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High-Yield Concepts in Head and Neck Anatomy

Nov 28, 2024

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Quick Revision Series: Lecture 4

Introduction

  • Focus on high-yield topics based on recent exam patterns.
  • Key topics in the head, neck, and face: parasympathetic ganglia, muscles of mastication, cavernous sinus, deep cervical fascia, great auricular nerve, cranial nerve columns.

Head, Neck, and Face

Cranial Nerve Columns

  • Important Nerves: 7th, 9th, and 10th nerves.
    • Columns not related: GSE (General Somatic Efferent) and SSA (Special Somatic Afferent).
    • GSE: Related to extraocular and tongue muscles, supplied by CN 3, 4, 6, and 12.
    • SSA: Related to CN 1, 2, and 8.
  • Trigeminal Nerve (CN 5)
    • Columns: SVE (Special Visceral Efferent) and GSA (General Somatic Afferent).
    • Supplies muscles of mastication.

Parasympathetic Ganglia

  • Four Main Ganglia: Ciliary, Pterygopalatine, Otic, and Submandibular.
  • Secretomotor Pathways:
    • Lacrimal Gland: Superior Salivatory Nucleus → Facial Nerve → Greater Petrosal Nerve → Pterygopalatine Ganglion → Maxillary/Ophthalmic Nerve → Lacrimal Gland.
    • Submandibular/Sublingual Glands: Facial Nerve → Chorda Tympani → Lingual Nerve → Submandibular Ganglion.
    • Parotid Gland: Inferior Salivatory Nucleus → Glossopharyngeal Nerve → Jacobson's Nerve → Tympanic Plexus → Lesser Petrosal Nerve → Otic Ganglion → Auriculotemporal Nerve.

Relations of Ganglia

  • Ciliary Ganglion: Between optic nerve and lateral rectus.
  • Submandibular Ganglion: Superficial to hyoglossus muscle, below lingual nerve, above submandibular duct.
  • Otic Ganglion: Medial to mandibular nerve, anterior to medial pterygoid muscle, posterior to foramen spinosum.

Deep Cervical Fascia

  • Layers: Investing, Pretracheal, Prevertebral.
  • Carotid Sheath: Contains common/internal carotid artery, internal jugular vein, vagus nerve.
    • Anterior relation: Ansa cervicalis
    • Posterior relation: Sympathetic chain
    • Associated nerves: Phrenic (in front of anterior scalene), roots of brachial plexus (between anterior and medial scalene).

Cavernous Sinus

Relations

  • Lateral Wall: CN 3, 4, ophthalmic nerve, uncus.
  • Medial: Pituitary gland, sphenoid body.
  • Floor: Foramen lacerum.
  • Contents: Internal carotid artery, CN 6 (abducent nerve).

Channels

  • Incoming: Superficial middle cerebral vein, inferior cerebral vein, superior/inferior ophthalmic veins, sphenoparietal sinus, middle meningeal sinus.
  • Outgoing: Superior petrosal sinus (to transverse sinus), inferior petrosal sinus (to sigmoid sinus).
  • Emissary Vein: Superior ophthalmic vein (both incoming and outgoing).

Muscles of Mastication

  • Temporalis: Elevation and retraction.
  • Masseter: Elevation.
  • Medial Pterygoid: Elevation.
  • Lateral Pterygoid: Protraction and depression.

Orbit and Laryngeal Muscles

  • Extraocular Muscles: Superior oblique (CN 4), Lateral rectus (CN 6), Others (CN 3).
  • Laryngeal Muscles: Posterior cricoarytenoid, lateral cricoarytenoid (adductor), thyroarytenoid (relaxer), thyroepiglotticus (opens inlet), aryepiglotticus (closes inlet).

These notes cover the key points discussed in the lecture, offering a condensed reference for quick review and examination preparation.

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