Facial Nerve & Blood Supply Quiz

Study Notes

Objectives

Understand the innervation and blood supply to the scalp and face.
Identify and discuss main branches of the facial nerve.
Explain the origin, course, and termination of the facial artery and facial vein.
Describe the blood supply patterns and venous drainage of the head and neck.

Scalp Anatomy

Extends from the supra-orbital margins anteriorly to the external occipital protuberance and superior nuchal lines posteriorly, and zygomatic arches on each side.
Composed of five layers: Skin, Connective Tissue, Aponeurotic layer, Loose Areolar Tissue, and Pericranium.

Layers of the Scalp

Skin: Thick, hairy, contains sebaceous and sweat glands; common site for sebaceous cysts.
Connective Tissue: Dense tissue housing superficial nerves and blood vessels.
Aponeurosis: Connects the frontal and occipital bellies of the occipitofrontalis muscle, allowing scalp movement.
Loose Areolar Tissue: Facilitates movement of the upper layers, contains emissary veins; considered a dangerous area.
Pericranium: Outer periosteum covering the skull's outer surface.

Muscles of the Scalp

The occipitofrontalis muscle consists of frontal and occipital bellies, connected by the aponeurotic tendon, responsible for raising eyebrows and moving the scalp.
The frontal belly is innervated by the temporal branch of the facial nerve (CN VII), while the occipital belly is innervated by the posterior auricular branch.

Sensory Nerve Supply of the Scalp

Anterior: Supratrochlear nerve (CN V1), Supraorbital nerve (CN V1), and Zygomaticotemporal nerve (CN V2), and Auriculotemporal nerve (CN V3).
Posterior: Great auricular nerve (C2, C3), Lesser occipital nerve (C2), Great occipital nerve (C2), and Third occipital nerve (C3).

Motor Nerve Supply of the Scalp

The occipitofrontalis muscle is supplied by the temporal and posterior auricular branches of the facial nerve.

Arterial Supply of the Scalp

Anterior: Supratrochlear artery and Supraorbital artery (both branches of Internal Carotid Artery), Superficial temporal artery (branch of External Carotid Artery).
Posterior: Posterior auricular artery and Occipital artery (both branches of External Carotid Artery).
Notable arterial anastomosis occurs between internal and external carotid arteries at the scalp.

Venous Drainage of the Scalp

Supratrochlear and supraorbital veins contribute to the angular vein.
Superficial temporal vein forms the retromandibular vein.
Posterior auricular vein drains into the external jugular vein, while the Occipital vein flows into the suboccipital venous plexus.
Emissary veins connect extracranial veins to intracranial venous sinuses, facilitating potential infection spread.

Lymphatic Drainage of the Scalp

Anterior scalp drains into parotid lymph nodes; posterior scalp drains into mastoid and occipital lymph nodes, which lead to deep cervical lymph nodes.

Clinical Anatomy

Sebaceous Cysts: Result from blocked sebaceous glands and swollen hair follicles.
Loose Areolar Tissue: Known as the dangerous layer; accumulation of blood can cause conditions like a black eye.

Description

This quiz focuses on the blood supply and nerve supply of the face and scalp, including the anatomical details of the facial artery and facial vein. Participants will explore the innervation pattern and consequences of facial nerve injuries. Test your knowledge on the critical components of facial anatomy.