What are the Major Blood Vessels that run through the Head and the Neck?
The carotid arteries are the primary blood vessels that supply the blood to the neck and regions of the neck, brain, and face. Among the carotid arteries, two are positioned on the left and the right. When it comes to the neck, there are two segmental regions of the carotid arteries:
- The internal carotid artery serves as the blood supplier to the brain.
- The external carotid artery serves as the blood supplier to the neck and the face.
Tissue Layers in the Carotid Artery
Similar to all arteries, three layers of tissues are present within the carotid arteries. These are:
- The smooth innermost layer intima.
- The muscular middle layer media.
- The outer layer adventitia.
The carotid bulb is the widened portion of the carotid artery in the main branch point. The carotid sinus is also known as the carotid bulb and works as a sensor to mediate blood pressure. Carotid artery pulse is generally felt against the windpipe in the neck region.
The right carotid sub division originates from the bifurcation of the brachiocephalic trunk. This bifurcation occurs approximately at the level of the right side of the sternoclavicular joint. The left carotid artery starts directly from the arch of the aorta. Together, the right and left segments of the carotid artery travel upwards to the neck, laterally to the esophagus and the trachea. However, they do not branch inside the neck portion.
In the superior margin portion of the thyroid cartilage, the carotid arteries further branch into internal and external carotid arteries, which have different functions. This same region of the division is known as the carotid triangle. The internal carotid is slightly fused with the common carotid, and they seem dilated, and this region is called the carotid sinus. This zone essentially detects the changes and regulates blood pressure.
External Carotid Artery
The arteries directed towards the regions of the neck and head external to the skull are known as the external carotid arteries. After originating from the common carotid artery, the external carotid artery passes through the neck, the posterior part of the neck, the mandibular portion, and the ear's anterior lobule region. The artery ends inside the parotid glands by splitting into the temporal artery, maxillary artery, and superficial artery.
The following are the six branches:
- Superior thyroid artery
- Facial artery
- Occipital artery
- Posterior auricular artery
- Ascending pharyngeal artery
- Lingual artery
The facial, superficial, and maxillary arteries are the main branches of the arteries because the maxillary artery supplies the blood to the deep structures of the face. In contrast, the temporal and facial arteries supply blood to the superficial portion of the face.
Internal Carotid Artery
The internal carotid artery does not provide blood to any structures like the neck. It enters the cranial cavity through the carotid canal in the petrous portion of the temporal bone. Inside the cranial cavity, the internal carotid artery supplies blood to the eyes, forehead, and brain.
Other Arteries of the Neck and Head
The vertebral arteries originate from the subclavian arteries, which are the arteries of the thorax that remain below the clavicles. The vertebral arteries move upwards through the neck inside the transverse portion of the cervical vertebrae. There is no separation between the internal carotid circulations and the vertebral artery circulations. They attach to the cerebral arterial circle positioned within the skull, more precisely at the bottom portion of the brain.
The thyrocervical trunk is yet another artery that supplies blood to the neck portion. It has the same origin as the subclavian artery, which further branches into ascending, transverse, inferior, and suprascapular arteries.
Veins of the Head and Neck
The veins are yet another major blood vessels that connect the neck and head. However, the veins drain the blood out from the head and neck. Some of the major veins are facial veins, external and internal jugular veins, inferior veins, and vertebral veins.
Carotid Artery Conditions
- Carotid artery vasculitis: This is an inflamed condition of the carotid artery caused by an infection or other autoimmune conditions.
- Stroke: When the blood flow through the carotid artery stops suddenly, it results in a stroke because the blood supply to the brain is stopped. Sometimes, cholesterol can deposit as plaque in the carotid artery and cause a stroke.
- Carotid artery stenosis: When the carotid artery gets narrow due to plaque buildup, it results in stenosis. This condition does not manifest as symptoms till it becomes very severe.
- Carotid artery aneurysm: A part of the artery becomes bulged like a balloon, and when it ruptures, excessive bleeding starts. There is always a risk of rupture of these aneurysms.
- Carotid artery embolism: A plaque fragment or cholesterol is called an embolus, and it has the potential to break off from the carotid artery and gets carried by the blood to the brain, resulting in a stroke.
- Carotid artery atherosclerosis: There can be a gradual buildup of plaque in the walls of the carotid arteries over some time. As a result, the carotid artery narrows and could lead to a stroke.
- Amaurosis fugax: Blindness in a single eye is temporary and occurs due to an embolus breaking off from the carotid artery wall and getting stuck inside the artery, which supplies blood to the eye.
- Temporal arteritis: This is an autoimmune condition where the carotid branches become swollen, called vasculitis. Consequently, extreme headaches develop on either side of the head, which radiates to the jaws and neck and manifests as pain while chewing food.
- Carotid hypersensitivity syndrome: For a few people, when the carotid sinus exerts pressure, it can cause them to faint as there will be a sudden drop in blood pressure. These symptoms are predominant while shaving or wearing a tight collared shirt.
Context and Applications
Blood vessels of the head and neck are essential in professional coursework of both undergraduate and graduate programs such as
- Bachelors of Science in Biology
- Bachelors of Science in Zoology
- Bachelors of Science in Medicine
- Master of Science in Biological Sciences
- Master of Science in Human Anatomy and Physiology
- Master of Science in Biotechnology
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