[Selective paralysis of the infraspinatus muscle, caused by compression of the infraspinatus branch of the supraspinatus muscle].

This is the case of a thirty-year-old athlete suffering from a painful right shoulder while moving and working with his right arm and showing a massive atrophy of his right infraspinatus muscle. After careful examination an isolated compression of the inferior branch of the suprascapular nerve was suspected. The entrapment of the nerve at the spinoglenoid notch by a large and hypertrophied ligament was demonstrated by an open revision.