the carotid arteries are major blood vessels in the neck that supply blood to the brain neck and face we have two carotid arteries one on the right side of the body and the other on the left the right common carotid artery arises from a split or bifurcation of the brachiocephalic trunk the right subclavian is the other branch which is a branch of the aortic arch this bifurcation occurs roughly at the level of the right sternoclavicular joint level of t2 vertebrae the left common carotid artery branches directly from the arch of the aorta both the left and right common carotid arteries travel up the neck at roughly the level of the thyroid cartilage and cervical vertebrae 4 or c4 the carotid artery splits into the external and the internal branches this bifurcation happens in an anatomical area called the carotid triangle just above the bifurcation of the common carotid artery there is an area called the crotted sinus in this area the common carotid and internal carotid are slightly dilated this is an important area as it contains baroreceptors which are sensors that help the body detect and regulate blood pressure at the bifurcation of the common carotid artery there is also the carotid body a chemoreceptor important in maintaining oxygen levels in the blood first off let's take a look at the external carotid artery which supplies blood to the areas of the head and neck external to the cranium after arising from the common carotid artery it travels up the neck passes behind the mandibular neck and in front of the lobule of the ear the external carotid artery has a number of branches in ascending order these are superior thyroid artery ascending pharyngeal artery lingual artery facial artery occipital artery posterior auricular artery maxillary archery superficial temporal artery the internal carotid arteries as their name suggests takes a different path carrying blood internally into the cranial cavity they do this via the carotid canal in the petrous part of the temporal bone unlike the external carotid artery the internal carotid artery do not supply any structures in the neck instead they supply the brain by joining and forming the circle of willis the eyes through the ophthalmic artery and the forehead now that we've given an overview of the anatomy of the carotid arteries let's take a look at how these structures are clinically relevant clinical anatomy carotid pulse the carotid arteries are a commonly used site for assessment of a patient's pulse as the heart pushes blood through the arteries the arteries expand and contract with the flow of blood palpation of the cardiac arteries in the neck can be used to assess the pulse rate the the heart rhythm or character and the strength of the pulse the crotted arterial pulses are best examined with the patient supine and the trunk of the patient's body slightly elevated and is measured by placing the fingers behind the larynx and the anterior border of the sternocleidoid mastoid muscle it is very important to not palpate both carotid arteries at the same time as this reduces blood flow to the brain clinical anatomy carotid artery hypersensitivity we previously talked about the carotid baroreceptors which are sensors and regulators of blood pressure baroreceptors are stretch and pressure receptors so you can imagine if external pressure was placed on the carotid sinus the baroreceptors within the crowded sinus would think there is an increase in blood pressure they would then communicate this with your brain to reduce your heart rate in order to reduce and restore blood pressure levels normally this is only a small amount however in some people the carotid sinus over-reacts to the external pressure making their heart slow down or their blood pressure drop a significant amount and this is called carotid sinus hypersensitivity this overreaction can be triggered by wearing tight clothing around the neck or even turning the head the response is manifested clinically as syncopy or pre-syncope and can lead to falls and injury carotid sinus hypersensitivity is only treated if people are symptomatic if the condition causes the patient's heart rate or heart rate and blood pressure to fall substantially they are offered a pacemaker clinical anatomy carotid plaque atherosclerosis and ischemic stroke the next condition we are going to talk about is arthrosclerosis now atherosclerosis is deposition of plaques or fatty material on the inner wall of the arteries when this occurs blood flow is reduced atherosclerosis usually occurs at bifurcations branching regions and regions where there is high curvature of vessels the example in the bifurcation of the common carotid artery for example in the bifurcation of the common carotid artery into the internal and external carotid arteries the internal cardiac artery is the most susceptible to atherosclerosis and can result in reduced blood flow to the brain this can result in pre-syncopy or even syncope concerningly if a piece of the plaque ruptures breaks off and migrates up it can occlude the cerebral arteries causing an ischemic stroke to assess the severity of the vessel wall thickening in the carotid arteries a doppler study can be used to enable estimation of the blood flow through the vessel if the condition is severe if the plaque is severe enough the artery can be surgically cut open and the arthromatous tunica intima that plaque can be removed to restore the blood flow this procedure is referred to as a carotid endarterectomy if this is not possible there is also carotid angioplasty and stenting which can be done clinical anatomy carotid artery aneurysm atherosclerosis is a risk factor for a condition called a carotid artery aneurysm which is a balloon-like bulge or dilation of the carotid artery as the artery expands the wall becomes progressively thinner increasing the chance that the aneurysm will burst any segment of the carotid artery can be affected however the internal carotid artery is the most commonly involved carotid artery aneurysms can be associated with certain diseases including marfan syndrome fibromuscular dysplasia and giant cell arteritis diagnosis of a carotid artery aneurysm may be made incidentally in patients who are asymptomatic or suspected due to the clinical manifestations these clinical manifestations include presence of a pulsatile mass in the neck it can be from a mass effect so the aneurysm may push against nearby nerves for example in the cavernous sinus it can push against nerves here causing ophthalmoplegia it can also push against the vagus nerve causing horse voice it can also push against the internal jugular vein not a nerve and when it pushes against an internal jugular vein it causes compression and facial swelling from backflow finally another clinical manifestation is that the aneurysm can rupture and bleed diagnostic tests include a crowded angiography which will reveal the aneurysm here is an example clinical anatomy carotid artery dissections a young person's stroke this next condition we will be discussing is a carotid artery dissection now this is a serious condition involving injury to the innermost wall of the carotid artery this tear creates two channels of blood flow the first is the normal lumen of the carotid artery and the other is in the wall where blood remains stationary the blood that remains in the wall results in narrowing or stenosis or complete occlusion of the artery resulting in reduction or elimination of the blood flow in the dissection bloods can clot and form and they can also break off from the site of the dissection they can form an emboli these can travel through the arteries of the brain and block blood supply in the brain causing an ischemic stroke carotid artery dissection is a common cause of stroke in young patients classic presentation of a chronic audio dissection include local pain to that area an ipsy lateral headache to one side or to the neck an ipsilateral horner syndrome ischemic stroke and retinal ischemia the current gold standard first line investigation is digital subtraction and geography and this is a fluoroscopic technique which enables visualization of the blood vessels the last clinical anatomy uh we're going to talk about is amaurosis fujax and i'm probably pronouncing that last part wrong amorosis fujax from the greek amaurosis meaning dark and latin fugax meaning fleeting is a temporary loss of vision in one or both eyes caused by a blocked blood vessel the most common cause of the blocked blood vessel is a cholesterol plaque or blood clot and most cases are due to stenosis of the ipsilateral carotid artery the carotid artery on the same side of the eye symptoms the symptoms of amaurosis fujex are partial or complete loss of vision in one or both eyes that is sudden painless and temporary the vision loss is often referred to as curtain visual loss as it appears like a vertical curtain coming down over the eye before resolving over several minutes even though this vision loss is temporary patients experiencing amaurosis few jacks are at risk of strokes so in summary in this video we talked about the carotid arteries which are major blood vessels that supply blood to the brain neck and face we discussed that there are two carded arteries one on each side of the body and the fact that in the neck each common carotid artery branches into two divisions the external carotid artery that supplies blood to the head and neck external to the cranium and then the internal credit artery that supplies blood to the brain eyes and forehead we also discussed why the carotid arteries are clinically important and relevant such as in the conditions of carotid artery hypersensitivity carotid plaques carotid artery aneurysm carotid artery dissections and amaurosis few jacks thank you for watching you