A rare case of an anatomical variation of bilateral long head of the biceps brachii tendons identified within the substance of bifid subscapularis tendons.

The long head of the biceps tendon is stabilized in the intertubercular groove by several anatomical structures. Dislocation or identification of the biceps tendon into or within the subscapularis tendon is very rarely mentioned in the literature. This is the first reported case of bilateral identification of the long head of the biceps tendons within the lateral subscapularis tendon. This report presents the case of a 51-year-old male patient who presented for bilateral shoulder pain. After failure of conservative treatment, MRIs were done which identified bilateral biceps tendons within the subscapularis tendons, with a concomitant supraspinatus tear on the right side. He underwent right shoulder arthroscopic biceps tenotomy, with supraspinatus repair. The symptoms of the left shoulder diminished as a result of the continuation of conservative treatment. The long head of the biceps tendon normally travels through the intertubercular groove and is stabilized by soft tissue and bony structures. Medial dislocation of the tendon is affected by the medial wall angle and by the integrity of the soft tissue stabilizers; most importantly the coracohumeral ligament in the proximal part of the groove. Dislocation of the biceps tendon into the substance of the subscapularis has been rarely mentioned in the literature; and as far as we know, bilateral occurrence without any identifiable subscapularis tears has never been previously mentioned. The bilateral occurrence with the absence of subscapularis lesions indicates that this is a congenital anomaly.