Table III:

Proposed category of mechanisms of CMC injury

Type	Direction of dislocation	Involved Metacarpals	Peculiarity	Possible Mechanisms of Injury
A	Dorsal	1 or more	All in same direction	A direct force applied on the palmer aspect of the metacarpal bases will cause dorsal dislocation which is in the direction of the force
B	Volar	1 or more	All in same direction	A direct force applied on the dorsal aspect of the metacarpal bases will push the metacarpals to the volar side, which is in the direction of the force causing volar dislocation
C	Divergent: Dorsal and Volar	2 or more	At least two in opposite direction	The mechanism here is quite complex involving twisting and rotatory forces. This may cause crushing or supination of the transverse metacarpal arch around an axis passing between third and fourth metacarpals