• Oculomotor nerve & divisions
• Ciliary ganglion
• Ophthalmic nerve
• Maxillary nerve
• Infraorbital nerve
Category 2
• Branches of ophthalmic nerve
• Zygomatic branches of maxillary nerve
Category 3
Nil
Oculomotor Nerve & Divisions |
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| CATEGORY 1PENDING |
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Ciliary Ganglion |
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| CATEGORY 1PENDING |
The ciliary ganglion contains the synapses of the preganglionic parasympathetic fibres from the Edinger-Westphal nucleus and provides the postganglionic neurons for the pupillary sphincter and ciliary body.
Location
It lies between the optic nerve and lateral rectus muscle in the posterior orbit, behind the eye.
Supply
The neurons supply:
- Pupillary sphincter muscle
- Constricts the pupil
- Comprises 95% of the neurons in the ciliary ganglion
- Ciliary muscle
- Contracts to make the lens more convex
Branches
- Short ciliary nerves
- Course forward together with the ciliary arteries and accompanied by the long ciliary nerves from the nasociliary
- Supply the ciliaris muscle, iris and cornea
- Supplies pre-ganglionic parasympathetic fibres to the ciliary ganglion, which innervates the sphincter pupillae and ciliary muscles
Ophthalmic Nerve |
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| CATEGORY 1PENDING |
The ophthalmic nerve is a terminal branch of the trigeminal nerve.
Nuclei
Sensory nuclei (3): mesencephalic nucleus, principal sensory nucleus, spinal nucleus
Motor nucleus (1): motor nucleus of the trigeminal nerve
Course
At the level of the pons, the sensory nuclei merge to form a large sensory root.
The motor nucleus continues to form a separate motor root.
Within the middle cranial fossa, the sensory root expands into the trigeminal ganglion.
The trigeminal ganglion is located lateral to the cavernous sinus, in a depression of the temporal bone known as the trigeminal cave or Meckel’s cave.
The motor root passes inferiorly to the sensory root, along the floor of the trigeminal cave. Motor fibres are only distributed to the mandibular division (V3).
From the trigeminal ganglion, the three terminal divisions of the trigeminal nerve arise; the ophthalmic (V1), maxillary (V2) and mandibular (V3) nerves.
Course
- Arises from the anterior edge of the trigeminal ganglion
- Extends forward through the lateral wall of the dura mater of the cavernous sinus
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After leaving the cavernous sinus, the ophthalmic nerve exits the cranium via the superior orbital fissure, where divides into its three terminal branches
Branches
- Lacrimal nerve
- Frontal nerve
- Nasociliary nerve
Relations
- Superiorly – trochlear nerve
- Inferolaterally – maxillary nerve
- Medially – Medial to all of these three nerves is located the internal carotid artery that goes through the cavernous sinus
These three branches provide sensory innervation to the skin and mucous membranes of the structures derived from the frontonasal prominence.
Sensory Function
- The eyes
- Conjunctiva and orbital contents including the lacrimal gland
- Nasal cavity, frontal sinus, ethmoidal cells
- Falx cerebri
- Dura mater of the anterior cranial fossa
- Superior parts of the tentorium cerebelli
- Upper eyelid
- Dorsum of the nose
- Anterior part of the scalp
- Forehead and scalp
- Frontal, ethmoid and sphenoid sinuses
- Upper eyelid and its conjunctiva
- Cornea
- Dorsum of the nose
- Lacrimal gland
- Parts of the meninges and tentorium cerebelli (recurrent tentorial branch)
The table below outlines the structures innervated by branches of CNV1.
| Nerve | Branches | Innervation |
| Frontal (largest of three terminal branches of CNV1) | Supraorbital | Upper eyelid and conjunctiva
Scalp |
| Supratrochlear | Upper eyelid and conjunctiva
Forehead |
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| Lacrimal (smallest of three terminal branches of CNV1) | Receives branch from zygomatic nerve of CNV2 containing parasympathetic fibres | Sensory innervation of lacrimal gland, upper eyelid and conjunctiva
Contains parasympathetic fibres to lacrimal gland. |
| Nasociliary | Anterior ethmoid nerve | Sensory innervation of mucous membranes of frontal, ethmoid and sphenoid sinuses.
Nasal cavity |
| Posterior ethmoid nerve | Absent in approximately 30% of people
Sensory innervation to mucous membranes of sphenoid sinus |
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| Infratrochlear nerve | Bridge of nose Upper eyelid and conjunctiva | |
| Long ciliary nerves | Sensory innervation to eye (cornea, ciliary bodies, iris)
Contains sympathetic fibres to dilator pupillae muscle. |
The ophthalmic nerve itself does not contain any autonomic fibres. However, nerves from the sympathetic and parasympathetic system ‘hitchhike’ on CNV1:
- Sympathetic fibres (from the superior cervical ganglion) hitchhike on branches of the nasociliary nerve (long ciliary nerves) to reach the dilator pupillae in the eye.
- Parasympathetic fibres (from the pterygopalatine ganglion) hitchhike along the zygomatic branch of the maxillary nerve (CNV2) and then the lacrimal branch of the ophthalmic nerve (CNV1) to reach the lacrimal gland. The lacrimal branch itself provides sensory innervation to the lacrimal gland.