Anatomy & Histology · single question
A patient has tearing (lacrimation) — which nerve innervates the affected structure?
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Correct answer: A. Zygomatic branch of CN VII
Zygomatic branch of CN VII (A) — specifically, the postganglionic parasympathetic fibers that travel with the zygomatic nerve (branch of V2) to the lacrimal gland. The pathway:
1. Preganglionic parasympathetic fibers from the facial nerve (CN VII) → greater petrosal nerve → pterygopalatine ganglion (synapse)
2. Postganglionic fibers → join zygomatic nerve (V2) → lacrimal nerve (V1) → lacrimal gland
• The lacrimal nerve (V1) provides SENSORY innervation to the lacrimal gland region but does NOT control secretion.
• Tearing/lacrimation is a SECRETORY function controlled by parasympathetics from CN VII via the zygomatic branch pathway.
• Damage to CN VII (Bell's palsy) can impair lacrimation and put the cornea at risk.
1. Preganglionic parasympathetic fibers from the facial nerve (CN VII) → greater petrosal nerve → pterygopalatine ganglion (synapse)
2. Postganglionic fibers → join zygomatic nerve (V2) → lacrimal nerve (V1) → lacrimal gland
• The lacrimal nerve (V1) provides SENSORY innervation to the lacrimal gland region but does NOT control secretion.
• Tearing/lacrimation is a SECRETORY function controlled by parasympathetics from CN VII via the zygomatic branch pathway.
• Damage to CN VII (Bell's palsy) can impair lacrimation and put the cornea at risk.
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