The intermediate nerve, nervus intermedius, nerve of Wrisberg or glossopalatine nerve is the part of the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of ta ...

(cranial nerve VII) located between the motor component of the facial nerve and the

vestibulocochlear nerve The vestibulocochlear nerve or auditory vestibular nerve, also known as the eighth cranial nerve, cranial nerve VIII, or simply CN VIII, is a cranial nerve that transmits sound and equilibrium (balance) information from the inner ear to the br ...

(cranial nerve VIII). It contains the sensory and

parasympathetic The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system. The autonomic nervous system is responsible for regulat ...

fibers of the facial nerve. Upon reaching the

facial canal The facial canal (also known as the Fallopian canal) is a Z-shaped canal in the temporal bone of the skull. It extends between the internal acoustic meatus and stylomastoid foramen. It transmits the facial nerve (CN VII) (after which it is nam ...

, it joins with the motor root of the facial nerve at the

geniculate ganglion The geniculate ganglion (from Latin ''genu'', for "knee") is a bilaterally paired special sense ganglion of the intermediate nerve component of the facial nerve (CN VII). It is situated within facial canal of the head. It contains cell bodies ...

. Alex Alfieri postulates that the intermediate nerve should be considered as a separate cranial nerve and not a part of the facial nerve.

Parasympathetic fibers

The

superior salivatory nucleus The salivatory nuclei are two general visceral efferent fiber, general visceral efferent Nucleus (anatomy), nuclei located in the caudal pons, dorsal and lateral to the facial nucleus. Their neurons give rise to preganglionic nerve fibers, pregan ...

contains the cell bodies of parasympathetic axons within the intermediate nerve. These fibers reach the geniculate ganglion but do not synapse. Some of these preganglionic parasympathetic fibers persist within the greater petrosal nerve as they exit the geniculate ganglion and subsequently synapse with neurons in the

pterygopalatine ganglion The pterygopalatine ganglion (aka Meckel's ganglion, nasal ganglion, or sphenopalatine ganglion) is a parasympathetic ganglion in the pterygopalatine fossa. It is one of four parasympathetic ganglia of the head and neck, (the others being the s ...

. These postganglionic neurons send

axon An axon (from Greek ἄξων ''áxōn'', axis) or nerve fiber (or nerve fibre: see American and British English spelling differences#-re, -er, spelling differences) is a long, slender cellular extensions, projection of a nerve cell, or neuron, ...

s that provide parasympathetic innervation to the

lacrimal gland The lacrimal glands are paired exocrine glands, one for each eye, found in most terrestrial vertebrates and some marine mammals, that secrete the aqueous layer of the tear film. In humans, they are situated in the upper lateral region of each o ...

via a communicating branch from the zygomatic nerve to the lacrimal nerve of cranial nerve V. The remaining preganglionic fibers continue as the mixed facial nerve proper as it extends through the facial canal. Before the nerve exits the skull via the

stylomastoid foramen The stylomastoid foramen is a foramen between the styloid and mastoid processes of the temporal bone of the skull. It is the termination of the facial canal, and transmits the facial nerve, and stylomastoid artery. Facial nerve inflammation in th ...

and after the nerve to the stapedius muscle has branched off, the facial nerve gives off the

chorda tympani nerve Chorda tympani is a branch of the facial nerve that carries gustatory (taste) sensory innervation from the front of the tongue and parasympathetic ( secretomotor) innervation to the submandibular and sublingual salivary glands. Chorda tympani ...

. This nerve exits the skull through the

petrotympanic fissure The petrotympanic fissure (also known as the squamotympanic fissure or the glaserian fissure) is a fissure in the temporal bone that runs from the temporomandibular joint to the tympanic cavity. The mandibular fossa is bounded, in front, by the ...

and merges with the

lingual nerve The lingual nerve carries sensory innervation from the anterior two-thirds of the tongue. It contains fibres from both the mandibular division of the trigeminal nerve (CN V) and from the facial nerve (CN VII). The fibres from the trigeminal nerve ...

, after which it synapses with neurons in the

submandibular ganglion The submandibular ganglion (or submaxillary ganglion in older texts) is part of the human autonomic nervous system. It is one of four parasympathetic ganglia of the head and neck. (The others are the otic ganglion, pterygopalatine ganglion, an ...

. These postganglionic neurons provide parasympathetic innervation to the submandibular and

sublingual gland The sublingual gland (''glandula sublingualis'') is a seromucous polystomatic exocrine gland. Located underneath the oral diaphragm (''diaphragma oris''), the sublingual gland is the smallest and most diffuse of the three major salivary glands of ...

Sensory fibers

The sensory component of the intermediate nerve carries input about sensation from the skin of the

external auditory meatus The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the auricle to the eardrum and is about in length and in diameter. Str ...

, from the

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...

s of the

nasopharynx The pharynx (: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates, though its ...

and

nose A nose is a sensory organ and respiratory structure in vertebrates. It consists of a nasal cavity inside the head, and an external nose on the face. The external nose houses the nostrils, or nares, a pair of tubes providing airflow through the ...

, and

taste The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste. Taste is the perception stimulated when a substance in the mouth biochemistry, reacts chemically with taste receptor cells l ...

from the anterior two-thirds of the

tongue The tongue is a Muscle, muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for chewing and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper s ...

, floor of the mouth, and the soft

palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sep ...

. The sensory information from the

s of the nasopharynx and palate is carried along the greater petrosal nerve, while the chorda tympani nerve (and lingual nerve) carries taste input from the anterior two-thirds of the tongue, floor of mouth, and soft palate. The geniculate ganglion contains the cell bodies of the sensory component of the nervus intermedius. Nervus intermedius neuralgia is a pain syndrome associated with the nervus intermedius.

References

External links

* * https://web.archive.org/web/20130930044559/http://www.neuroanatomy.wisc.edu/virtualbrain/BrainStem/15Salivatory.html {{Authority control Facial nerve Cranial nerves