Quadrilateral Space Syndrome Treated with Ultrasound-Guided Corticosteroid Injection: A Case of Isolated Teres Minor Atrophy and Review of the Literature.

Quadrilateral space syndrome (QSS) is a rare orthopedic condition caused by compression, entrapment, or injury to the axillary nerve or posterior humeral circumflex artery as they arise from the quadrilateral space. QSS can present with point tenderness over the quadrilateral space and weakness and paresthesia in the axillary nerve distribution. It is commonly associated with repetitive overhead activities and is seen in athletes engaging in such activities. Here we report a case of QSS in a 42-year-old male weight lifter who presented with pain and soreness in the posterior aspect of his right shoulder radiating around his arm as well as slight weakness of his right shoulder of a few weeks duration. MRI results of his shoulder demonstrated moderate atrophy and fatty infiltration of the teres minor. His diagnosis of QSS was confirmed with electro diagnostic testing which showed axillary neuropathy. He was treated with ultrasound guided corticosteroid injections and gained relief from this treatment. His axillary neuropathy was shown to be resolving on repeat electro diagnostic testing at six-months follow-up. Here we report a case of QSS and provide a brief review of the literature.