Upper Extremities


The upper extremity consists of three parts: the arm, the forearm, and the hand.

The arm is technically only the region between the shoulder and elbow. It consists of a single long bone called the humerus. The humerus is the longest bone in the upper extremity. The top is large, smooth, and rounded and fits into the scapula in the shoulder. The bottom of the humerus connects to the ulna and radius of the forearm. The radius is connected on the side away from the body (lateral side) and the ulna is connected on the side towards the body (medial side). The humerus and the ulna make up the elbow.

The forearm is the region between the elbow and the wrist. It is formed by the radius on the lateral side and the ulna on the medial side. The ulna is longer than the radius and connected more firmly to the humerus. The radius, however, contributes more to the movement of the wrist and hand than the ulna.

The hand consists of three parts (the wrist, palm, and five fingers) and 27 bones.

The wrist consists of 8 small bones called the carpal bones that are bound by ligaments. These bones are arranged in two rows of four bones each.

The palm consists of five metacarpal bones, one aligned with each of the fingers. The bases of the metacarpal bones are connected to the wrist bones and the heads are connected to the bones of the fingers. The heads of the metacarpals form the knuckles.

The fingers are made up of 14 bones called phalanges. A single finger bone is called a phalanx. Each finger has a proximal phalanx, a middle phalanx, and a distal phalanx, except the thumb which does not have a middle phalanx.

Bird and Cronin offers a wide selection of products for the upper extremities when injuries occur that we feel will help you recover. Arm slings, clavicle braces, shoulder immobilizers, wrist and thumb supports and braces, elbow supports and protectors.