The right subclavian artery arises from the bifurcation of the innominate artery.

The left subclavian, artery arises from the arch of the aorta. In both cases the artery arches outwards across the root of the neck and is the beginning of the main artery of the upper limb.

At the outer border of the first rib it enters the axilla, or armpit, and receives the name of the axillary artery. The axillary artery is the direct continuation of the subclavian. It passes through the axilla to the lower border of the teres major muscle.

The brachial artery is a continuation of the axillary, and reaches to just below the bend of the elbow, where it divides into the ulnar and radiai.

The ulnar artery is the larger of the two. It runs down the inner side of the forearm, and ends in the superficial palmar arch, where it is joined by a branch from the radial.

The radial artery extends along the front of the forearm as far as the end of the radius, where it turns round the outer border of the wrist, and passes between the thumb and the index-finger into the palm of the hand, where it forms the deep palmar arch.

The superficial and deep palmar arches supply the hand with blood.

Numerous branches are sent off from these arteries to supply neighbouring muscles.