title: Transverse Movement of the Median Nerve in the Carpal Tunnel during Wrist and Finger Motion in Patients with Carpal Tunnel Syndrome.
abstract: Carpal tunnel syndrome (CTS) is the most common peripheral compression neuropathy of the upper extremity. Repetitive wrist and finger motion has been suggested as a major factor of pathogenesis of CTS. However, little is known about the pathomechanics of CTS. We aimed to evaluate the movement of the median nerve in the carpal tunnel during wrist and finger motions using transverse ultrasound in 21 patients with CTS (5 men and 16 women with mean age 69.0 years). We examined quantitatively the median nerve location as a coordinate within the carpal tunnel at varied wrist positions with all fingers full extension and flexion respectively in the affected and unaffected sides. We thus found that at all wrist positions during finger motion, the median nerve moved significantly more ulnopalmarly in the affected side compared to the unaffected side (p < 0.05). Especially, at the wrist palmar-flexion position as a provocative test, the nerve moved significantly (p < 0.05) the most ulnopalmarly among all wrist positions in the affected side. The nerve was the most strongly compressed against the transverse carpal ligament by the flexor tendons. Additionally, the displacement amount of the nerve in the dorsal-palmar direction was significantly smaller in the affected side than in the unaffected side. These findings indicate that such a pattern of nerve movement has the potential to distinguish affected from unaffected individuals. This ultrasound information could be useful in better understanding of the pathomechanics of CTS, and in further improvement of diagnosis and treatment for CTS.
authors.affiliation: Department of Orthopaedic Surgery, Nippon Medical School.
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Nanno
authors.forename: Takuya
authors.initials: T
authors.lastname: Sawaizumi
authors.forename: Norie
authors.initials: N
authors.lastname: Kodera
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tomori
authors.forename: Shinro
authors.initials: S
authors.lastname: Takai
mesh_terms: D000368:Aged; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D005385:Fingers / Q000502:physiology*; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009068:Movement / Q000502:physiology*; D014463:Ultrasonography; D014953:Wrist / Q000000981:diagnostic imaging / Q000502:physiology*