Metacarpals. The metacarpals are long bones within the hand that are connected to the carpals, or wrist bones, and to the phalanges, or finger bones. The metacarpals together are referred to as the metacarpus ..The tops of the metacarpals form the knuckles where they join to the wrist.etacarpals. The metacarpals are long bones within the hand that are connected to the carpals, or wrist bones, and to the phalanges, or finger bones. The metacarpals together are referred to as the metacarpus ..