Distal Triceps Olecranon Insertion

insertio tendinis tricipitis ad olecranon

The distal triceps tendon inserts on the olecranon via a broad V-shaped footprint: the central fibres (from the long head) insert on the central olecranon tip, the medial fibres expand into the medial deep fascial expansion of the forearm, and the lateral fibres form a lateral fascial expansion. The total footprint spans 3-4 cm on the olecranon with its peak loading in the posterior-superior cortex adjacent to the articular surface.

Region: Forearm

Clinical Relevance

Clinical Notes

Distal triceps avulsion is the rarest tendon rupture of the upper extremity, typically from sudden elbow flexion against a contracting triceps (fall on outstretched hand with direct elbow impact). The Thompson test (squeeze the triceps mass in prone) assesses tendon continuity. Partial tears are treated conservatively; complete avulsions require surgical repair with suture anchors or transosseous bone tunnels through the olecranon footprint. The medial and lateral fascial expansions may partially maintain elbow extension even with complete central tendon avulsion, masking the diagnosis.

Pathology

Common Injuries & Conditions

Distal Triceps Avulsion from Olecranon Footprint

Forced elbow flexion against a maximally contracting triceps avulses the tendon from the olecranon footprint, producing posterior elbow pain, a palpable gap proximal to the olecranon, and weakness of elbow extension; ultrasound or MRI confirms the avulsion and surgical reattachment through transosseous tunnels or suture anchors restores extension strength.