Phalanges of the hand
|Phalanges of the hand|
|Plan of ossification of the hand.|
|Bones of the left hand. Dorsal surface.|
|Latin||Ossa digitorum manus,
phalanges digitorum manus
|Gray's||subject #56 230|
Each consists of a body and two extremities.
- The body tapers from above downward, is convex posteriorly, concave in front from above downward, flat from side to side; its sides are marked by rough areas which give attachment to the fibrous sheaths of the flexor tendons.
- The proximal extremities of the bones of the first row present oval, concave articular surfaces, broader from side to side than from front to back. The proximal extremity of each of the bones of the second and third rows presents a double concavity separated by a median ridge.
- The distal extremities are smaller than the proximal, and each ends in two condyles (knuckles) separated by a shallow groove; the articular surface extends farther on the palmar than on the dorsal surface, a condition best marked in the bones of the first row.
The ungual phalanges, those most distal, are convex on their dorsal and flat on their volar surfaces; they are recognized by their small size, and by a roughened, elevated surface of a horseshoe form on the volar surface of the distal extremity of each which serves to support the sensitive pulp of the finger.
All of the five proximal phalanges articulate with a corresponding metacarpal bone in the hand through a metacarpophalangeal joint. The proximal, intermediate and distal phalanges articulates with one an other through interphalangeal articulations, proximal and distal interphalangeal joints respectively for the four fingers, while the thumb only contains one interphalangeal joint.
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