Great petrosal nerve
Encyclopedia
The greater petrosal nerve is a nerve
in the skull that branches from the facial nerve
; it forms part of a chain of nerves that innervates the lacrimal gland
. The fibres have synapses in the pterygopalatine ganglion
.
that arises from the geniculate ganglion
, a part of the facial nerve inside the facial canal
. It enters the middle cranial fossa
through the hiatus for the greater (superficial) petrosal nerve (on the anterior surface of the petrous temporal bone). It proceeds towards the foramen lacerum
, where it joins the deep petrosal nerve
(sympathetic) to form the nerve of the pterygoid canal. The nerve of the pterygoid canal passes through the pterygoid canal
to reach the pterygopalatine ganglion
.
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...
in the skull that branches from 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...
; it forms part of a chain of nerves that innervates 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...
. The fibres have synapses in the pterygopalatine ganglion
Pterygopalatine ganglion
The pterygopalatine ganglion is a parasympathetic ganglion found in the pterygopalatine fossa. It is one of four parasympathetic ganglia of the head and neck....
.
Structure
The greater (superficial) petrosal nerve is a branch of the facial nerveFacial 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...
that arises from the geniculate ganglion
Geniculate ganglion
The geniculate ganglion is an L-shaped collection of fibers and sensory neurons of the facial nerve located in the facial canal of the head...
, a part of the facial nerve inside the facial canal
Facial canal
The facial canal is a Z-shaped canal running through the temporal bone from the internal acoustic meatus to the stylomastoid foramen. In humans it is approximately 3 centimeters long, which makes it the longest human osseous canal of a nerve...
. It enters the middle cranial fossa
Middle cranial fossa
The middle fossa, deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull. It is separated from the posterior fossa by the clivus and the petrous crest....
through the hiatus for the greater (superficial) petrosal nerve (on the anterior surface of the petrous temporal bone). It proceeds towards the foramen lacerum
Foramen lacerum
The foramen lacerum is a triangular hole in the base of the skull located at the base of the medial pterygoid plate.-Transit through the foramen lacerum:...
, where it joins the deep petrosal nerve
Deep petrosal nerve
The deep petrosal nerve is given off from the carotid plexus, and runs through the carotid canal lateral to the internal carotid artery....
(sympathetic) to form the nerve of the pterygoid canal. The nerve of the pterygoid canal passes through the pterygoid canal
Pterygoid canal
The pterygoid canal is a passage in the skull leading from just anterior to the foramen lacerum in the middle cranial fossa to the pterygopalatine fossa.-Structure:...
to reach the pterygopalatine ganglion
Pterygopalatine ganglion
The pterygopalatine ganglion is a parasympathetic ganglion found in the pterygopalatine fossa. It is one of four parasympathetic ganglia of the head and neck....
.