The bones of the upper limb can be divided into four distinct groups: the shoulder girdle, arm, forearm and hand. Unlike the bones of the lower limb, which are primarily involved in weight-bearing and locomotion, the bones of the upper limb are mainly responsible for controlling the hand’s position in space, allowing manipulation of objects in the environment.
The most proximal group of bones, closest to the body, is the shoulder girdle. This consists of two bones – the clavicle and the scapula. The scapula is a flat, triangular bone, which serves as an attachment site for many muscles. The anterior end of the clavicle articulates with the sternum, connecting the upper limb to the axial skeleton – the vertebral column, ribs, and sternum.
The next set of bones in the upper limb is the arm, primarily consisting of the humerus. This bone connects to the scapula at the glenohumeral joint at the proximal end, and the bones of the forearm at the elbow joint at the distal end.
The forearm consists of the ulna and radius, which are articulated medially and laterally, respectively. The ulna provides stability to the forearm, whereas the radius can pivot around it to facilitate movement of the proximal and distal radio-ulnar joints.
The final two groups of bones are located in the hand. The carpals are eight bones, organized into two rows in the wrist area. They articulate distally with five metacarpal bones – one for each digit. Farther down the digits are the phalanges, which are the bones at the tips of the fingers. Each finger has three phalanges, except for the thumb, which has two.
The bones of the upper limb serve a wide variety of functions, from providing stability to creating movement. Knowing their location and function is key for understanding the anatomy of this part of the body.
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