Common Extensor Origin

tendo communis musculorum extensorum

The common extensor origin is the conjoined attachment of the wrist and finger extensors to the lateral epicondyle. The ECRB component — which is deep and anterior, in direct contact with the radiocapitellar joint — is the primary pathological tissue in lateral epicondylalgia (tennis elbow). Its angiofibroblastic degeneration (not inflammation) produces the chronic pain of tennis elbow in 80-90% of lateral epicondyle pain syndromes.

Region: Upper Arm

Biomechanics

Function & Actions

Transmits extensor muscle forces from the lateral epicondyle; the ECRB component is the primary pathological tendon in lateral epicondylalgia

Clinical Relevance

Clinical Notes

Lateral epicondylalgia affects 1-3% of the population and is most common in the dominant arm of 40-50 year olds doing repetitive forearm activities. The Cozen and Mill tests reproduce pain. First-line treatment is load management and eccentric wrist extension exercises. Corticosteroid injection provides short-term relief but worse 1-year outcomes than physiotherapy. PRP injection has the most evidence for biological tendon stimulation. Surgical ECRB debridement for refractory cases resolves 85-90%.

Pathology

Common Injuries & Conditions

Lateral Epicondylalgia (Tennis Elbow)

ECRB angiofibroblastic degeneration at the common extensor origin producing lateral elbow pain managed with eccentric loading, PRP injection, and surgical debridement.