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Transverse humeral ligament

The transverse humeral ligament (THL) is a short, fibrous band that spans across the intertubercular (bicipital) groove of the humerus. It converts the groove into a tunnel and stabilizes the long head of the biceps brachii tendon, preventing anterior or medial displacement during shoulder movement.

Although small, the THL is functionally significant as part of the bicipital pulley system, working alongside the subscapularis and supraspinatus tendons to maintain biceps tendon alignment. Its integrity is important in shoulder stability, overhead activity, and prevention of biceps tendon subluxation.

Synonyms

  • Humeral transverse ligament

  • Bicipital pulley ligament

  • Intertubercular ligament

Location and Structure

  • Position: Lies horizontally across the bicipital groove between the greater and lesser tubercles of the humerus.

  • Composition: Dense fibrous connective tissue continuous with the subscapularis tendon, coracohumeral ligament, and supraspinatus fibers.

  • Shape: Short, band-like reinforcement over the long head of biceps tendon.

  • Functionally connected to: Rotator interval structures and glenohumeral ligaments.

Relations

  • Deep: Long head of biceps brachii tendon within the bicipital groove

  • Superior: Subscapularis and supraspinatus tendon insertions

  • Inferior: Proximal humeral shaft

  • Lateral: Greater tubercle

  • Medial: Lesser tubercle

Attachments

  • Medial attachment: Lesser tubercle of the humerus

  • Lateral attachment: Greater tubercle of the humerus

  • Functional continuity: Coracohumeral ligament and subscapularis tendon fibers

Function

  • Retains the long head of the biceps tendon within the bicipital groove

  • Stabilizes the anterior aspect of the shoulder

  • Prevents biceps tendon subluxation during rotation and elevation

  • Reinforces the roof of the intertubercular groove

  • Part of the soft-tissue bicipital pulley system

Clinical Significance

  • Integrity of THL is important in biceps tendon stability

  • Injury contributes to biceps subluxation/dislocation

  • May be implicated in rotator interval pathology

  • Frequently evaluated in shoulder instability, overhead athletes, and tendon tears

  • Damage often coexists with subscapularis tendon tears

MRI Appearance

T1-weighted images:

  • THL appears as a thin low-signal band spanning the bicipital groove

  • Long head of biceps tendon: low signal running deep to ligament

  • Surrounding fat: bright, enhancing visibility of ligament borders

T2-weighted images:

  • THL remains low signal, though slightly less conspicuous due to bright joint fluid or edema

  • Distinct smooth contour forming the roof of the bicipital groove

  • Biceps tendon: low signal within the tunnel

STIR:

  • Ligament shows as a thin low-signal band

  • Fat suppression increases contrast between ligament and adjacent suppressed fat

  • Smooth, thin hypointense line overlying biceps tendon

Proton Density Fat-Saturated (PD FS):

  • THL appears as a thin, dark, sharply defined band

  • Biceps tendon also low signal but thicker; ligament distinguished by location over the groove

  • Excellent for evaluating ligament continuity and bicipital groove integrity

CT Appearance

Non-Contrast CT:

  • Ligament itself not directly visualized due to soft-tissue density

  • Bicipital groove and tubercles clearly seen as osseous landmarks

  • The groove’s morphology may indirectly suggest pulley function

MRI image

Transverse humeral ligament MRI 3T axial image