Relation of wrist angles to median nerve conduction studies.
OBJECTIVE
To measure the changes in median nerve conduction parameters at various angles of wrist flexion and extension.


METHODS
We studied 8 patients with carpal tunnel syndrome (CTS) and 4 subjects (5 hands) without the condition (controls). Conduction parameters were measured with the wrist in neutral position and at different wrist angles.


RESULTS
Onset motor latency increased in both groups with wrist extension and decreased with wrist flexion. Sensory onset latency decreased in both groups with wrist flexion. Compound Muscle Action Potential (CMAP) amplitude increased with wrist flexion for both groups. Wrist extension resulted in reduction of the CMAP amplitude in controls; however, for the CTS group it increased for the first 30 degrees and then decreased. Sensory Nerve Action Potential (SNAP) amplitude increased with wrist flexion and decreased with wrist extension in both groups.


CONCLUSIONS
Median nerve conduction parameters improve with wrist flexion and generally worsen with extension.
Cuevas-Trisan
Ramon L
RL
Physical Medicine & Rehabilitation Service, Veterans Affairs Medical and Regional Office Center Program, San Juan, Puerto Rico. ramon.cuevas-trisan@med.va.gov
Ojeda-Rodriguez
Aileen G
AG
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D002349:Carpal Tunnel Syndrome / Q000503:physiopathology* / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D008875:Middle Aged; D009431:Neural Conduction; D009989:Orthotic Devices; D014953:Wrist / Q000502:physiology