Arteries Of Head And Neck Flowchart

Navigating the intricate network of arteries supplying the head and neck can feel like traversing a complex map. This intricate system ensures a constant flow of oxygen and nutrients to the brain, face, and surrounding structures, making it crucial for proper function and survival. Understanding the branching pattern of these arteries is essential for medical professionals in various fields, including neurology, surgery, and radiology. Let's embark on a journey through the arterial landscape of the head and neck, visualized as a comprehensive flowchart.

The Aortic Arch: The Starting Point

Our journey begins at the aortic arch, the origin of the major arteries supplying the entire body, including the head and neck. From the aortic arch, three main branches emerge:

• Brachiocephalic Trunk (Innominate Artery): This is the first and largest branch arising from the aortic arch.
• Left Common Carotid Artery: This artery arises directly from the aortic arch, positioned to the left of the brachiocephalic trunk.
• Left Subclavian Artery: This artery is the third branch originating directly from the aortic arch.

The brachiocephalic trunk further divides into two critical arteries:

• Right Common Carotid Artery: Supplies the right side of the head and neck.
• Right Subclavian Artery: Supplies the right arm and also gives rise to branches that contribute to the blood supply of the neck and brain.

The Common Carotid Arteries: Ascending to the Head

Both the right and left common carotid arteries ascend in the neck, running alongside the trachea and esophagus. At the level of the upper border of the thyroid cartilage (approximately C3-C4 vertebral level), each common carotid artery bifurcates into two main branches:

• External Carotid Artery (ECA): Supplies the face, scalp, oral cavity, and other external structures of the head and neck.
• Internal Carotid Artery (ICA): Primarily supplies the brain, as well as the eyes and forehead.

The External Carotid Artery (ECA): Feeding the Face and Scalp

The external carotid artery is the workhorse for the superficial structures of the head and neck. It gives off numerous branches along its course, each supplying a specific region. Remembering the branches of the ECA can be aided by mnemonics; one popular one is: "Some Anatomists Like Freaking Out Poor Medical Students." This translates to:

• Superior Thyroid Artery: Supplies the thyroid gland and larynx.
• Ascending Pharyngeal Artery: Supplies the pharynx, soft palate, and meninges.
• Lingual Artery: Supplies the tongue.
• Facial Artery: Supplies the face.
• Occipital Artery: Supplies the posterior scalp and neck.
• Posterior Auricular Artery: Supplies the scalp behind the ear and the auricle.
• Maxillary Artery: One of the two terminal branches; supplies the deep structures of the face, including the maxilla, mandible, teeth, and muscles of mastication.
• Superficial Temporal Artery: The other terminal branch; supplies the lateral scalp.

Let's delve into some of the key branches of the ECA in more detail:

• Facial Artery: This artery has a winding course across the face. It arises from the ECA just above the lingual artery and passes over the inferior border of the mandible. Its branches include the inferior labial, superior labial, and angular arteries, which supply the lips and nose, respectively. Palpation of the facial artery is possible as it crosses the mandible, making it a useful site for checking the pulse.

• Maxillary Artery: This is the larger of the two terminal branches of the ECA. It has a complex course, passing deep to the ramus of the mandible and entering the infratemporal fossa. It supplies a wide range of structures, including the muscles of mastication (temporalis, masseter, medial and lateral pterygoids), the teeth, the palate, and the nasal cavity. Some important branches of the maxillary artery include:

  • Middle Meningeal Artery: This artery is clinically significant because it enters the skull through the foramen spinosum and supplies the dura mater. Rupture of the middle meningeal artery is a common cause of epidural hematoma, a life-threatening condition.
  • Inferior Alveolar Artery: Supplies the lower teeth.
  • Infraorbital Artery: Supplies the upper teeth and the skin below the orbit.

• Superficial Temporal Artery: The smaller terminal branch of the ECA, it ascends in front of the ear and supplies the lateral scalp. It can be palpated easily in front of the ear. Temporal arteritis, an inflammatory condition affecting the superficial temporal artery, can cause headaches and visual disturbances.

The Internal Carotid Artery (ICA): Nourishing the Brain

The internal carotid artery has no branches in the neck. It ascends into the skull through the carotid canal in the temporal bone. After entering the cranial cavity, the ICA gives off several important branches that supply the brain, eye, and forehead. The ICA is divided into several segments: cervical, petrous, cavernous, and cerebral.

• Ophthalmic Artery: This is the first major branch of the ICA within the cranial cavity. It enters the orbit through the optic canal and supplies the eye and surrounding structures, including the eyelids, forehead, and nose. Important branches of the ophthalmic artery include:

  • Central Retinal Artery: Supplies the retina. Occlusion of the central retinal artery can lead to sudden blindness.
  • Lacrimal Artery: Supplies the lacrimal gland.

• Posterior Communicating Artery (PComm): This artery connects the ICA to the posterior cerebral artery (PCA), which is a branch of the basilar artery (derived from the vertebral arteries). The PComm is a crucial component of the Circle of Willis, a vital arterial anastomosis at the base of the brain.

• Anterior Choroidal Artery: Supplies the choroid plexus, hippocampus, and internal capsule.

• Anterior Cerebral Artery (ACA): Supplies the medial aspect of the cerebral hemispheres, including the frontal and parietal lobes. It is connected to the opposite ACA by the anterior communicating artery (AComm), another component of the Circle of Willis.

• Middle Cerebral Artery (MCA): This is the largest branch of the ICA and the most commonly affected artery in stroke. It supplies the lateral aspect of the cerebral hemispheres, including the motor and sensory cortex areas responsible for the face, arm, and hand.

The Subclavian Artery: Contributing to the Brain and Neck

As mentioned earlier, both the right and left subclavian arteries arise from different origins (brachiocephalic trunk and aortic arch, respectively). The subclavian artery primarily supplies the upper limb, but it also gives off branches that contribute to the blood supply of the neck and brain:

• Vertebral Artery: This is the most important branch of the subclavian artery in relation to the head and neck. It ascends through the transverse foramina of the cervical vertebrae (C6-C1) and enters the skull through the foramen magnum. The vertebral arteries join to form the basilar artery at the base of the brain.

• Thyrocervical Trunk: This short trunk gives off several branches, including the inferior thyroid artery, which supplies the lower part of the thyroid gland.

The Vertebral-Basilar System: Supplying the Posterior Brain

The vertebral arteries ascend through the neck, passing through the transverse foramina of the cervical vertebrae. They enter the cranial cavity through the foramen magnum and unite to form the basilar artery at the level of the pons.

• Basilar Artery: This artery ascends along the ventral surface of the pons and divides into the two posterior cerebral arteries (PCAs). The basilar artery gives off several branches that supply the brainstem, cerebellum, and inner ear. Some important branches include:

  • Anterior Inferior Cerebellar Artery (AICA): Supplies the cerebellum and brainstem.
  • Posterior Inferior Cerebellar Artery (PICA): Supplies the cerebellum and medulla oblongata. Occlusion of the PICA can lead to lateral medullary syndrome (Wallenberg syndrome).
  • Superior Cerebellar Artery (SCA): Supplies the cerebellum and midbrain.

• Posterior Cerebral Artery (PCA): Supplies the occipital lobe (visual cortex) and the inferior aspect of the temporal lobe. As mentioned earlier, the PCA is connected to the ICA via the posterior communicating artery, completing the Circle of Willis.

The Circle of Willis: A Vital Anastomosis

The Circle of Willis is a crucial arterial anastomosis located at the base of the brain. It connects the anterior (ICA) and posterior (vertebral-basilar) circulations, providing collateral circulation in case of blockage or narrowing of one of the major arteries. The Circle of Willis is formed by:

• Anterior Cerebral Artery (ACA)
• Anterior Communicating Artery (AComm)
• Internal Carotid Artery (ICA)
• Posterior Communicating Artery (PComm)
• Posterior Cerebral Artery (PCA)

The Circle of Willis is not always complete in all individuals, and variations in its anatomy are common. However, its presence provides a crucial safety mechanism for maintaining blood flow to the brain.

