Basic Anatomy
What are the three main divisions of the trigeminal nerve?
Ophthalmic (V1), Maxillary (V2), Mandibular (V3)
Is the trigeminal nerve sensory, motor, or mixed?
Mixed (mostly sensory, motor only in V3)
Name of the main sensory ganglion?
Trigeminal (semilunar / Gasserian) ganglion
Severe sudden facial pain along V2 or V3?
Trigeminal neuralgia
Which CN gives the efferent limb of the corneal reflex?
Facial nerve (CN VII)
Which division contains both sensory and motor fibers?
Mandibular division (V3)
Which muscles are innervated by V3 motor fibers?
Muscles of mastication (masseter, temporalis, medial/lateral pterygoid)
It sits in which dural pouch?
Meckel’s cave
Which division is affected by a maxillary sinus tumor?
V2
Which nerve carries parasympathetic fibers to the lacrimal gland via CN V pathways?
Greater petrosal nerve (CN VII → via zygomatic → lacrimal branch of V1)
Which skull opening does V1 pass through?
Superior orbital fissure
Which sensory modality uses the mesencephalic nucleus?
Proprioception
Which divisions arise from the trigeminal ganglion?
V1, V2, V3 (all three)
No sensation on forehead — which division?
V1
How is CN V involved in headaches?
Trigeminovascular activation releases CGRP → pain from meninges
Which nucleus receives pain & temperature from CN V?
Spinal trigeminal nucleus
How does CN V contribute to the jaw-jerk reflex?
V3 is both afferent and efferent limb
What type of neurons does it contain?
Pseudounipolar sensory neurons
How can cavernous sinus lesions affect CN V?
They compress V1/V2, causing sensory loss in their dermatomes
Where do trigeminal sensory fibers synapse in the thalamus?
Ventral posteromedial nucleus (VPM)
Damage to which division affects the corneal reflex, and why?
V1 (nasociliary branch) — it carries the afferent limb of the reflex
Why is trigeminal proprioception unique?
Primary sensory neuron cell bodies are in the mesencephalic nucleus, not a peripheral ganglion
How does infection cause trigeminal zoster?
Varicella-zoster virus stays latent in the ganglion and reactivates along dermatomes
Why does microvascular decompression help trigeminal neuralgia?
It relieves compression of CN V root by the superior cerebellar artery
Tumor compresses trigeminal ganglion + internal carotid artery — combined symptoms?
• Facial sensory loss (CN V)
• Partial Horner syndrome (due to sympathetic fiber compression)