Quadrilateral space syndrome
What is Quadrilateral space syndrome?
The quadrilateral space is located posterior and inferior to the glenohumeral joint and contains the axillary nerve and posterior humeral circumflex artery. Quadrilateral space syndrome (QSS) is compression of the axillary nerve and posterior humeral circumflex artery as they pass through this space. The pain is characterized clinically by a dull intermittent ache localized in the posterior and lateral shoulder.