Nasociliary nerve

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Nerve: Nasociliary nerve
Nerves of the orbit, and the ciliary ganglion. Side view. (Nasociliary is at center.)
Nerves of septum of nose. Right side. (Nasociliary is rightmost yellow line.)
Latin	n. nasociliaris
Gray's	subject #200 888
From	Ophthalmic nerve
To	long root of the ciliary ganglion, the long ciliary nerves, the infratrochlear nerve, and the ethmoidal nerves

The nasociliary nerve is a branch of the ophthalmic nerve. It is intermediate in size between the two other main branches of the ophthalmic nerve, the frontal nerve and the lacrimal nerve, and is more deeply placed.

Path

The nasociliary nerve enters the orbit between the two heads of the lateral rectus muscles and between the superior and inferior rami of the oculomotor nerve (CN III). It passes across the optic nerve (CN II) and runs obliquely beneath the superior rectus muscle and superior oblique muscle to the medial wall of the orbital cavity. After giving the anterior ethmoidal nerve, it terminates as the infratrochlear nerve on the medial margin of the orbit.

Tests

Since the long ciliary nerves carry the afferent limb of the corneal blink reflex, one can test the integrity of the nasociliary nerve (and, ultimately, the trigeminal nerve) by examining this reflex in the patient. Normally both eyes should blink when either conjuntiva is irritated. If neither eye blinks, then either the ipsilateral nasociliary nerve is damaged, or the facial nerve (CN VII, which carries the efferent limb of this reflex) is bilaterally damaged. If only the contralateral eye blinks, then the ipsilateral facial nerve is damaged. If only the ipsilateral eye blinks, then the contralateral facial nerve is damaged.

Branches

The nasociliary nerve gives off the following branches:

• posterior ethmoidal nerve
• long ciliary nerves
• infratrochlear nerve
• communicating branch to the ciliary ganglion (long root of the ciliary ganglion)
• anterior ethmoidal nerve

PLICA is a mnemonic often used to remember these branches.

Additional images

Base of the skull. Upper surface.	Plan of oculomotor nerve.	Nerves of the orbit. Seen from above.	Distribution of the maxillary and mandibular nerves, and the submaxillary ganglion.
The sphenopalatine ganglion and its branches.	Dissection showing origins of right ocular muscles, and nerves entering by the superior orbital fissure.	Pathways in the Ciliary Ganglion.

External links

• SUNY Figs 29:03-08 - "A deeper dissection of the right orbit from a superior approach."
• Norman/Georgetown lesson9 (nasalseptumner)
• Norman/Georgetown cranialnerves (V)
• MedEd at Loyola GrossAnatomy/h_n/cn/cn1/cnb1.htm

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

v • d • e The cranial nerves: trigeminal nerve
ophthalmic (V1)	frontal: supratrochlear - supraorbital (lateral branch, medial branch) nasociliary: long ciliary - infratrochlear - posterior ethmoidal - anterior ethmoidal (external nasal, internal nasal) - sensory root of ciliary ganglion (ciliary ganglion) lacrimal
maxillary (V2)	in meninges middle meningeal in pterygopalatine fossa zygomatic (zygomaticotemporal, zygomaticofacial) - pterygopalatine (pterygopalatine ganglion see below for details) - posterior superior alveolar in infraorbital canal infraorbital nerve: superior alveolar (middle, anterior) - internal nasal branches on face inferior palpebral - external nasal - superior labial (infraorbital plexus)
mandibular (V3)	in meninges meningeal anterior to muscles of mastication (medial pterygoid/to tensor veli palatini, lateral pterygoid, masseteric, deep temporal) - buccal posterior auriculotemporal (otic ganglion) - lingual (submandibular ganglion) - inferior alveolar (mylohyoid, mental)

Acknowledgement and Attribution Regarding Sources of Content

Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .