Vascularization of the Head and Neck (Arteries and Veins)
📌 Blood supply to the head and neck originates primarily from two sources: the Common Carotid Artery and the Subclavian Artery.
📌 The Common Carotid Artery branches into the External Carotid Artery (supplying superficial structures like the face and scalp) and the Internal Carotid Artery (supplying the brain via the cranial cavity).
📌 The Vertebral Artery, a branch of the Subclavian Artery, ascends through the transverse foramina of the cervical vertebrae to supply the posterior circulation of the brain.
📌 Venous drainage generally follows the arteries; however, major veins like the Internal Jugular Vein (draining the deep structures/brain) and the External Jugular Vein (draining superficial structures) are key return paths to the heart via the Brachiocephalic Vein and Vena Cava Superior.

Vascularization of the Intracranial Structures (Brain)
📌 Intracranial arterial supply relies heavily on the Internal Carotid Artery and the Vertebral Arteries entering the cranium through the Carotid Canal and Foramen Magnum, respectively.
📌 These arteries form an interconnected network at the base of the brain called the Arterial Circle of Willis (Circulus Arteriosus), which features connections like the Posterior Communicating Artery.
📌 Major branches supplying the cerebrum include the Anterior Cerebral Artery, Middle Cerebral Artery, and Posterior Cerebral Artery.
📌 Venous drainage within the cranium converges into large channels called Dural Venous Sinuses (e.g., Superior Sagittal Sinus, Transverse Sinus), which eventually drain into the Internal Jugular Vein.

Innervation of the Head and Neck
📌 Cutaneous (skin) innervation for the superficial head and neck region is primarily managed by the Cervical Plexus, formed by cervical nerves C₁ to C₄, yielding branches like the Greater Auricular Nerve and Transverse Cervical Nerve.
📌 Motor innervation for facial muscles is supplied by the Facial Nerve (Cranial Nerve VII), which passes anterior to the Parotid Gland and branches extensively across the face.
📌 Muscles of mastication (chewing muscles) and deep structures receive innervation from the Mandibular Nerve, a branch of the Trigeminal Nerve.

Key Points & Insights
➡️ The Internal Carotid Artery and Vertebral Arteries are the two primary arterial sources providing blood flow to the brain structures within the cranial cavity.
➡️ The Arterial Circle of Willis functions as a critical site for anastomosis, ensuring collateral blood flow if one source is compromised.
➡️ The Facial Nerve (CN VII) is a purely motor nerve for the muscles of facial expression, running superficially near the Parotid Gland.
➡️ Superficial skin sensation in the neck region is derived from the Cervical Plexus ($\text{C}_1-\text{C}_4$), distributing sensory branches like the Supraclavicular Nerves.

📸 Video summarized with SummaryTube.com on Nov 20, 2025, 05:30 UTC