Anatomy Physiology

In technical anatomical terms, what is commonly known as the arm is really the “upper limb”. Of course, everyone is intimately aware of their arms. We use them before we are even aware of what they are. Arms, and the hand at the end, are a large part of what makes humans unique in the animal word. This article will take a look at the structure and route of the arteries of the upper limb. The arm has a complex blood supply. This blood is vital to the proper functioning of the muscles and bones of the upper limb, or arm.

All blood starts its route around the body in the heart. The left ventricle of the heart pumps blood in to the largest of the arteries, the aorta. From there, the aorta begins to branch off in to smaller arteries, allowing for the proper distribution of blood everywhere in the body.

Early in the aorta are two branches called the subclavian arteries. There is a right and left subclavian artery, with each one being on the right and left side of the body. No surprise there, right. The subclavian arteries are not in the arm itself, rather they are in the chest. But these are the arteries which supply the arm.

The subclavian arteries travel through the shoulder (under the clavicle – hence their name). Once they near the shoulder joint, they become known as the right and left axillary arteries. Of course, all of these arteries are continuous. Anatomists use various landmarks to determine when the subclavian “changes” to the axillary artery.

Once the axillary artery enters the upper arm, it changes names once again to the brachial artery. The bracial artery is the primary artery of the arm. It carries all of the blood supply to the entire arm. From here, as the bachial artery moves down, smaller and smaller branches break off to supply blood to various muscles.

The first major branch of the brachial artery is the profunda brachii. This is a deep artery in the upper arm that is responsible for supplying blood to the triceps and deltoid muscles. It has a couple of named branches as well (the radial and medical collaterals).
The brachial arteries travels down the front of the upper arm between the triceps and biceps muscles. The median nerve, which is one of several important nerves in the arm, follows the course of the brachial artery.

Just below the elbow joint, the brachial artery splits and changes names. The two major branches are the radial and ulnar arteries. Both of these arteries travel the length of the forearm, heading toward the hand. When the brachial artery is in the elbow joint, it is very near the surface – making this the artery that a nurse or doctor is listening to when they take a person’s blood pressure.

Also around the split to the radial and ulnar arteries, the brachial artery gives off several smaller branches, including the radial recurrent, and the anterior and posterior ulnar recurrent. In fact, the anatomy gets quite complicated rather quickly. This article will focus mostly on the larger branches.

The radial and ulnar arteries travel the length of the forearm. The radial artery runs more to the lateral (outside edge) of the forearm, while the ulnar artery is more medial (along the inside edge). They both give off a few smaller branches as they travel down the forearm.
The ulnar and radial arteries end in the wrist, where they actually come back together again, forming two “arches” in the hand. These are known as the deep and superficial palmar arches. In theory, you can loose blood flow through either the radial or ulnar artery, and still get enough blood to the hand.

So there you are – the structure and route of the arteries in the upper limb. If you want to spend a good chunk of your life being tested on the more arcane details of this, nursing or medical school are only an application away!