Division of carpal tunnel into quartiles to calculate volume distribution.

Panel A shows points at 0%, 25%, 50%, 75%, and 100% of the distance along the vector between the centroids of the proximal and distal ends of a representative carpal tunnel in neutral posture. Panel B shows the planes which divide the tunnel oriented as a weighted average of the proximal and distal boundary normal vectors. Panel C shows the division of the tunnel volume into quartiles, where Q1(proximal) is red, Q2 is green, Q3 is blue, and Q4 (distal) is black.