Figure 5

Distribution of the local thickness of the trapeziometacarpal joint capsule. (a) appearance of the trapeziometacarpal (TMC) joint capsule from the palmar aspect to the dorsal aspect (right thumb). The white star indicates attachment on the dorsoradial edge of the first metacarpal bones. The triangle indicates attachment of the APL supernumerary tendon. The rhomboid indicates the part corresponding with the radial roof of the flexor carpi radialis tendon groove (Dagger in Fig. 1c,d). The dotted line demonstrates the proximal edge of the attachment on the first metacarpal bone. The solid line indicates the borderline between the radial and dorsal aspects of the joint. (b) distribution of the local thickness of the joint capsule. The symbols are the same as in (a). Boxed regions R and D correspond to the radial and dorsal aspects of the TMC joint, respectively. The approximate thicknesses (mm) are shown by different colors in the color bar. c: scatter diagram showing the thicknesses of the R and D regions as shown in (b). The thicknesses are presented as means and standard deviations. Region D (red asterisk) is thicker than region R (paired t-test, P = 0.0000176). Dist, distal; Dors, dorsal.