Vascular Anatomy of the Neck
The neck holds the vital arteries transmitting blood to the brain, head and face. It also transmits the veins which drain the deoxygenated blood from the brain, head and face and return it to the right side of the heart. The neck also includes the cervical spinal cord, as well as some significant cranial nerves. Some of these structures travel together in a facial sheath called the carotid sheath. The carotid sheath carries the common and internal carotid arteries, the internal jugular vein, the vague nerve, some lymph nodes, carotid per arterial plexuses and the carotid sinus nerve.
Vascular Anatomy of the neck the main artery in the neck is the ordinary carotid artery, which separate at the upper border of the thyroid cartilage of the larynx (C4). The left general carotid artery branches straight off the aortic arch and extends into the neck. The right general carotid artery has a different initial course. It is a branch of the brachiocephalic trunk. The brachiocephalic trunk is the first branch of the aortic arch and it bifurcates into the right subclavian artery and the right common carotid artery. Both ordinary carotid arteries ascend in the neck lying medially in the carotid sheath.
Near the bifurcation of the general carotid arteries, there are two important receptors, the carotid sinus and the carotid body. The carotid sinus is a bar receptor which senses the pressure in the carotid artery system and transmits information to the brain about the blood pressure in order to maintain blood pressure homeostasis. It is located at the beginning of the internal carotid artery as a small dilatation. The carotid body is a small lump of tissue that lies on the medial side of the ordinary carotid bifurcation. Its role is to monitor the levels of oxygen in the blood; it relays information about blood oxygen to the brain. In accordance with the changes sensed by the carotid body, the brain responds by changing the rate of breathing.
The internal carotid artery is the main supplier of blood to the brain. It arises from the ordinary carotid artery in the neck, and courses posterior to the external carotid artery. The internal carotid artery does give off any branches in the neck. It ascends into the cranial cavity throughout the carotid canals in the petro us part of the temporal bone.
The external carotid artery is the other branch of the general carotid artery after it bifurcates at the upper border of the thyroid cartilage. It lies anterior to the internal carotid artery. It ascends in the neck and enters the parotid gland on the face, where it separate into the maxillary artery and the superficial temporal arteries. The external carotid supplies parts of the neck face and scalp primarily. However, the middle meningeal artery is a branch which supplies the dura mater; the tough, outer meningeal covering of the brain. Unlike the internal carotid artery, the external carotid gives off a number of branches in the neck. Close to the bifurcation, the superior thyroid artery branches from the external carotid. It travels in an antero-inferior direction as it descends to supply the thyroid gland. The superior laryngeal artery branches off the superior thyroid artery and supplies blood to the larynx. The superior thyroid artery also supplies blood to a number of neck muscles.
The next branch from the outside carotid artery is the lingual artery, which arises close to the middle pharyngeal constrictor muscle. It supplies blood to parts of the tongue, and gives rise to the sublingual artery and the deep lingual artery. From its origin, it passes upwards and anteriorly. It travels deep to the hypoglossal nerve for part of its course.
The facial artery is an anterior branch of the external carotid artery. It generally arises above the lingual artery, but in some people, these arteries share a common origin. The facial artery gives off two important branches in the neck; the ascending palatine artery and the tonsillar artery, which supply the tonsils, the soft palate and nearby structures. It then travels underneath muscles in the upper neck and lower jaw, and pierces the submandibular salivary gland, which it supplies.