Anatomic variations in the long head of biceps: contribution to shoulder dysfunction

Area of Science:

• Orthopedic Surgery
• Anatomy
• Sports Medicine

Background:

• The long head of the biceps (LHB) tendon is increasingly recognized for its significance in shoulder pathologies.
• Advancements in shoulder arthroscopy have heightened interest in the LHB's anatomy and function.
• Standard descriptions of LHB origin are being refined by recent anatomical studies.

Purpose of the Study:

• To review current knowledge regarding anatomical variants of the long head of the biceps tendon.
• To discuss the functional roles of the LHB, including humeral head stabilization and proprioception.
• To propose classification systems for LHB lesions and congenital absence, and outline management strategies.

Main Methods:

• Review of cadaveric studies detailing LHB origin and anatomical variants.
• Analysis of electromyographic, cadaveric, and clinical studies investigating LHB function.
• Inclusion of case experience in treating congenital absence of the LHB tendon.

Main Results:

• The LHB originates from the superior glenoid labrum and supraglenoid tubercle, with variations like the superior sublabral recess and Buford complex.
• Congenital absence of the LHB is a rare variant, with only a few cases previously reported.
• Studies indicate the LHB plays a role in humeral head stabilization and potentially proprioception.

Conclusions:

• Awareness of LHB anatomical variants is essential for accurate diagnosis and effective treatment of shoulder injuries, particularly SLAP tears.
• Proposed classification systems and management guidelines aim to standardize the approach to symptomatic LHB lesions and congenital absence.
• Further understanding of LHB function supports its importance in overall shoulder health and stability.