Olecranon Process

olecranon

The olecranon is the large posterior prominence of the proximal ulna, providing the insertion for the triceps tendon on its posterior surface and the articular surface of the trochlear notch on its anterior surface. It forms the posterior fulcrum of the elbow hinge, and its tip projects into the olecranon fossa of the humerus during full extension, creating the bony block to hyperextension. The subcutaneous olecranon bursa overlies its posterior surface.

Region: Forearm

Clinical Relevance

Clinical Notes

Olecranon bursitis produces a fluctuant swelling directly over the posterior elbow, caused by direct trauma (single blow or chronic pressure — student's elbow, miner's elbow), crystal deposition (gout, pseudogout), or septic bursitis. Olecranon stress fractures occur in throwing athletes from repetitive triceps traction. Olecranon fractures from direct impact or triceps traction avulsion are treated by tension band wiring (transverse fractures) or plate fixation (comminuted fractures). The olecranon fossa impingement from osteophytes in valgus extension overload is the classic pitcher's elbow complication.

Pathology

Common Injuries & Conditions

Olecranon Stress Fracture in Throwing Athletes

Repetitive triceps traction during the acceleration phase of throwing produces a stress fracture of the olecranon at the anterior cortex of the midolecranon, presenting with posterior elbow pain on release; MRI demonstrates the stress fracture line and bone marrow oedema; throwing rest and gradual return is the standard management, with internal fixation for displaced or non-healing fractures.