Background: Functional stability and biomechanics of the shoulder depend on the interaction of both static and dynamic-stabilizing structures. Static stabilizers include the bony anatomy, negative intra-articular pressure, the glenoid labrum, and the glenohumeral ligaments along with the joint capsule. The dynamic stabilizing structures include the rotator cuff muscles and other muscular structures surrounding the shoulder joint. Purpose: Using review of literature in order to understand the role of the long head of the biceps in shoulder kinematics. Methods: We used descriptive method for literature review. The PubMed electronic database was searched from year 2000 to 2016. Results: Thirteen studies were included. Six of them studied the effect of the long head of the biceps on arthrokinematics, for effect on rotational range of motion and five studies researched activity of the long head of the biceps and whole biceps during shoulder movement. Discussion and conclusion: Studies on cadavers show limitation of humeral head translations in all directions after loading the long head of the biceps, however these studies assume activity in muscle of the long head of the biceps and do not assume activity changes in other muscles around the joint. Therefore its actual influence on arthrokinematics in vivo is questionable. Loading the long head of the biceps in abduction (more than 45⁰) limits external and internal rotation in cadavers. Electromyography studies on activity of the long head of the biceps and the whole biceps in shoulder flexion movement are contradicted. Biceps brachii is most active in throwing sports during arm deceleration, slightly less during arm cocking. Patients with anterior shoulder instability and rotator cuff tears have higher activity in biceps. The long head of the biceps helps depress shoulder in rotator cuff tears patients than in healthy people.
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