In the MCP joints, they also indirectly provide stability to the longitudinal palmar arches of the hand.

[2][3] The volar plate of the thumb MCP joint has a transverse longitudinal rectangular shape, shorter than those in the fingers.

[4] This fibrocartilaginous structure is attached to the volar base of the phalanx distal to the joint.

[6] Due to its fibrocartilaginous composition, the plate is thus able to (1) resist tensile stresses while (2) restricting hyperextension and compression and (3) protecting the volar articular surface.

It forms the bottom of a two-sided box, the sides of which are made up of the collateral ligaments.