Head and Neck Vein Arteries & Nerves

Major Arteries Supplying the Head and Neck

• Common Carotid Artery: This major artery bifurcates (splits) into the internal and external carotid arteries at the level of the upper border of the thyroid cartilage (C4 vertebra). It lies adjacent to the jugular vein and within the carotid sheath alongside the vagus nerve.
• Internal Carotid Artery: Primarily supplies the brain and eyes.
• External Carotid Artery: Supplies the face, scalp, neck, and thyroid gland; excluding the brain. It branches into several smaller arteries including:
  • Maxillary Artery: Considered the main artery supplying the maxillary and mandibular teeth. It branches into the inferior alveolar artery, supplying the mandibular teeth. The maxillary artery also gives rise to the Greater Palatine Artery, supplying the hard palate, an artery relevant in dental procedures.
  • Facial Artery: Supplies the lower jaw, lips, and nose.
  • Lingual Artery: Supplies the tongue, a structure relevant in dental examinations.
  • Occipital Artery: Supplies the scalp and areas behind the ear.

Major Veins Draining the Head and Neck

• Internal Jugular Vein: Drains blood from the brain, face, and tongue, excluding the posterior part of the scalp. It lies within the carotid sheath, along with the common carotid artery and vagus nerve. It joins the subclavian vein behind the clavicle to form the brachiocephalic vein.
• External Jugular Vein: Drains blood from the face and scalp. It is formed by the union of the posterior auricular and retromandibular veins.
• Vertebral Vein: Primarily drains the upper neck and spinal cord region.
• Pterygoid Plexus: Located within the infratemporal fossa, drains blood from the maxillary and mandibular teeth, as well as the muscles of mastication. It also drains blood from the orbit and nasal cavity. It lacks valves, risking potential backflow and infection spread.
• Retromandibular Vein: Drains the superficial structures of the scalp and face.

Cranial Nerves Relevant to Dentistry

• Olfactory Nerve (CN I): Responsible for the sense of smell.
• Optic Nerve (CN II): Supplies the eye.
• Oculomotor Nerve (CN III), Trochlear Nerve (CN IV), and Abducens Nerve (CN VI): All contribute to controlling eye movements.
• Trigeminal Nerve (CN V): A very important nerve in dentistry. It has three main branches:
  • Ophthalmic Nerve (V1): Supplies the upper eyelid, forehead, and part of the nose. Relevant in dental procedures due to its connection to the maxillary sinus.
  • Maxillary Nerve (V2): Supplies the upper teeth, palate, and maxillary sinus. A concern during dental procedures due to its proximity to the maxillary sinus.
  • Mandibular Nerve (V3): Supplies the lower teeth, jaw, and muscles of mastication (chewing). It is targeted in local anesthesia procedures for lower molars.
• Facial Nerve (CN VII): Responsible for facial expression and taste on the anterior two-thirds of the tongue.
• Glossopharyngeal Nerve (CN IX): Supplies the posterior third of the tongue and pharynx. Also responsible for taste sensation on the posterior third of the tongue.
• Accessory Nerve (CN XI): Innervates the sternocleidomastoid and trapezius muscles, relevant to shoulder and neck movement.
• Hypoglossal Nerve (CN XII): Innervates the muscles of the tongue, important in dental examinations and procedures.

Head and Neck Arteries

• The common carotid artery supplies blood to the head and neck, bifurcating into the internal carotid artery and external carotid artery.
• The internal carotid artery supplies the brain and eyes.
• The external carotid artery supplies the face, scalp, and neck.
• The maxillary artery, a branch of the external carotid artery, supplies the maxillary and mandibular teeth.
• The inferior alveolar artery supplies blood to the mandibular teeth and is a branch of the maxillary artery.
• The facial artery supplies the lower jaw, lips, and nose.
• The lingual artery supplies blood to the tongue.
• The occipital artery supplies the scalp and areas behind the ear.

Head and Neck Veins

• The internal jugular vein is the primary vein that drains blood from the brain, face, and neck.
• The external jugular vein drains blood from the face and scalp.
• The pterygoid plexus is a network of veins in the infratemporal fossa and drains the maxillary and mandibular teeth.
• The retromandibular vein drains the superficial structures of the scalp and face.
• The vertebral vein drains structures in the upper neck and spinal cord region.

Cranial Nerves

• Olfactory nerve (CN I) is responsible for the sense of smell.
• Optic nerve (CN II) supplies the eye.
• Oculomotor nerve (CN III) controls eye movement.
• Trochlear nerve (CN IV) controls eye movement.
• Abducens nerve (CN VI) controls eye movement.
• **Trigeminal nerve (CN V) ** has three branches: ophthalmic (V1), maxillary (V2), and mandibular (V3).
• Facial nerve (CN VII) controls facial expression and taste sensation on the anterior two-thirds of the tongue.
• Glossopharyngeal nerve (CN IX) supplies the posterior third of the tongue and pharynx.
• Accessory nerve (CN XI) innervates the muscles of the shoulder and neck.
• Hypoglossal nerve (CN XII) innervates the muscles of the tongue.

Dental Considerations

• The greater palatine artery, a branch of the maxillary artery, supplies blood to the hard palate.
• The inferior alveolar artery runs close to the inferior alveolar nerve and must be considered during inferior alveolar nerve blocks to avoid hematoma formation.
• The pterygoid plexus can spread dental infections due to its lack of valves.
• The facial vein drains into the internal jugular vein, explaining the potential spread of infection to the brain.

Summary

The head and neck regions are complex, with many arteries, veins, and cranial nerves responsible for various functions. Understanding their anatomy and relationships is critical for dental professionals to understand anatomy and ensure safe procedures.