[Joint surfaces of the carpometacarpal articulation of the thumb in man]

With respect of height and width of the proximal joint surface of the macerated 1st metacarpal bone as well as of height of the left trapezium results significant minor values compared with bones of right extremities. The measurement datas of height and width of both joint surfaces at the left macerated specimens are less significant than at left humid preparations. With respect of height of the proximal articular surfaces of the right 1st metacarpal bone, there are greater values than at the cartilageneous preparations by statistical significance. At macerated and humid preparated articulation surfaces of the saddle moint of the thumb there are 3 typical profiles in the 2 main planes: a spiral curve (vaulted in the dorsal or ulnar direction), a circular curve, and a s-shaped curve. The radius of the curve will be determined with adaptation of defined curve patterns. At the distal joint surface of the macerated trapezium, the circularly and spirally curved profiles are significantly much more crooked in the dorso-palmar direction than at the cartilageneous articulation surface on the contrary. The humid preparated distal joint surface of the trapezium in the radio-ulnar direction is clearly much more curved. The spiral form is found in 52,6% of all macerated and in 41,6% of all humid preparated specimens. The s-shaped profile is very rarely found at macerated joints (8%), whereas it appears in 26% at humid preparated surfaces. Corresponding cartilageneous saddle joints of the thumb are even similarly curved in 47% of the radio-ulnar and 40,5% of the dorso-palmar joints slices. The clear majority of the opposite carpometacarpal joint surfaces of the thumb show an individually variabel, partly an incongruent curving attitude. If different profiles at corresponding humid preparated joint surfaces assemble the following curvatures prevail: a) In the radio-ulnar cutting direction the combination: circular curve of the distal joint surface of the trapezium and spiral curve of the proximal surface of the 1st metacarpal bone, b) in the dorso-palmar direction: the combination spiral curve of the distal surface of the trapezium and circular curve of the 1st metacarpal bone.