Lacrimal nerve
Encyclopedia
The lacrimal nerve is the smallest of the three branches of the ophthalmic division of the trigeminal nerve
.
It sometimes receives a filament from the trochlear nerve
, but this is possibly derived from the branch that goes from the ophthalmic to the trochlear nerve
.
It passes forward in a separate tube of dura mater
, and enters the orbit through the narrowest part of the superior orbital fissure.
In the orbit it runs along the upper border of the lateral rectus
, with the lacrimal artery
, and communicates with the zygomatic branch of the maxillary nerve.
It enters the lacrimal gland
and gives off several filaments, which supply sensory innervation to the gland and the conjunctiva
.
Then, it pierces the orbital septum
, and ends in the skin of the upper eyelid
, joining with filaments of the facial nerve
.
The lacrimal nerve is occasionally absent, and its place is then taken by the zygomaticotemporal branch of the maxillary nerve. Sometimes the latter branch is absent, and a continuation of the lacrimal nerve is substituted for it.
, conjunctiva
, and the lateral upper eyelids.
The zygomatic nerve carries sensory fibers from the skin and mucous membranes. It also carries post-synaptic parasympathetic fibers (originating in the pterygopalatine ganglion) to the lacrimal nerve via a communication. These fibers will eventually provide innervation to the lacrimal gland.
Trigeminal nerve
The trigeminal nerve contains both sensory and motor fibres. It is responsible for sensation in the face and certain motor functions such as biting, chewing, and swallowing. Sensory information from the face and body is processed by parallel pathways in the central nervous system...
.
It sometimes receives a filament from the trochlear nerve
Trochlear nerve
The trochlear nerve is a motor nerve that innervates a single muscle: the superior oblique muscle of the eye....
, but this is possibly derived from the branch that goes from the ophthalmic to the trochlear nerve
Trochlear nerve
The trochlear nerve is a motor nerve that innervates a single muscle: the superior oblique muscle of the eye....
.
It passes forward in a separate tube of dura mater
Dura mater
The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. It is derived from Mesoderm. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for...
, and enters the orbit through the narrowest part of the superior orbital fissure.
In the orbit it runs along the upper border of the lateral rectus
Lateral rectus muscle
The lateral rectus muscle is a muscle in the orbit. It is one of six extraocular muscles that control the movements of the eye and the only muscle innervated by the abducens nerve, cranial nerve VI....
, with the lacrimal artery
Lacrimal artery
The lacrimal artery arises close to the optic foramen, and is one of the largest branches derived from the ophthalmic artery: not infrequently it is given off before the artery enters the orbit....
, and communicates with the zygomatic branch of the maxillary nerve.
It enters the lacrimal gland
Lacrimal gland
The lacrimal glands are paired almond-shaped glands, one for each eye, that secrete the aqueous layer of the tear film. They are situated in the upper, outer portion of each orbit, in the lacrimal fossa of the orbit formed by the frontal bone. Inflammation of the lacrimal glands is called...
and gives off several filaments, which supply sensory innervation to the gland and the conjunctiva
Conjunctiva
The conjunctiva covers the sclera and lines the inside of the eyelids. It is composed of rare stratified columnar epithelium.-Function:...
.
Then, it pierces the orbital septum
Orbital septum
The orbital septum is a membranous sheet that acts as the anterior boundary of the orbit. It extends from the orbital rims to the eyelids...
, and ends in the skin of the upper eyelid
Eyelid
An eyelid is a thin fold of skin that covers and protects an eye. With the exception of the prepuce and the labia minora, it has the thinnest skin of the whole body. The levator palpebrae superioris muscle retracts the eyelid to "open" the eye. This can be either voluntarily or involuntarily...
, joining with filaments of the facial nerve
Facial nerve
The facial nerve is the seventh of twelve paired cranial nerves. It emerges from the brainstem between the pons and the medulla, and controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity...
.
The lacrimal nerve is occasionally absent, and its place is then taken by the zygomaticotemporal branch of the maxillary nerve. Sometimes the latter branch is absent, and a continuation of the lacrimal nerve is substituted for it.
Functions
It provides sensory innervations for the lacrimal glandLacrimal gland
The lacrimal glands are paired almond-shaped glands, one for each eye, that secrete the aqueous layer of the tear film. They are situated in the upper, outer portion of each orbit, in the lacrimal fossa of the orbit formed by the frontal bone. Inflammation of the lacrimal glands is called...
, conjunctiva
Conjunctiva
The conjunctiva covers the sclera and lines the inside of the eyelids. It is composed of rare stratified columnar epithelium.-Function:...
, and the lateral upper eyelids.
The zygomatic nerve carries sensory fibers from the skin and mucous membranes. It also carries post-synaptic parasympathetic fibers (originating in the pterygopalatine ganglion) to the lacrimal nerve via a communication. These fibers will eventually provide innervation to the lacrimal gland.