Nerves of the Orbit

 These are:

1. Optic, 

2. Oculomotor with ciliary ganglion,

3. Trochlear,

4. Branches of ophthalmic and maxillary divisions of the trigeminal,

5. Abducent, and

6. Sympathetic nerves

CILIARY GANGLION

Ciliary ganglion is a peripheral parasympathetic ganglion placed in the course of the oculomotor nerve.

It lies near the apex of the orbit between the optic nerve and the tendon of the lateral rectus muscle. 

It has parasympathetic, sensory and sympathetic roots.

The parasympathetic root arises from the nerve to the inferior oblique. 

It contains preganglionic fibres that begin in the Edinger-Westphal nucleus. 

The fibres relay in the ciliary ganglion. 

Postganglionic fibres arising in the ganglion pass through the short ciliary nerves and supply the 

sphincter pupillae and the ciliaris muscle 

These intraocular muscles are used in accommodation.

The sensory root comes from the nasociliary nerve. 

It contains sensory fibres for the eyeball. 

The fibres do not relay in the ganglion.

The sympathetic root is a branch from the internal carotid plexus. 

It contains postganglionic fibres arising in the superior cervical ganglion (preganglionic fibres

reach the ganglion from lateral horn of T1 spinal segment) which pass along internal carotid, ophthalmic and long ciliary arteries.  

They pass out of the ciliary ganglion without relay in the short ciliary nerves to supply the blood vessels of the eyeball. 

They also supply the dilator pupillae.

Branches:

• The ganglion gives off 8 to 10 short ciliary nerves 
• which divide into 15 to 20 branches, and 
• then pierce the sclera around the entrance of the optic nerve. 
• They contain fibres from all the three roots of the ganglion.

Lacrimal Nerve

This is the smallest of the three terminal branches of ophthalmic nerve. 

It enters the orbit through lateral part of superior orbital fissure and 

runs forwards along the upper border of lateral rectus muscle, in company with lacrimal artery. 

Anteriorly, it receives communication from zygomaticotemporal nerve, passes deep to the 

lacrimal gland, and ends in the lateral part of the upper eyelid.

The lacrimal nerve supplies the lacrimal gland, the conjunctiva and the upper eyelid. 

Its own fibres to the gland are sensory. 

The secretomotor fibres to the gland come from the greater petrosal nerve through its communication with the zygomaticotemporal nerve

Frontal Nerve

This is the largest of the three terminal branches of the ophthalmic nerve. 

It begins in the lateral wall of the anterior part of the cavernous sinus.

It enters the orbit through the lateral part of the superior orbital fissure, and 

runs forwards on the superior surface of the levator palpebrae superioris. 

At the middle of the orbit, it divides into a small supratrochlear branch and a large supraorbital branch.

The supratrochlear nerve emerges from the orbit above the trochlea about one finger breadth from the median plane. 

It supplies the conjunctiva, the upper eyelid, and a small area of the skin of the forehead above the root

of the nose.

The supraorbital nerve emerges from the orbit through the supraorbital notch or foramen about two fingers

breadth from the median plane. 

It divides into medial and lateral branches which runs upwards over the forehead and scalp. 

It supplies the conjunctiva, the central part of the upper eyelid, the frontal air sinus and the skin of the forehead and scalp up to the vertex, or even up to the lambdoid suture.

Nasociliary Nerve

• This is one of the terminal branches of the ophthalmic division of the trigeminal nerve

• It begins in the lateral wall of the anterior part of the cavernous sinus.

• It enters the orbit through the middle part of the superior orbital fissure between the two divisions of the oculomotor nerve

• It crosses above the optic nerve from lateral to medial side along with ophthalmic artery and runs along the medial wall of the orbit between the superior oblique and the medial rectus.

• It ends at the anterior ethmoidal foramen by dividing into the infratrochlear and anterior ethmoidal nerves 

Its branches are as follows.

1. A communicating branch to the ciliary ganglion forms the sensory root of the ganglion. 

It is often mixed with the sympathetic root 

2. Two or three long ciliary nerves run on the medial side of the optic nerve, pierce the sclera, and supply sensory nerves to the cornea, the iris and the ciliary body. 

