The radial artery, together with the ulnar artery, forms the continuation of the brachial artery, which branches into the above two arteries via a bifurcation in the crook of the arm. On its way to the thumb and further fingers, it passes along the radius and forms a series of secondary branches on the forearm, wrist and hand. Above the wrist, the artery is commonly used to measure the pulse.
What is the radial artery?
The radial artery, also called the radial artery, along with the ulnar artery, make up the main forearm arteries, both originating at the bifurcation of the brachial (upper arm) artery in the crook of the arm. While the radial artery travels along the radius of the arm, also called the radius, the ulnar artery travels along the ulna or ulna. Both arteries are the main vessels that supply oxygenated blood to the forearm, wrists and fingers. On its way to the hands, a number of collateral branches arise from the artery to supply the surrounding areas, including muscles. Some of the transverse terminal branches in the hand, the rami perforantes form anastomoses, direct connections with the arteriae metacarpales palmares bypassing the capillary systems. These are further collateral branches of the arterial branches also branching from the radial artery.
Anatomy and structure
The brachial or brachial artery divides in the crook of the arm into the two main branches of the radial and ulnar arteries. The radial artery and its branches in the forearm, wrist, carpus, and branches supplying the parts of the fingers, as well as all other branches, are anatomically classified as muscular arteries, although the cardiac elastic arteries are not always easily distinguished from the muscular type arteries. Whereas the large elastic arteries are mainly involved in the passive Windkessel function and therefore consist mainly of elastic fibers in their middle wall, the media, the subordinate arteries are characterized by smooth muscle cells surrounding the media in an annular or oblique, helical fashion. The smooth muscle cells can react to certain messenger substances and stress hormones with contractions, so that the lumen of the arteries can be changed within certain limits, which has a direct influence on blood pressure. Likewise, elastic fibers present in the tunica media indicate that the arteries are mixed types, or transitional forms with emphasis on muscular.
Function and Tasks
The main function and role of the radial artery is to supply oxygenated blood to certain tissues and muscles in the forearm, wrist, and hand. The oxygen-rich blood is not brought into the capillary plexus from the artery itself, but through smaller arteries that branch off from it. The oxygenated blood originates from the pulmonary circulation and enters the aorta via the left atrium and left ventricle during the systolic tense and ejection phases, from which the brachial artery branches off, which in turn splits into the radial artery and the ulnar artery. In addition to supplying the downstream vessels with oxygenated blood, the radial artery has another function. It is involved in the active regulation of blood pressure. The smooth muscle cells in the middle arterial wall react to stress hormones and to messenger substances, via which vasoconstriction (vasoconstriction) and vasodilation (vasodilation) take place. In acute stress situations and in the case of high physical performance requirements, the peripheral vessels are constricted via the sympathetic nervous system in a vegetative way, and a cascade of further physical reactions runs unconsciously. If the demand and stress phase subsides, the reverse process occurs via parasympathetic nerves, which re-capture or inactivate the stress hormones. The radial artery contributes to the active regulation of blood pressure because the artery is predominantly of the muscular type and responds to the messenger substances of the sympathetic nervous system in the same way as the other arteries, whose central walls are populated with smooth muscle cells. In vascular surgery, a segment of the radial artery is often used as an endogenous substitute or bypass for a diseased coronary artery.
Diseases
There is no known specific disease that predominantly affects the radial artery.However, the ulnar artery, like other arteries of the muscular type, can be affected by dysfunction and disease. The most common problems are caused by narrowing (stenosis) of the artery, which leads to reduced blood transport, so that the resulting complaints are usually sequelae of inadequate supply to certain tissue sections. Stenoses can be caused by inflammatory processes or by arteriosclerosis, which leads to deposits of plaques in the walls of the arteries and which not only sclerotize the arterial walls and make them inelastic, but also gradually obstruct the blood flow because the plaques take up more and more space and a total occlusion, a thrombosis, can develop. Stenosis-like symptoms can also form due to infectious inflammation in the artery. Platelets tend to clump together. It is also possible for thrombi to form elsewhere in the body and be carried around the body via the vascular system. In very rare cases, a migrating thrombus can become lodged and trapped in the radial artery, causing a dangerous embolism. In extremely rare cases, aneurysms, bulges in the radial artery, have also been observed. Such aneurysms can become dangerous if there is a spontaneous rupture in the arterial wall, resulting in appropriate bleeding out or in.
