Isolated and painless infraspinatus atrophy in top-level volleyball players. Report of two cases and review of the literature.

Isolated and painless infraspinatus atrophy and weakness are described in two top-level volleyball players. EMG revealed isolated denervation of the infraspinatus muscle. One athlete continued playing and his clinical features have not changed. The other recovered her muscle bulk and strength after stopping playing. These findings were attributed to intense activity of the shoulder joint, without any direct trauma. On clinical grounds, we did not consider these cases as true examples of entrapment neuropathy. Pathogenesis was related to traction of the distal branch of the suprascapular nerve during the act of reception of the ball ("Manchete").