They also carry sympathetic nerves to the dilator pupillae.

3. The posterior ethmoidal nerve passes through the posterior ethmoidal foramen and supplies the ethmoidal and sphenoidal air sinuses.

4. The infratrochlear nerve is the smaller terminal branch of the nasociliary nerve given off at the anterior ethmoidal foramen.

It emerges from the orbit below the trochlea for the tendon of the superior oblique and appears on the face above the medial angle of the eye.

• It supplies the conjunctiva, the lacrimal sac and caruncle, the medial ends of the eyelids and the upper half of the external nose.

5. The anterior ethmoidal nerve is the larger terminal branch of the nasociliary nerve.

• It leaves the orbit by passing through the anterior ethmoidal foramen.

• It appears, for a very short distance, in the anterior cranial fossa, above the cribriform plate of the ethmoid bone.

• It then descends into the nose through a slit at the side of the anterior part of the crista galli.

• In the nasal cavity, it lies deep to the nasal bone.

• It gives off two internal nasal branches, medial and lateral to the mucosa of the nose.

• Finally, it emerges at the lower border of the nasal bone as the external nasal nerve which supplies the skin of the lower half of the nose. 

Infraorbital Nerve

It is the continuation of the maxillary nerve. 

It enters the orbit through the inferior orbital fissure.  

It then runs forwards on the floor of the orbit or the roof of the maxillary sinus, at first in the infraorbital groove and then in the infraorbital canal remaining outside the periosteum of the 

orbit. 

It emerges on the face through the infraorbital foramen and 

terminates by dividing into palpebral, nasal and labial branches 

The nerve is accompanied by the infraorbital branch of the third part of the maxillary artery and the accompanying vein.

Branches

1. The middle superior alveolar nerve arises in the infraorbital groove, runs in the lateral wall of the

maxillary sinus, and supplies the upper premolar teeth.

2. The anterior superior alveolar nerve arises in the infraorbital canal, and runs in a sinuous canal having a 

complicated course in the anterior wall of the maxillary sinus.  

It supplies the upper incisor and canine teeth, the maxillary sinus, and the anteroinferior part of the nasal cavity where it communicates with branches of anterior ethmoidal

and anterior palatine nerves.

3. Terminal branches palpebral, nasal and labial supply a large area of skin on the face. 

They also supply the mucous membrane of the upper lip and cheek

ZYGOMATIC NERVE

It is a branch of the maxillary nerve, given off in the pterygopalatine fossa. 

It enters the orbit through the lateral end of the inferior orbital fissure, and runs along the lateral 

wall, outside the periosteum, to enter the zygomatic bone. 

just before or after entering the bone it divides into its two terminal branches, 

the zygomaticofacial and zygomaticotemporal nerves which supply the skin of the face and of 

the anterior part of the temple. 

The communicating branch to the lacrimal nerve, which contains secretomotor fibres to the 

lacrimal gland, arises from the zygomaticotemporal nerve, and runs in the 

lateral wall of the orbit

SYMPATHETIC NERVES OF THE ORBIT

Sympathetic nerves arise from the internal carotid plexus and enter the orbit through the following sources.

1. The dilator pupillae of the iris is supplied by sympathetic nerves that pass through the ophthalmic

nerve, the nasociliary nerve, and its long ciliary branches.

2 Other sympathetic nerves enter the orbit as follows:

a. A plexus surrounds the ophthalmic artery.

b. A direct branch from the internal carotid plexus passes through the superior orbital fissure and

joins the ciliary ganglion.

c. Other filaments pass along the oculomotor, trochlear, abducent, and ophthalmic nerves. 

All these sympathetic nerves are vasomotor in function.

Watch the lectures on YouTube:

Ciliary ganglion | Situation | Relations | Connections | Branches & Distribution

Branches of Ophthalmic Nerve - Lacrimal, Frontal & Nasociliary Nerves & Sympathethic Nerves of Orbit