Tenosynovitis of extensor carpi ulnaris.

Axial images at level of distal ulna ( listers tubercle level of radius) shows fluid surrounding the ECU tendon with well defined intrasubstance tendinous splitting suggesting longitudinal tear in concert with mild tenosynovitis at the ulnar styloid fibro-osseous canal. The ECU subsheath is diffusely edematous , mildy fragmented, showing similar but milder involvement of the extensor retinaculum with interposed freefluid.

Coronal images of wrist reveal ulnar sided soft tissue edema and peritendinous free fluid and fibrillary pattern at the sixth extensor compartment which hosts the extensor carpi ulnaris tendon

Complete short segment longitudinal tear of the distal (extensor carpi ulnaris) ECU tendon , which appears undisplaced in the ulnar bony groove under the overlying extensor retinaculum. The tendon sheath and subsheath appear fragmented and edematous with fluid surrounding the tendon . There is evidence of soft tissue edema at ulnar side of wrist with minimal edema at outer fibres of ulnomeniscal homologue. No obvious subluxation of tendon within its sheath or in relation to the ulnar bony groove.

These constellation of findings are consistent with longitudinal tear of ECU with chronic tendinosis in concert with mild tenosynovitis



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