Radial Artery

Original Editor - Anthonia Abraham Top Contributors - Anthonia Abraham and Simisola Ajeyalemi

Description

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The Radial artery is a large blood vessel that provides oxygenated blood to the lateral aspect of the forearm, wrist and hand. The radial artery, with the radial vein, runs distally on the anterior part of the forearm, In less than 1% of the population, the radial artery takes a superficial course in the anatomical snuff box.[1] It is recommended for arterial pulsation to taken at the anatomical snuffbox. This is because the variation of the radial artery can be mistaken for the cephalic vein. The brachial artery terminates at the cubital fossa where it bifurcates into the ulnar artery and a smaller radial artery.[2]

Path

The radial artery forms as a bifurcation of the brachial artery in the antecubital fossa. It runs distally, serving as a landmark for the division between the anterior band and posterior compartments of the forearm. The radial and ulnar arteries originate as a bifurcation of the axillary artery in the cubital fossa and serve as the major perforators to the forearm. Following its bifurcation, the radial artery runs along the lateral aspect of the forearm between the brachioradialis and flexor carpi radialis muscles. Immediately proximal to the wrist, it splits into the superficial and deep palmar branches forming an anastomosis with the distal branches of the ulnar artery in the hand. [3]

The posterior compartment begins just lateral to the artery winds laterally around the wrist passes 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.[2]

The radial artery gives off into the forearm, the wrist, and the hand.

At the forearm, the radial artery divided into:

  • Radial recurrent artery; This arises after the radial artery comes off from the radial artery immediately below the elbow. It travels superiorly to anastomose with the radial collateral artery at the elbow joint.
  • Palmer carpal branch of the radial artery; A smaller vessel which arises near the lower border of the pronator quadratus. is and, running across the front of the carpus, anastomoses with the palmar carpal branch of the ulnar artery. A small branch of the radial artery which arises near the lower border of the pronator quadratus, Running forward, it passes through, occasionally over, the thenar muscles, which it supplies, and sometimes anastomoses with the terminal portion of the ulnar artery, completing the superficial palmar arch.

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; is an anatomical term for the combination (anastomosis) of the dorsal carpal branch of the radial artery and the dorsal carpal branch of the ulnar artery near the back of the wrist. It is made up of the dorsal carpal branches of both the ulnar and radial arteries. It also anastomoses with the anterior interosseous artery and the posterior interosseous artery. The arch gives off three dorsal metacarpal arteries[4].
  • First dorsal metacarpal artery

In the hand,

  • Princeps pollicis artery; 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 interosseous muscle and the oblique head of the adductor pollicis, along the medial side of the first metacarpal bone to the base of the proximal phalanx, where it lies beneath the tendon of the flexor pollicis longus muscle and divides into two branches. These make their appearance between the medial and lateral insertions of the adductor pollicis, and run along the sides of the thumb, forming an arch on the palmar surface of the distal phalanx, from which branches are distributed to the integument and subcutaneous tissue of the thumb.
  • Radialis indicis; (radial artery of index finger) is a branch of the radial artery that provides blood to the index finger. It arises close to the princeps pollicis artery, and descends between the first dorsal interosseous muscle and the transverse head of the adductor pollicis, and runs along the lateral side of the index finger to its extremity, where it anastomoses with the proper digital artery, At the lower border of the transverse head of the adductor pollicis, this vessel anastomoses with the princeps pollicis, and gives a communicating branch to the superficial palmar arch. The princeps pollicis and radialis indicis may arise from a common trunk termed the first palmar metacarpal artery.
  • Deep palmer arch; (deep volar arch) is an arterial network found in the palm. It is usually formed mainly from the terminal part of the radial artery, with the ulnar artery contributing via its deep palmar branch, by an anastomosis. This is in contrast to the superficial palmar arch, which is formed predominantly by the ulnar artery. The deep palmar arch lies upon the bases of the metacarpal bones and on the interossei of the hand, is covered by the oblique head of the adductor pollicis muscle, the flexor tendons of the fingers, and the lumbricals of the hand. Alongside of it, but running in the opposite direction—toward the radial side of the hand—is the deep branch of the ulnar nerve. The superficial palmar arch is more distally located than the deep palmar arch. If one were to fully extend the thumb and draw a line from the distal border of the thumb across the palm, this would be the level of the superficial palmar arch (Boeckel's line). The deep palmar arch is about a finger width proximal to this. The connection between the deep and superficial palmar arterial arches is an example of anastomosis, and can be tested for using Allen's test. From the deep palmar arch emerge palmar metacarpal arteries.[4]

Supply

The radial artery provides blood supply to the elbow joint, lateral forearm muscles, radial nerve, carpal bones and joints, thumb, and lateral side of the index finger.

The radial recurrent artery ascending between the branches of the radial nerve, lying on the supinator muscle and then between the brachioradialis muscle and the brachialis muscle, supplies these muscles and the elbow-joint.

Palmer carpal branch of the radial artery supplies the pronator quadratus and the thenar muscles,

Branches of the radial artery also supply muscles of the thumb with the princeps pollicis artery whose branches are distributed to the integument and subcutaneous tissue of the thumb and the radialis indicis supplying the medial side of the finger.[4]

[5]
[6]

Clinical Relevance

The radial artery is clinically significant as a medium to assess the heart rate. Most clinicians take the radial pulse between the tendons of the brachioradialis and flexor carpi radialis. This is because it is where the radial artery lies superficially and thus makes the pulse more detectable.[3]

Allen's test is used to assess the arterial blood supply of the hand. in most scenarios, the radial and ulnar arteries are compressed. The ulnar artery is then released and the pattern of filling in the hand is observed and assessed.[7] Allen’s test plays an important role as a screening method to assess the circulation of the hand before harvesting the radial artery to be used as an arterial conduit for a coronary artery bypass graft. The radial artery is an ideal graft candidate due to its diameter, length, and ease of harvesting of the blood vessel. This test can also be used before sampling blood from the radial artery for arterial blood gas analysis.[2]

References

  1. Wood S J, Abrahams P H,Sañudo J R,Ferreira BJ. Bilateral superficial radial artery at the wrist associated with a radial origin of a unilateral median artery.1996.US National Library of Medicine.National Institutes of Health. Available from:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1167715/ (last accessed 30.12.2020)
  2. 2.0 2.1 2.2 https://www.kenhub.com/en/library/anatomy/radial-artery
  3. 3.0 3.1 Richard M. M; Zachary G.Anatomy, Shoulder and Upper Limb, Forearm Radial Artery. InStatPearls [Internet] August 15, 2020. StatPearls Publishing. Available from:https://www.ncbi.nlm.nih.gov/books/NBK546626/ (last accessed 30.11.2020)
  4. 4.0 4.1 4.2 Henry G, The Radial Artery.The complete 20th U.S. edition of Gray's Anatomy of the Human Body. PHILADELPHIA: LEA & FEBIGER, 1918.  page 594 
  5. Audiopedia. Radial Artery. Available from: https://www.youtube.com/watch?v=y_5G25osdwg&feature=youtu.be [last accessed 30/11/2020]
  6. Dr A K Singh. Radial Artery in forearm and hand. Available from: https://www.youtube.com/watch?v=C-ShgaPs45s&feature=youtu.be [last accessed 30/11/2020]
  7. Allen's test, Clinical examination,https://ecampusontario.pressbooks.pub/clinicalexamination/chapter/allens-test/ (accessed 30 November 2020)