The internal carotid artery is also known as the internal carotid artery and supplies portions of the brain with arterial blood. Together with the external carotid artery, it arises from the common carotid artery. The internal carotid artery is particularly susceptible to arteriosclerosis as well as smaller aneurysms.
What is the internal carotid artery?
The internal carotid artery is one of the most important arteries in the human body. The pathway of the arterial blood vessel supplies nutrients and oxygen to much of the neck and head. The artery originates on the right side of the brachiocephalic trunk and emerges directly from the aortic arch on the left side. At the so-called carotid bifurcation (bifurcatio carotidis), it divides into internal and external carotid arteries. The former portion corresponds to the internal carotid artery and can be divided into four portions depending on its course and surrounding structures. From caudal to cranial, these portions correspond to the pars cervicalis, petrosa, cavernosa, and cerebralis. Except for the cervical portion, all portions give off multiple branches. In neuroradiology, a cervical segment of the internal carotid artery is distinguished from a petrous, a lacerum, a cavernous, a clinoidal, and an ophthalmic and terminal segment. The external carotid artery is usually weaker than the external carotid artery. Quite a few connections exist between the two arteries.
Anatomy and structure
The branch of the internal carotid artery (carotid sinus) carries pressure receptors. In addition, chemoreceptors located within the glomus caroticum lie at the origin of the artery. In the pars cervicalis, the artery extends from the origin to the base of the skull, which is pierced by the artery through the external opening of the carotid canal (canalis caroticus). In the initial region, the internal carotid artery lies posterior to the external carotid artery and reaches the skull base midway. The pars petrosa runs upward in the temporal bone. At the anterior wall of the tympanic cavity (paries caroticus), the portion makes a midline forward arc toward the sphenoid body. Several branches descend to the tympanic cavity (Arteriae caroticotympanicae) and to the pterygoid canal (Arteria canalis pterygoidea). At the inner opening of the carotid canal, the dura mater encases the internal carotid artery, which rests here on the foramen lacerum. Between the carotid canal wall and the internal carotid artery lies the venous plexus caroticus internus, which connects the cavernous sinus with the pterygoid plexus. On the inner surface of the skull base, the internal carotid artery traverses the cavernous sinus. The pars cavernosa takes an S-shaped arc anteriorly upward. This carotid siphon sends branches to the neurohypophysis (inferior hypophysial artery), the trigeminal ganglion (rami ganglionares trigeminales), the minines (ramus meningeus), and the cavernous sinus (ramus sinus cavernosi). The artery pierces the hard meninges midway from the anterior clinoid process and becomes the pars cerebralis in the subarachnoid space. As it proceeds upward anteriorly, the portion immediately gives rise to the ophthalmic artery, which reaches the eye with the optic nerve and gives rise to the posterior communicating artery. In addition, the internal carotid artery divides into the cerebral arteries anterior and media in this portion.
Function and Tasks
The internal carotid artery supplies oxygenated blood to parts of the brain and eye and also provides nutrients and neurotransmitters to tissues. For example, the cervical portion of the blood vessel corresponds to the neck portion and accordingly supplies the cervical region. The pars petrosa corresponds to the petrous part, which primarily supplies the tympanic cavity. The pars cavernosa, on the other hand, is involved in supplying the trigeminal ganglion, the neurohypophysis, and the hard meninges. The pars cerebralis has some of the most important functions. This portion supplies arterial blood to parts of the brain (anterior choroid artery). In addition, the internal carotid artery is an important artery for cardiovascular regulation. Like all arteries, it carries smooth muscle cells inside. In addition, pressure receptors are located at its outlet, which permanently inform the nervous system about the blood pressure in the arterial system. The autonomic nervous system can carry out counter-regulations on the basis of the information thus received and, if necessary, adjust the heart rate and blood pressure, for example.The cardiovascular center of the brain also processes information from the receptor area of the carotid sinus reflex, which serves to stabilize central blood pressure. The chemoreceptors in the glomus caroticum of the arterial origin additionally transmit the ph value and content of carbon dioxide and oxygen in the blood to the nervous system. The information thus transmitted plays an essential role in the respiratory reflex.
Diseases
The initial segment of the internal carotid artery is particularly susceptible to arteriosclerosis (hardening of the arteries). In the 21st century, arteriosclerotic processes are a widespread disease with extreme prevalence and are now one of the most common causes of stroke and myocardial infarction. The plaques of thrombi, connective tissue, fats and calcium deposited there constrict the vessel lumen and can cause carotid stenosis or trigger an embolism that leads to a cerebral infarction. In addition, hardening of the artery in this area can rupture due to pressure during acute vascular occlusion. Tearing is also often the beginning of arteriosclerotic processes, as the inflammation thus induced can trigger initial proliferation of connective tissue. Within the skull, the internal carotid artery is also predisposed to aneurysms, the rupture of which can cause a highly acute stroke in the sense of a subarachnoid hemorrhage. Apart from this, the venous plexus in the pars petrosa of the internal carotid artery plays a major role in the development of bacterial meningitis.
