Introduction:
Early studies on human embryology reveal a migration of the tendon of long head of biceps from the synovium and fibrous capsule to an intra-articular position [1, 2, 3]. Any hindrance in the normal course of events of development, pathological or otherwise, may result in variations from the normal anatomy.
Case report:
Here, we discuss a case of a rare anatomical variant of the origin of long head of biceps tendon discovered incidentally in a 30-year-old manual laborer. The patient had an insidious onset and gradually progressive right shoulder pain, especially in initiating abduction, with a feeling of instability for 5 months. On examination, apprehension test and anterior drawer test were present and sulcus sign was positive. Partial-thickness supraspinatus tear and fraying of the anteroinferior glenoid labrum were noted in the imaging. After giving a fair trial of conservative management, the patient was posted for an arthroscopic repair of the supraspinatus tear and the anteroinferior glenoid labrum when the anomalous origin of the tendon of long head of biceps was discovered incidentally. This origin was from the inferior surface of the supraspinatus muscle outside the capsule. The tendon was left intact as it was not found to be inflamed or degenerated and was not the source of instability.
Conclusion:
Due to the rarity of this anatomical variant, definite conclusions cannot be drawn currently regarding its pathological nature. Shoulder arthroscopists should be aware of its potential to become abnormally thickened and causing shoulder dysfunction.