Anatomy Lecture: The Trigeminal Nerve

Jul 12, 2024

Anatomy Lecture: The Trigeminal Nerve (CN V)

Introduction

  • Presenter: Dr. Mohammed Khan
  • Topic: Trigeminal Nerve (Cranial Nerve V)
  • Translation: Dr. Anhar S. Al-Ahdal

Overview

  • Importance: Vital for dentists, both sensory and motor functions.
  • Anatomy: Divides into three main parts: Ophthalmic (V1), Maxillary (V2), Mandibular (V3).

Divisions of the Trigeminal Nerve

1. Ophthalmic Division (V1)

  • Type: Sensory only.
  • Functions: Supplies sensation to the scalp, eyes, and forehead.
  • Pathways: Passes lateral to the cavernous sinus and exits via the superior orbital fissure.
  • Key Branches:
    • Lacrimal Nerve: Nourishes lacrimal gland and upper eyelid.
    • Frontal Nerve: Divides into supra-trochlear and supra-orbital nerves, nourishing the scalp and forehead.
    • Nasociliary Nerve: Divides into posterior ethmoidal, anterior ethmoidal, infra-trochlear, and long ciliary nerves.

2. Maxillary Division (V2)

  • Type: Sensory only.
  • Functions: Sensation to mid-face including upper teeth, cheek, lateral nose, lower eyelid, and upper lip.
  • Pathways: Passes through foramen rotundum, pterygopalatine fossa, and inferior orbital fissure.
  • Key Branches:
    • Zygomatic Branch: Divides into zygomaticofacial and zygomaticotemporal nerves.
    • Infra-orbital Nerve: Divides into inferior palpebral, lateral nasal, and superior labial nerves. Also gives anterior and middle superior alveolar nerves.
    • Posterior Superior Alveolar Nerve: Supplies sensation to back upper teeth and maxillary sinus.
    • Pterygopalatine Ganglion: Gives branches like greater palatine, lesser palatine, and nasopalatine nerves.

3. Mandibular Division (V3)

  • Type: Mixed (motor and sensory).
  • Functions: Supplies sensation to lower face and motor functions to mastication muscles.
  • Pathways: Passes through foramen ovale.
  • Motor Branches:
    • Masseter, Temporalis, Medial pterygoid, Lateral pterygoid, Tensor veli palatini, Tensor tympani.
  • Sensory Branches:
    • Long Buccal Nerve: Supplies buccal gingiva of posterior teeth.
    • Auriculotemporal Nerve: Sensation to ear and temporal region.
    • Inferior Alveolar Nerve: Passes through mandibular foramen, supplies lower teeth and chin (via mental nerve).
    • Lingual Nerve: Sensation to anterior 2/3 of tongue and lingual gingiva.
    • Mylohyoid Nerve: Motor supply to mylohyoid muscle and anterior belly of digastric muscle.

Clinical Relevance

  • Assessment of nerve damage.
  • Important questions may cover specific pathways and branches.

Conclusion

  • Summary: Detailed exploration of trigeminal nerve divisions and their anatomical pathways.
  • Next Steps: Review nerve pathways and branches, and their clinical relevance.

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