The phalanges in a human hand

The name Phalanges is commonly given to the bones that form fingers and toes. In primates such as humans and monkeys, the thumb and big toe have two phalanges, while the other fingers and toes consist of three.

The phalanges do not really have individual names but are named after the digit, and their distance from the body. Distal phalanges are at the tips of the fingers and toes, the proximal phalanges are closest to the hand (or foot) and articulate with the metacarpals or metatarsals. Middle phalanges are between the distal and proximal. The thumb and big toe do not have middle phalanges.

The phalanges of the foot correspond with those of the hand. They differ from them in their size (the bodies being much reduced in length) and being laterally compressed.

First Row, The body of each is compressed from side to side, convex above, concave below. The base is concave; and the head presents a trochlear surface for articulation with the second phalanx.

Second Row, The phalanges of the second row are remarkably small and short, but rather broader than those of the first row.

The ungual phalanges, in form, resemble those of the fingers; but they are smaller and are flattened from above downward; each presents a broad base for articulation with the corresponding bone of the second row, and an expanded distal extremity for the support of the nail and end of the toe.

The phalanges are each ossified from two centers: one for the body, and one for the base. The center for the body appears about the tenth week, that for the base between the fourth and tenth years; it joins the body about the eighteenth year.