ABSTRACT

The cubital tunnel is a fibro-osseous groove bounded anteriorly by the medial epicondyle and laterally by the olecranon and the ulnohumeral ligament. The me­ dial boundary of the groove is covered by a fibroaponeurotic band which in the normal state is loose and permits longitudinal gliding of the nerve with elbow flex­ ion and extension. Compression at this site can be due to several factors grouped into three categories: conditions within the groove (fracture fragments, arthritic spurs, hypertrophic bone, and ganglia), factors outside the groove (external compression, or presence of an anomalous anconeus epitrochlearis muscle), and conditions which predispose the nerve to displacement outside the groove during elbow flexion (con­ genital laxity of the fibroaponeurotic covering over the epicondylar groove, or a traumatic tear in the covering).