Subclavius Tendon

tendo musculi subclavii

The subclavius tendon attaches the subclavius muscle to the inferior surface of the middle third of the clavicle, in the groove for the subclavius muscle. The muscle belly arises via a short fleshy origin from the first rib and its costal cartilage junction, and its insertion tendon runs laterally to the clavicular groove. The tendon and muscle lie between the clavicle superiorly and the subclavian vessels and brachial plexus inferiorly.

Region: Chest

Clinical Relevance

Clinical Notes

The subclavius tendon and its bony attachment are relevant in clavicle fracture management: subclavius contraction holds the medial clavicular fragment inferiorly, contributing to the typical clavicle fracture displacement pattern. The subclavius muscle and its tendon form a protective layer between the clavicle and the subclavian vessels and brachial plexus, providing some degree of protection to these structures in clavicle fractures. Release of the subclavius tendon is sometimes performed during thoracic outlet decompression surgery.

Pathology

Common Injuries & Conditions

Subclavius Strain

Rare strain of the subclavius muscle and tendon from weightlifting or direct shoulder impact produces pain directly under the clavicle worsened by shoulder abduction and arm elevation, managed conservatively and often underdiagnosed as acromioclavicular or glenohumeral pathology.