The upper limb is articulated to the trunk by means of a ball-and-socket joint between the humerus and scapula. The limb is slung to insure as much mobility as possible, the joint being a very loose one, and the scapula is attached to the trunk by muscles between it and the vertebrae at the back, and to the clavicle in front. The scapulae and clavicles form what is known as the Shoulder Girdle.

The bones to be described in the shoulder girdle and upper limb are the following:

Clavicle, articulated internally to the sternum; externally, to the acromion process of scapula.

Scapula, articulated externally to acromial end of clavicle and to head of humerus.

Humerus, articulated above to glenoid cavity of scapula; below, to heads of ulna and radius.

Ulna, articulated above to internal condyle of humerus and to head of radius; below, to triangular fibro-cartilage of wrist-joint,

Radius, articulated above to external condyle of humerus and to head of ulna; below, to the scaphoid and semilunar bones of the carpus.

Carpus, articulated above to radius; below, to five metatarsals.

Metatarsals, articulated above to bones of carpus; below, to phalanges.

Phalanges : First row-articulated above to metatarsals; below, to second row of phalanges.

Second row - above, to first row of phalanges; below, to third row of phalanges.

Third row - above, to second row of phalanges.