Angular Artery: Structure, Function & Diseases

As a branch of the facial artery, the angular artery supplies the ocular ring muscle, lacrimal sac, and orbital and infraorbital regios. Arterial damage, such as that caused by aneurysm and/or embolism, can lead to necrosis of the affected tissue.

What is the angular artery?

The angular artery represents a branch of the facial artery (facial artery or maxillary external artery). The facial artery supplies blood to numerous regions of the head, in which it transports oxygen, among other things. Since the angular artery is part of the systemic circulation, it brings vital respiratory gas from the lungs to the lacrimal sac, the eye ring muscle, and the skin in the orbital and infraorbital regions. Regardless of where they are located: Cells suffering from oxygen and energy deficiency can no longer perform their tasks adequately and die after some time if the deficiency state persists. The affected tissue necrotizes in such a case.

Anatomy and structure

After various branches have branched off from the facial artery, the angular artery remains as the terminal branch of it. It runs from the bottom to the top of the nose and finally leads to the inner corner of the eye. Its course is similar to that of the angular vein. In contrast to the angular vein, the angular artery transports oxygenated blood. The red blood cells (erythrocytes) load themselves with it in the lungs and flow first to the heart. The powerful muscle then pumps the blood into the aorta, from where the blood takes two different routes depending on the side of the body. On the left, the aorta directly feeds the common carotid artery. On the right side of the body, blood flows from the aorta into the brachiocephalic trunk, also known as the innominate artery or the anonyma artery, whose branches on the right side include the common carotid artery. Subsequently, the common carotid artery divides into the internal and external carotid arteries (internal carotid artery and external carotid artery). From the latter branches off the facial artery, which finally merges into the angular artery. Natural connections to other blood vessels exist between the angular artery and the infraorbital artery and the dorsalis nasi artery. Anatomy refers to such connections as anastomoses.

Function and Tasks

The functions of the angular artery include supplying the lacrimal sac. This is located in the inner corner of the eye in the lacrimal sac pit (lacrimal fossa) and is part of the lacrimal apparatus (lacrimal apparatus). Furthermore, the angular artery is responsible for the blood supply of the eye ring muscle (Musculus orbicularis oculi). This lies in the orbit around the visual organ. Contraction of the orbicularis oculi muscle closes the eyelid and participates in the squinting of the eyes. In addition, the orbicularis oculi muscle is able to dilate the lacrimal sac, allowing the lacrimal fluid to drain more easily. It finally enters the nose through the nasolacrimal duct (ductus nasolacrimalis), which is 20 to 25 mm long. The facial nerve is responsible for the neuronal innervation of the orbicularis oculi muscle; its motor fibers control tension and relaxation of the muscle. The angular artery also supplies oxygenated blood to two areas of the skin. The regio orbitalis is located at the eye and also includes the eyelids as well as the eye itself. Below the orbital regio is the infraorbital regio, whose cells also depend on the blood supply from the angular artery.

Diseases

Aneurysm of the angular artery can lead to death of skin cells located in the affected area if the tissue is undersupplied as a result. Aneurysms can manifest not only in arteries, but also in ventricles and veins. The affected blood vessel sags when an aneurysm forms, creating a sac. The dilatation may also take on a spindle shape. In the process, the aneurysm greatly stretches the wall of the affected artery and reduces its flexibility. This can cause the blood vessel to rupture. In addition, blood clots (thrombi) may be deposited in the aneurysm. If they break loose, they can cause an occlusion at narrower points of the artery, which medicine calls an embolism.In addition to thrombi, fat, calcium, undissolved gases and foreign bodies can also cause such occlusion. The skin regions for whose supply the angular artery is responsible may necrotize as a result of damage caused by an aneurysm. At first glance, the clinical appearance resembles damage that can be caused in some cases by the use of so-called dermal fillers in plastic surgery. However, in the course of such cosmetic procedures, in some cases the arteries of the face located in the corresponding region also take damage. Redness, blistering and other skin changes may occur; stabbing pain may indicate an embolism of the artery. During treatment, physicians may need to remove the necrotized areas of skin. Angular artery embolism is also possible if a thrombus forms in another blood vessel and flows to it through the bloodstream. However, vessel occlusions caused by such thrombi affect the angular artery less frequently than arteries flowing to the brain. Because the angular artery anastomoses with the nasal dorsal artery, the effects may also be seen in areas for which the nasal dorsal artery is responsible. This includes the skin of the bridge of the nose as well as the root of the nose.