Section I. UPPER EXTREMITY
The skeleton of the hand (figure 2-1) is divided into three-parts: the carpus, the
metacarpus, and the phalanges digits.
a. The carpus, or wrist, consists of eight carpal bones arranged in two rows.
Those in the proximal row from the lateral to the medial side of the hand are the
navicular or scaphoid, lunate, triangular or triquetrum, and pisiform.
b. The carpals in the distal row are, from lateral to medial, the greater
multangular or trapezium, the lesser multangular or trapezoid, capitate, and hamate.
c. The metacarpus is the bony structure of the hand. It consists of five
cylindrical bones (metacarpals) that articulate proximally with the distal carpals and
distally with the proximal phalanges. The metacarpals are numbered from one to five,
from the thumb to the little finger.
d. The phalanges are the bones of the thumb and fingers. Each hand has 14
phalanges, three in each finger and two in the thumb. In the fingers, the proximal
phalanges articulate proximally with the metacarpals and distally with the middle row of
phalanges. The middle row articulates proximally with the proximal phalanges and
distally with the distal phalanges. The distal end of each distal phalanx is flattened and
expanded to present the ungual tuberosity for the support of the fingernail. In the
thumb, the proximal phalanx articulates proximally with the first metacarpal and distally
with the distal phalanx. Bennett's fracture is a longitudinal fracture of the first
metacarpal bone running into the carpometacarpal joint, complicated by subluxation
(stave of the thumb).
The bones of the forearm (figure 2-2) are the ulna and radius. Both are long
bones that articulate with each other at their proximal and distal ends.