysiological practice; several syndromes have been more commonly described including the anterior interosseus syndrome, the pronator teres syndrome, and entrapments at the lacertus fibrosus or at the ligament of Struthers.1

We report the case of a 29 year old woman with an upper median mononeuropathy at an unusual lesional site. She started a new job consisting of repeatedly lifting heavy crates full of apples from the ground, carrying them for a while, and then putting them on a shelf. Fifteen days later, at the end of a working day, she began to complain of right hand weakness with numbness and tingling limited to the first, second, and third fingers; 4 weeks after the onset of symptoms neurological examination showed marked weakness of thumb abduction and opposition, forearm pronation, and flexion of the wrist and of the distal phalanges of the thumb and index finger; she had paraesthesias on the palmar side of the right thumb, index, and middle fingers without spontaneous pain, which could otherwise be strongly evoked by deep palpation of the median nerve trunk at the lower third of the right upper arm. The patient denied any kind of trauma or prolonged direct compression on that limb.

Electromyography showed fibrillation potentials and neurogenic motor units recruitment in all forearm right median innervated muscles, including the pronator teres; in thenar median innervated muscles abundant fasciculations and severely reduced recruitment patterns were the major findings, with …