Clinical Significance

Understanding the arterial anatomy of the head and neck is essential for diagnosing and treating a wide range of conditions, including:

• Stroke: Blockage or rupture of an artery supplying the brain can lead to stroke, causing neurological deficits depending on the affected area.
• Transient Ischemic Attack (TIA): A "mini-stroke" caused by a temporary blockage of an artery.
• Aneurysm: A weakened and bulging area in the wall of an artery. Rupture of an aneurysm can lead to subarachnoid hemorrhage, a life-threatening condition.
• Arteriosclerosis: Hardening and narrowing of the arteries, which can increase the risk of stroke and other cardiovascular diseases.
• Temporal Arteritis: Inflammation of the temporal artery, causing headaches and visual disturbances.
• Carotid Artery Stenosis: Narrowing of the carotid artery, which can increase the risk of stroke.
• Head and Neck Tumors: Tumors in the head and neck region can compress or invade arteries, affecting blood flow.
• Trauma: Injuries to the head and neck can damage arteries, leading to bleeding and ischemia.

Flowchart Summary: Arteries of the Head and Neck

To summarize, let's create a simplified flowchart representation of the arterial supply to the head and neck:

Aortic Arch

• Brachiocephalic Trunk
  • Right Common Carotid Artery
    • Right External Carotid Artery
      • Superior Thyroid Artery
      • Ascending Pharyngeal Artery
      • Lingual Artery
      • Facial Artery
      • Occipital Artery
      • Posterior Auricular Artery
      • Maxillary Artery
        • Middle Meningeal Artery
        • Inferior Alveolar Artery
        • Infraorbital Artery
      • Superficial Temporal Artery
    • Right Internal Carotid Artery
      • Ophthalmic Artery
        • Central Retinal Artery
        • Lacrimal Artery
      • Posterior Communicating Artery (Circle of Willis)
      • Anterior Choroidal Artery
      • Anterior Cerebral Artery (Circle of Willis)
      • Middle Cerebral Artery
  • Right Subclavian Artery
    • Vertebral Artery
      • Basilar Artery
        • Anterior Inferior Cerebellar Artery (AICA)
        • Posterior Inferior Cerebellar Artery (PICA)
        • Superior Cerebellar Artery (SCA)
        • Posterior Cerebral Artery (Circle of Willis)
    • Thyrocervical Trunk
      • Inferior Thyroid Artery
• Left Common Carotid Artery
  • (Branches mirror the right common carotid artery)
• Left Subclavian Artery
  • Vertebral Artery
    • (Branches mirror the right subclavian artery)

This flowchart provides a simplified overview of the complex arterial network. In reality, there are numerous variations and anastomoses that can occur.

Advanced Imaging Techniques

Modern imaging techniques, such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA), play a crucial role in visualizing the arteries of the head and neck. These techniques allow physicians to identify blockages, aneurysms, and other abnormalities. Digital subtraction angiography (DSA) is an invasive technique that provides high-resolution images of the arteries and is often used to guide interventions, such as angioplasty and stenting.

Conclusion

The arterial supply to the head and neck is a complex and vital system. Understanding the branching patterns and clinical significance of these arteries is essential for medical professionals in various fields. By visualizing the arterial network as a flowchart, we can better appreciate its intricate design and the critical role it plays in maintaining brain function and overall health. From the aortic arch to the Circle of Willis, each artery plays a crucial role in delivering life-sustaining oxygen and nutrients. A disruption in this intricate system can have devastating consequences, highlighting the importance of recognizing and managing conditions that affect the arteries of the head and neck. Continuing advancements in imaging techniques and interventional procedures offer hope for improved diagnosis and treatment of vascular diseases affecting this vital region of the body.