Longitudinal sliding of the median nerve in patients with carpal tunnel syndrome.

In nerve compression syndromes restricted nerve sliding may lead to increased strain, possibly contributing to symptoms. Ultrasound was used to examine longitudinal median nerve sliding in 17 carpal tunnel syndrome patients and 19 controls during metacarpophalangeal joint movement. Longitudinal movement in the forearm averaged 2.62 mm in controls and was not significantly reduced in carpal tunnel syndrome (CTS) patients (mean=2.20 mm). In contrast, CTS patients had a 40% reduction in transverse nerve movement at the wrist on the most, compared to least, affected side and nerve areas were enlarged by 34%. Normal longitudinal sliding in the patients indicates that nerve strain is not increased and will not contribute to symptoms.