INFRASPINATUS PARALYSIS DUE TO SPINOGLENOID NOTCH GANGLION

We describe five patients, seen since 1984, with posterior shoulder pa in and isolated wasting and weakness of the infraspinatus. In four of these a ganglion in the spinoglenoid notch was demonstrated by MRI and in one recent case ultrasound scans were positive. Three patients hav e been treated by operation, but there was recurrence in one after fiv e years. In each confirmed case, the ganglion straddled the base of th e spine of the scapula, extending into both supraspinatus and infraspi natus fossae. The nerve was either compressed against the spine or str etched over the posterior aspect of the ganglion. Adequate surgical ex posure is essential to preserve the nerve to the infraspinatus and to allow complete removal of the ganglion. This is difficult because of t he location and thin-walled nature of the cysts.