Figure 3-20.—Forearm and hand. site of fractures; the shaft, which is the main part of the humerus; and the distal end, which includes the prominences called epicondyles and the surfaces that articulate with the bones of the forearm.
When the arm is in the anatomical position with the palm turned forward, the RADIUS is on the lateral, or thumb, side and the ULNA is on the medial, or little finger, side of the forearm. When the hand is pronated (palm turned downward), the bones rotate on each other and cross in the middle. This makes it possible to turn the wrist and hand as in opening doors. The ulna and the radius articulate at their proximal ends with the humerus, at their distal ends with some of the carpal bones, and with each other at both ends.
There are eight CARPAL bones, arranged in two rows, forming the wrist.
The METACARPAL bones are numbered one to five corresponding with the five fingers, or digits, with which they articulate. The fingers are named as follows: 1st thumb; 2nd index; 3rd middle; 4th ring; and 5th little.
The small bones of the fingers are called PHALANGES, and each one of these bones is called a PHALANX. Each finger has three phalanges, except the thumb which has two. The phalanges are named for their anatomical position proximal phalanx is the bone closest to the hand; the distal phalanx is the bone at the end of the finger; and the middle phalanx, the bone located between the proximal and distal phalanges.
LOWER EXTREMITY.— The lower extremity includes the bones of the hip, thigh, leg, ankle,