Lesson V: Major Blood Supply of the Head and Neck

Blood Supply to the Head and Neck It is important to be able to locate the larger blood vessels of the head and neck because these vessels may become compromised by disease or during such dental procedures as local anesthetic injections. Blood vessels may also spread infection in the head and neck. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2

Blood Supply to the Head Define Arteries: Blood vessels carry blood from the heart to other parts of the body Primarily carry oxygenated blood

Blood Supply to the Head Define Veins: A blood vessel that carries blood that is low in oxygen from the body back to the heart.

Major Arteries of the Face and Oral Cavity The aorta ascends from the left ventricle of the heart. The common carotid artery arises from the aorta and subdivides into the internal and external carotid arteries. The internal carotid artery supplies blood to the brain and eyes. The external carotid artery provides the major blood supply for the face and mouth. When you take your pulse in your neck, you are checking the carotid artery. ders, an imprint of Elsevier Inc. All rights reserved. 6

Branches of the External Carotid Artery Facial Artery Supplies blood to the skin and muscles of facial expression Sends out branches to the upper and lower lips Sends out branch to side of nose Lingual Artery Branches off the external carotid artery below the facial artery Supplies blood to tongue and floor of the mouth Maxillary Artery There are about 15 branches to this artery Supplies muscles of mastication Supplies the teeth Supplies oral and nasal cavities

Branches of the External Carotid Artery Mental Artery The mental branch escapes with the nerve at the mental foramen, supplies the chin. It supplies the buccal gingiva and mucosa of the lower lip Buccal Branch – Runs downward and forward to supply the mucosa of the cheek and the buccal mucosa and gingiva of maxillary and mandibular posterior teeth.

Major veins Jugular Veins Three divisions of importance in dentistry Internal: drains entire brain area Corresponds to the common carotid artery External: continues the descent down the neck Terminates in the subclavian vein Anterior: drains into the external jugular vein before it joins the subclavian veins

Major Veins Maxillary vein Collects blood from the pterygoid plexus It merges with the temporal vein to drain and form the retromandibular vein Plexis -network of nerves, blood vessels, or other vessels in the body

Major Veins Retromandibular Vein Formed from merger of maxillary and temporal vein It emerges from the parotid gland and moves downward Retromandibular Vein

Important Terms related to blood supply Define Plexus Hemorrhage Hematoma Embolus Thrombus Bacteremia Aneurysm

Plexus- a large network of blood vessels

Hemorrhage; large amounts of blood escapes into surrounding tissues without clotting

Hematoma- small amounts of blood that escape into surrounding tissues causing bruising

Embolus- a foreign body (blood clot) that travels within the body and can constrict blood flow

Thrombus- a blood clot, a lesion attached to the inner vessel wall, can block partially or fully the flow of blood Thrombus- a blood clot, a lesion attached to the inner vessel wall, can block partially or fully the flow of blood

Bacteremia- bacteria introduced into the blood stream

Aneurysm An aneurysm occurs when part of a blood vessel (artery) or cardiac chamber swells, - either the blood vessel is damaged or there is a weakness in the wall of the blood vessel. As blood pressure builds up it balloons out at its weakest point. The swelling can be quite small or very large - when large it tends to extend along the blood vessel. As the aneurysm grows there is a greater risk of rupture - this can lead to severe hemorrhage, and other complications, including sudden death.