Examination of the cross-sectional area of the carpal tunnel on fetal cadavers

This study aimed to determine the anatomical features of the carpal tunnel (CT) in fetal cadavers and understand the role of etiology in the development of carpal tunnel syndrome (CTS). Seventy hand-wrist regions (35 right, 35 left) of 35 fetal cadavers (24 females; 11 males) that were not exposed to environmental factors and handedness were examined. The contents and cross-sectional area (CSA) of the CT were measured using ImageJ ©. The CSA consisting of the flexor tendons and median nerve (MN) in the CT were calculated as a percentage. The results showed that the area covered by the MN and flexor tendons in the CT was significantly smaller in female fetuses (P<0.05). There was no significant difference in other ratios between male and female fetuses (P>0.05). There was no significant difference in the ratios regarding the CT and contents between the right and left-hand sides (P>0.05). It was concluded that the difference in CT anatomy may help explain the variations in the prevalence of CTS among genders. The lack of a difference between the right- and left-hand sides supports the theory that repetitive hand activities, hand dominance, and functional factors play a key role in the development of CTS by causing morphological changes in the CT, MN, and flexor tendons. In our opinion, the examination of CTs that have not been exposed to any environmental effects may provide guidance in understanding the effect of anatomical and morphometric features on the etiology of CTS.