24.26:
Arteries of the Head and Neck
Blood supply to the head and neck is provided by the common carotid arteries and branches of the subclavian artery.
The common carotid arteries, which have the broadest distribution, divide into the external and internal carotid arteries.
The external carotid arteries reach most tissues of the head, except for the brain and orbits. They branch into various smaller arteries supplying the thyroid gland, larynx, tongue, anterior face, posterior scalp, and jaws.
The internal carotid arteries supply over 80% of the cerebrum and the orbits. They enter the cranium and branch into the ophthalmic artery, which further divides into the anterior and middle cerebral arteries.
From the subclavian arteries, the vertebral arteries rise in the neck, and their branches reach the vertebrae, spinal cord, and several deeper neck structures.
Inside the cranium, the right and left vertebral arteries merge, forming the basilar artery, which supplies blood to the cerebellum, pons, and inner ear.
The thyrocervical and costocervical trunks from the subclavian artery supply the thyroid gland, cervical vertebrae, spinal cord, scapular muscles, neck, and superior intercostal muscles.
24.26:
Arteries of the Head and Neck
The human body's intricate network of arteries ensures that every organ system receives the necessary oxygen and nutrients for optimal function. The arterial network in the head and neck region is particularly complex, providing vital blood flow to the brain, eyes, and other critical structures. Prominent arteries in this region include the internal carotid arteries and the vertebral arteries.
The internal carotid arteries supply blood to the anterior portion of the cerebrum. They enter the cranial cavity through the carotid foramen and give rise to several branches, including the anterior cerebral artery, which nourishes the frontal lobe of the cerebrum. Another crucial branch, the middle cerebral artery, supplies blood to the temporal and parietal lobes. These areas are particularly susceptible to cerebrovascular accidents (CVAs), highlighting the importance of these arteries.
The vertebral arteries primarily supply blood to the posterior portion of the brain. The basilar artery, formed by the union of the two vertebral arteries, provides blood to the brain stem and sends branches to the cerebellum, ultimately bifurcating into the posterior cerebral arteries that contribute to the posterior part of the arterial circle.
The arterial circle, or circle of Willis, is a critical structure in the brain's vasculature. This circular anastomosis of arterial branches ensures a continuous blood supply to the brain, even when one of the main arteries is blocked. This redundancy serves as a safeguard against potential ischemic events, such as strokes, and represents a testament to the body's resilience and complex design.
From a clinical perspective, the arteries of the head and neck hold significant importance. For instance, any occlusion in the internal carotid artery or its branches can lead to a transient ischemic attack (TIA) or a stroke, resulting in loss of consciousness or temporary loss of neurological function. The severity of these events underscores the critical role these arteries play in maintaining the brain's health. Additionally, the ophthalmic artery, another branch of the internal carotid artery, supplies blood to the eyes. Any disruption in its blood flow can lead to serious vision problems.
In conclusion, understanding the intricacies of the arterial system in the head and neck region is paramount, not only for appreciating the body's extraordinary design but also for managing and treating cerebrovascular diseases effectively.