Musculoskeletal Sonography for Evaluation of Anatomic Variations of Extensor Tendon Synovial Sheaths in the Wrist

Objectives: The purpose of this article is to show the anatomic variations of extensor tendon synovial sheaths in the wrist. Methods: Videos from 157 patients that were available in the electronic database were reviewed. Sonography showed involvement of 186 tendon sheaths. Results: We describe our center's experience with most tendon variants described in the literature and show the sonographic appearance of the most frequent ones. Conclusions: Sonography is an accepted, safe, and efficient method for evaluating conditions characterized by effusion into the synovial sheaths of the wrist extensor tendons. Knowledge of anatomy and anatomic abnormalities of these sheaths is essential for diagnosis and for correct ultrasound-guided injection therapy or, less frequently, planning a surgical approach.