Ectopic insertion of the pectoralis minor muscle with tendinosis as a cause of shoulder pain and clicking.

摘要

In the majority of patients, the pectoralis minor tendon inserts on the coracoid process. In ectopic or anomalous insertions, it can attach to the coracoacromial ligament, the supraspinatus, the capsule of the glenohumeral joint, the tubercles of the humeral head, or the glenoid labrum. Although ectopic insertions have been described since 1897, they are usually thought to be clinically insignificant. In most of the clinically symptomatic cases reported, the ectopic insertion was discovered at surgery or arthroscopy, and preoperative imaging did not depict the anatomical anomaly. We describe a symptomatic patient where the ectopic insertion of the pectoralis minor on the supraspinatus muscle was demonstrated on magnetic resonance imaging (MRI) arthrogram and ultrasound of the shoulder.