In human anatomy, the radial artery is the main

artery An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

of the lateral aspect of the

forearm The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in ...

Structure

The radial artery arises from the bifurcation of the brachial artery in the antecubital fossa. It runs distally on the anterior part of the forearm. There, it serves as a landmark for the division between the anterior and posterior compartments of the forearm, with the posterior compartment beginning just lateral to the artery. The artery winds laterally around the

wrist In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carp ...

, passing through the anatomical snuff box and between the heads of the first dorsal interosseous muscle. It passes anteriorly between the heads of the adductor pollicis, and becomes the deep palmar arch, which joins with the deep branch of the

ulnar artery The ulnar artery is the main blood vessel, with oxygenated blood, of the medial aspects of the forearm. It arises from the brachial artery and terminates in the superficial palmar arch, which joins with the superficial branch of the radial ar ...

. Along its course, it is accompanied by a similarly named

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenat ...

, the radial vein.

Branches

The named branches of the radial artery may be divided into three groups, corresponding with the three regions in which the vessel is situated.

In the forearm

Radial recurrent artery The radial recurrent artery arises from the radial artery immediately below the elbow. It ascends between the branches of the radial nerve, lying on the supinator muscle and then between the brachioradialis muscle and the brachialis muscle, supp ...

- arises just after the radial artery comes off the brachial artery. It travels superiorly to anastomose with the radial collateral artery around the elbow joint * Palmar carpal branch of radial artery - a small vessel which arises near the lower border of the pronator quadratus * Superficial palmar branch of the radial artery - arises from the radial artery, just where this vessel is about to wind around the lateral side of the wrist.

At the wrist

* Dorsal carpal branch of radial artery - a small vessel which arises beneath the extensor tendons of the thumb * First dorsal metacarpal artery - arises just before the radial artery passes between the two heads of the first dorsal interosseous muscle and divides almost immediately into two branches which supply the adjacent sides of the thumb and index finger; the lateral side of the thumb receives a branch directly from the radial artery.

In the hand

Princeps pollicis artery The princeps pollicis artery, or principal artery of the thumb, arises from the radial artery just as it turns medially towards the deep part of the hand; it descends between the first dorsal interossei of the hand, dorsal interosseous muscle and ...

- arises from the radial artery just as it turns medially to the deep part of the hand. * Radialis indicis - arises close to the princeps pollicis. The two arteries may arise from a common trunk, the first palmar metacarpal artery. * Deep palmar arch - terminal part of radial artery.

Variations

In less than 1% of the population, the radial artery takes a superficial course in the anatomical snuff box. This arterial variation can be mistaken for the

cephalic vein In human anatomy, the cephalic vein is a superficial vein in the arm. It originates from the radial end of the dorsal venous network of hand, and ascends along the radial (lateral) side of the arm before emptying into the axillary vein. At the e ...

as accidental injection of this variant radial artery has been reported. Identifying arterial pulsation in the anatomical snuff box is therefore recommended.

Clinical significance

The radial artery lies superficially in front of the distal end of the

radius In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...

, between the tendons of the brachioradialis and flexor carpi radialis; it is here that clinician takes the radial pulse. (where it is commonly used to assess the

heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...

and cardiac rhythm). Presence of ''radial pulse'' was thought to indicate a systolic blood pressure of at least 70 mmHg, as estimated from the 50% percentile, although this was found to generally be an overestimation of a patient's true blood pressure. The radial artery can be less easily felt as it crosses the anatomical snuff box. The radial artery is used for

coronary artery bypass graft Coronary artery bypass surgery, also known as coronary artery bypass graft (CABG, pronounced "cabbage") is a surgical procedure to treat coronary artery disease (CAD), the buildup of plaques in the arteries of the heart. It can relieve chest pai ...

ing and is growing in popularity among cardiac surgeons. Recently, it has been shown to have a superior peri-operative and post-operative course when compared to saphenous vein grafts. The radial artery is often punctured in a common procedure to obtain an

arterial blood gas An arterial blood gas (ABG) test, or arterial blood gas analysis (ABGA) measures the amounts of arterial gases, such as oxygen and carbon dioxide. An ABG test requires that a small volume of blood be drawn from the radial artery with a syringe an ...

. Such a procedure may first involve an

Allen's test In medicine, Allen's test or the Allen test is a medical sign used in physical examination of arterial blood flow to the hands. It was named for Edgar Van Nuys Allen, who described the original version of the test in 1942. An altered test, first ...

. The radial artery is also used to evaluate the

collateral circulation Collateral circulation is the alternate circulation around a blocked artery or vein via another path, such as nearby minor vessels. It may occur via preexisting vascular redundancy (analogous to engineered redundancy), as in the circle of Wil ...

of blood through the hands; applying pressure through palpating the palmar arches results in paleness over the area being compressed; adequate collateral circulation can be ascertained by how quickly normal colour returns after the pressure is removed. The radial artery is a common site for the insertion of an

arterial line An arterial line (also art-line or a-line) is a thin catheter inserted into an artery. Use Arterial lines are most commonly used in intensive care medicine and anesthesia to monitor blood pressure directly and in real-time (rather than by int ...

, such as for blood pressure monitoring in an

intensive care unit 220px, Intensive care unit An intensive care unit (ICU), also known as an intensive therapy unit or intensive treatment unit (ITU) or critical care unit (CCU), is a special department of a hospital or health care facility that provides intensi ...

. It is selected because it is accessible, and because of the low incidence of complications such as

thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (t ...

Additional images

File:Gray417 color.PNG, Cross-section through the middle of the forearm. File:Gray527.png, The radial and ulnar arteries. File:Gray1235.png, Front of right upper extremity, showing surface markings for bones, arteries, and nerves. File:Slide9GGG.JPG, Radial artery and vein File:Gray416.png, Radial artery in the

anatomical snuffbox The anatomical snuff box or snuffbox or foveola radialis is a triangular deepening on the Anatomical terms of location#Relative directions, radial, Dorsum (biology), dorsal aspect of the hand—at the level of the carpal bones, specifically, the S ...

References

External links

Image at umich.edu – pulse
– medicalstudents.com * {{Authority control Arteries of the upper limb