Blood Supply of the Head and Neck: Arteries and Veins Explained

The human neck and the head are also some of the most vascularized parts of the body. The presence of a well-developed system of arteries and veins also provides the brain, face, and sense organs with sufficient oxygen and nutrients and helps to remove the metabolic waste. The blood circulation of these fields is extremely important to the medical practitioners especially in cases of surgery, trauma treatment, and cardiovascular conditions. This paper discusses the great arteries and veins of the head and neck with special focus on the carotid arteries, jugular veins and their clinical value.

According to Online Medical Encyclopaedia, the blood flow in the head and the neck may be further subdivided into two main systems: the arterial or the blood system that supplies the tissues with oxygenated blood and the venous system that transfers the deoxygenated blood back to the heart. The two systems are highly interdependent and anatomy plays a vital role in ensuring that the brain functions well, the facial expression, and sensory perception.

The brain itself uses approximately 20 percent of all the oxygen in the body and this shows the significance of unbroken arterial circulation. Any impairment in this circulation like by blockage or injury would result in neurological losses, strokes, or life-threatening illnesses.

Exhibitors of the Great Arteries of the Head and Neck.

The carotid arteries are the main blood vessels that serve the head and the neck. They arise out of the aorta (on the left side) and the brachiocephalic trunk (on the right side) which then divide into other smaller arteries, which supply a particular area.

Common Carotid Artery

The common carotid artery (CCA) originates in the neck within the carotid sheath with the internal jugular vein as well as the vagus nerve. At approximately the fourth cervical arch it divides into:

• Internal carotid artery(ICA): serves the brain and the eyes.
• External carotid artery (ECA): It serves the face, the scalp and neck.

Internal Carotid Artery

ICA is an important cerebral vessel. It passes through the carotid canal of the temporal bone, flows into the cranial cavity and even fuses with the circle of Willis, arterial ring at the bottom of the brain which offers collateral circulation. Major branches include:

• Ophthalmic artery – serves the eye and orbit.
• The anterior cerebral artery – serves the medial and superior frontal lobes.
• Middle cerebral artery – serves the lateral walls of the brains.

It does not have any branches in the neck; it is largely intracranial and therefore of great significance in brain perfusion.

External Carotid Artery

The external carotid artery has many branches, which serve the face, jaw, scalp and neck muscles. Major branches include:

1. Superior thyroid artery- supplies the thyroid gland and larynx.
2. Lingual artery- serves the tongue.
3. Facial artery- serves the muscles of the face.
4. Occipital artery – is a supply to the back of the head.
5. Maxillary artery – has a supply to the deep structures of the face, such as teeth and the nasal cavity.
6. STA – serves the scalp and the temporal area.

Of special interest in terms of surgical planning is the external carotid artery, which is used in the maxillofacial surgery and management of traumatic bleeding in faces.

Vertebral Arteries

The subclavian arteries give way to the vertebral arteries which pass through the transverse foramina of the cervical vertebrae. They pass through the foramen magnum to the cranial cavity where they are united into the basilar artery that serves the posterior circulation of the brain. The arteries of the spine play a crucial role in the provision of the brainstem, the cerebellum, and the posterior cerebrum.

Venous System of the Head and Neck

The blood flow of the head and neck is a complement to the supplying arteries, and the deoxygenated blood and metabolic wastes are efficiently removed. The veins of this region are usually variable in course and network as compared to those in the arteries.

Internal Jugular Vein

The major pathway of venous return in the brain, face and neck is the internal jugular vein (IJV). It courses on the common carotid artery of the carotid sheath and empties into the brachiocephalic vein. Tributaries include:

• Facial vein – empties superficial facial buildings.
• Lingual vein – drains the tongue.
• Pharyngeal veins – empty the pharynx and the muscles around the pharynx.

The IJV has great clinical significance in central venous access, intracranial pressure monitoring and neck surgery.

External Jugular Vein

External jugular vein (EJV): It is superficial to the muscle of the sterna cleavage and empties the scalp, the superficial face, and the neck. It drains in the subclavian vein, and is an obvious landmark in trauma and diagnostic studies.

Venous Sinuses

The brain of the skull empties into a system of dural venous sinuses, which include:

• Superior sagittal sinu – drains the upper most part of the brain.
• Transverse sinu – flows in the sigmoid sinu and ultimately flows in the IJV.
• Cavernous sinu – is connected to facial veins, through ophthalmic veins.

These are sinuses that do not have valves to allow the movement of flow in both directions, and this at times facilitates transmitting the infections to the brain through the face.

Clinical Significance

The information about the blood supply of the head and neck is important in various clinical situations:

Surgery

Surgical procedures of the head and neck (thyroidectomy, carotid endarterectomy, and facial reconstructive surgery) demand accurate understanding of arterial and venous structures to prevent such complications as stroke, excessive hematoma or nerve damage.

Trauma Management

Carotid arteries and jugular veins may suffer traumatic injuries to the neck. Timely diagnosis and treatment is needed to avoid fatal hemorrhage or ischemia of the brain.

Cardiovascular Health

The carotid arteries are usually affected by atherosclerosis. A constriction of these arteries may decrease blood flow in the brain and may predispose to transient ischemic attacks (TIAs) and strokes. Early detection and intervention is possible due to regular assessment, such as ultrasound or angiography.

Neurology

Blockage of the blood circulation by internal carotid or vertebral arteries may cause stroke, cerebral infarction or transient neurological deficit. Such knowledge of the collateral pathways in the circle of Willis assists the clinicians in foreseeing clinical outcomes and strategy formulation.

Connection of the Arteries and veins.

The arteries and veins tend to run in complex networks with the head and the neck having a complex network of vascular sheaths. This connection in the body permits free flow of heat, oxygen and nourishment. Nevertheless, it also poses the possible risks, including arteriovenous fistulas or infection.

An example is that the ophthalmic veins connect the cavernous sinu to the facial vein. This valveless connection has the ability to transmit the infection of the so-called danger triangle of the face (nose and upper lip) to the brain, which can lead to the development of life-threatening complications.

Summary of Key Vessels

Conclusion

The blood flow of the neck and the head is a very intricate system of vessels, the carotid arteries and the jugular veins having the predominant part in it. The knowledge of this anatomy is essential to medical practitioners who deal with surgeries, trauma, cardiovascular conditions, and neurological conditions. The combination of the arteries and the veins makes it such that the brain and the facial structure are properly perfused as waste gets properly eliminated. Effective knowledge of such vessels does not only increase the quality of patient care but also reduces the chances of developing complications in both elective and emergency departments.

The study of these vessels in more detail will emphasize the high level of human anatomy and the reasons why small disturbances in blood circulation may create serious clinical implications.