Biceps Distal Tendon (Full)

tendo musculi bicipitis brachii distalis

The distal biceps tendon inserts on the posterior radial tuberosity — the tendon must rotate 90 degrees relative to its proximal orientation as the forearm supinates and pronates. Complete distal biceps tendon rupture produces the Popeye sign and 40-50% loss of supination strength with lesser elbow flexion loss. Surgical repair through a two-incision (Boyd-Anderson) or single-incision anterior approach restores full supination strength.

Region: Upper Arm

Biomechanics

Function & Actions

Forearm supination (primary — the most powerful supinator) and elbow flexion through the radial tuberosity lever arm

Clinical Relevance

Clinical Notes

Distal biceps tendon rupture from resisted forearm supination (classically lifting a heavy box) produces an audible pop, antecubital bruising, and the Popeye sign (muscle belly bunching proximally). The hook test (inability to hook the biceps tendon with a finger in the antecubital fossa) confirms complete rupture. Surgical repair within 2 weeks achieves full function; repair is recommended for all active patients.

Pathology

Common Injuries & Conditions

Distal Biceps Tendon Rupture

Complete distal biceps avulsion from the radial tuberosity producing 40-50% supination loss managed with surgical repair within 2 weeks through the anterior single-incision or two-incision approach.