The pollex is the fixed “finger” of the claw (the movable finger is the dactyl). It is part of the manus; generally there is no specific point which delineates the pollex from the “palm” of the claw.
The pollex of the major cheliped, from the exterior view of the claw (strictly speaking, the posterior surface of the claw if the limbs are spread). Figure modified from Crane (1975).
