The right wrist of twenty cadavers were examined to measure the three dimensions of the carpal tunnel by using a Vernia (INOX), the cross sectional area and volume were then calculated for males and females separately. All were above 40 years. Males were found to have larger carpal tunnel than females of the same age group, both in cross sectional area and volume. It was found also that the volume of the tunnel change according to the age. The pattern by which the volume changes is different in males and females. In active age group i.e. fourth to sixth decade, the tunnel volume in females’ collapse but it expand in males, this may explain the high incidence of carpal tunnel syndrome in females in this age group and the low number of affected males. The age / volume relation may shed some light on the etiology of the “Idiopathic” carpal tunnel syndrome