Muscle intrusion as a potential cause of carpal tunnel syndrome.
BACKGROUND
The aim of this study was to determine whether there is an association between flexor digitorum and lumbrical muscle intrusion into the carpal tunnel and carpal tunnel syndrome (CTS).


METHODS
Five hundred thirteen manual laborers (1026 wrists) were evaluated with ultrasound to determine whether those with CTS had more muscle intrusion into the carpal tunnel than those without CTS. One hundred ninety of the participants without CTS at baseline (363 wrists) were followed over 1 year to determine whether muscle intrusion at baseline predicted the development of CTS.


RESULTS
Participants with CTS had more muscle within the carpal tunnel with the wrist in the neutral (P=0.026) and flexed (P=0.018) positions than those without CTS. Baseline muscle intrusion did not predict development of CTS at 1 year.


CONCLUSIONS
Muscle intrusion into the carpal tunnel is associated with CTS, but muscle intrusion alone does not predict the development of CTS over the course of a year.
Department of Neurology, Wake Forest School of Medicine, Main Floor Reynolds Tower, Winston-Salem, North Carolina, 27157, USA; Center for Worker Health, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
Michael S
MS
Cartwright
Francis O
FO
Walker
Jill C
JC
Newman
Thomas A
TA
Arcury
Dana C
DC
Mora
Chen
C
Haiying
Sara A
SA
Quandt
D000328:Adult; D002348:Carpal Bones / Q000473:pathology* / Q000648:ultrastructure; D002349:Carpal Tunnel Syndrome / Q000000981:diagnostic imaging / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D056865:Ideal Body Weight; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology* / Q000503:physiopathology*; D014463:Ultrasonography; D014953:Wrist / Q000294:innervation; D055815:Young Adult
carpal tunnel syndrome; electromyography; incidence; prevalence; ultrasound