Anatomical Differences in the Shape of the Male and Female Carpal Tunnel

Objective: The purpose of this study was to examine the relationship between the dimensions of the carpal tunnel and sex. Study Design: Basic science. Background: Women have a higher incidence of carpal tunnel syndrome than men, and understanding anatomic factors that may predispose women to developing carpal tunnel syndrome may be informative clinically. Using ultrasound, others have shown that a “squarer” carpal tunnel is associated with carpal tunnel syndrome. Methods and Measures: In this study, we measured cross-sectional area, width, and depth of the carpal tunnels from 8 female and 9 male cadavers in transverse sections made through the carpal tunnel. Results: No significant differences were found between the age, weight, body mass index, or radius-derived stature of the female and male cadavers. The cross-sectional area of the female carpal tunnels (1.34 ± 0.16 cm2) was significantly less (P \u3c 0.01) than the area of the male carpal tunnels (1.66 ± 0.21 cm2). The depth of the carpal tunnel was not significantly different between the sexes, but the average width of the female carpal tunnel (2.04 ± 0.14 cm) was significantly shorter (P \u3c 0.01) than the average width of the male carpal tunnel (2.33 ± 0.15 cm). Conclusions: The depth-to-width ratio of the carpal tunnel was significantly greater (P \u3c 0.05) in the females (0.50 ± 0.07) than in the males (0.43 ± 0.07). Thus, the “squarer” carpal tunnels of females may contribute to the higher incidence of carpal tunnel syndrome in women