**21.1 Diagnosis**

The diagnosis of ECU tendon pathology in a golfer requires a high index of suspicion as many patients battle on through the pain thereby worsening the pathology. Excluding the other common injuries can be achieved by a combination of careful history, clinical examination and the use of special tests such as Electrodiagnostic Medicine and radiology.

Dynamic ultrasound is very useful in diagnosing and differentiating the type of tendon pathology. It is the ideal tool to confirm a subduing tendon as it observes the subluxation during ulnar and radial deviation and in flexion and extension motion [38]. The direction of subluxation and the type of sub-sheath injury being confirmed by dynamic imaging. In cases of significant subluxation in professional golfers, surgery is often warranted to repair ECU and its supporting structures.
