An abnormal palmaris longus muscle in the carpal tunnel responsible for carpal tunnel syndrome: a case report

A case of a patient with symptoms and signs of (CTS) is presented. Preoperative ultrasonography (USG) revealed an abnormal palmaris longus muscle in the carpal tunnel, which was probably responsible for the development of the syndrome. The median nerve was hypoechogenic, severely enlarged with blurred echo structure at the level of compression. The patient underwent surgery with the release of the flexor retinaculum and additional release of the antebrachial fascia along the abnormal muscle. The postoperative course was uneventful and the patient made a full recovery. Follow-up ultrasound at 4 months showed normalization of the ultrasound appearance of the median nerve. The importance of preoperative USG in the diagnosis of CTS is emphasized.