The two major arteries of the neck that supply blood to the head and neck are the subclavian artery and the carotid artery. Both give off numerous branches to supply the head and neck organs and the surrounding muscles. They are always arranged in pairs: There is one artery for the right side of the body (Arteria subclavia dextra or Arteria carotis communis dextra) and one for the left side (Arteria subclavia sinistra or Arteria carotis communis sinistra).
Common carotid artery
The common carotid artery originates on the right half of the body at the level of the joint between the sternum and clavicle (sternoclavicular joint) from a common vascular trunk (truncus brachiocephalicus) from the aorta, together with the subclavian artery. On the left side of the body, however, the common carotid artery and the subclavian artery originate directly from the arch of the aorta. The arteria carotis communis runs together with the vena jugularis interna and the nervus vagus in the vascular-nerve-road of the neck under the musculus sternocleidomastoidus and next to the trachea and the oesophagus towards the head.
In the course of the disease, the common carotid artery divides into the external and internal carotid arteries on both sides of the body approximately at the level of the fourth cervical vertebra. This branching is also known as bifurcatio carotidis. Both arteries are surrounded by a membrane of connective tissue (vagina carotica).
Normally, the arteria carotis communis does not release any branches before the division. The glomus organ is located in the area of the bifurcatio carotidis. The cells of the glomus organ react with increased respiration when the pH value or the oxygen partial pressure of the blood drops or the partial pressure of carbon dioxide increases.
Internal carotid artery
The initial part of the internal carotid artery is widened and contains pressure receptors (baroreceptors) that continuously measure blood pressure and also detect changes in blood pressure. The internal carotid artery does not give off any branches in the cervical region and moves towards the head behind the external carotid artery. It enters the skull at the base of the skull.
The artery and its branches supply, among other things, the eye socket, the brain and the frontal sinus. In the area of the skull there are important connections between the internal and external carotid arteries and the subclavian artery. These by-passes are particularly important when the internal carotid artery slowly closes (e.g. in arteriosclerosis).
The supply of blood to the brain can then still be maintained via the slowly expanding connections. However, a sudden narrowing cannot be compensated for by the collaterals! There are several important collaterals: On the one hand, the ophthalmic collaterals are the ophthalmic collaterals to the external carotid artery, with a connection via the facial artery (branch of the external carotid artery) and the ophthalmic artery (branch of the internal carotid artery). The anastomosis to the arteria carotis externa and the arteria subclavia via meningeal arteries are also important. In this way there is a connection between the arteria occipitalis as branch of the carotid artery, the vertebral artery as branch of the arteria subclavia and meningeal vessels of the arteria carotis interna.