The radial artery is one of the two main arteries of the forearm, branching from the larger brachial artery near the elbow. This vessel travels down the thumb-side of the forearm, running parallel to the radius bone. Its primary biological function is to deliver oxygenated blood to the muscles of the forearm and ultimately to the hand. It forms a network with the ulnar artery to ensure continuous blood flow in the upper limb.
Surface Anatomy and Palpation
The radial artery is remarkably superficial at the wrist, the location most commonly associated with it. At this distal point, the artery passes immediately over the end of the radius bone, covered only by skin and a thin layer of fascia. This minimal tissue covering is why the radial artery is the preferred site for taking a pulse.
Studies indicate that the average depth of the radial artery from the surface of the skin in adults is approximately 2.5 mm. This shallow position allows clinicians to easily press the artery against the underlying bone to feel the pulsation. To check the pulse, one places two or three fingers on the wrist, positioning them just lateral to the prominent tendon felt on the palm side.
The artery’s superficial course makes it easily accessible without the need for significant pressure. Its predictable location makes it a common access point for various medical procedures beyond simple pulse checks.
Path and Depth Variation
The depth of the radial artery is not consistent along its entire length, but changes significantly as it descends from the elbow to the hand. Near its origin in the upper forearm, the artery runs much deeper, initially protected by the overlapping muscle belly of the brachioradialis muscle. It is situated on the deeper muscles that line the bone.
As the artery moves toward the wrist, its depth gradually decreases, becoming more superficial in the lower third of the forearm. Once it reaches the wrist, it passes over the bone before leaving the anterior compartment of the forearm. It then winds around the side of the wrist, passing beneath certain tendons to reach the back of the hand, where it crosses the anatomical snuffbox.
The artery’s final destination is deep within the palm, where it contributes to the formation of the deep palmar arch. This final segment is securely protected by the muscles and tendons of the hand, contrasting sharply with its exposed position at the wrist.
Key Anatomical Neighbors
At the wrist, the radial artery lies directly on the anterior surface of the distal end of the radius bone. The radius provides the firm, unmoving surface that makes successful pulse palpation possible.
The artery runs in a narrow groove situated between two prominent tendons. Medially, toward the center of the forearm, is the tendon of the flexor carpi radialis muscle. Laterally, toward the outside edge of the forearm, is the tendon of the brachioradialis muscle.
This placement between two tendons helps keep the artery in a consistent and predictable location. The superficial branch of the radial nerve, which provides sensation to parts of the hand, also runs in close proximity to the artery in the lower forearm.