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 (cranial nerve VIII). It contains the

sensory Sensory may refer to: Biology * Sensory ecology, how organisms obtain information about their environment * Sensory neuron, nerve cell responsible for transmitting information about external stimuli * Sensory perception, the process of acquiri ...

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 enteric nervous system is sometimes considered part o ...

fibers of the facial nerve. Upon reaching the facial canal, it joins with the motor root of the facial nerve at the geniculate ganglion. 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 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. These postganglionic neurons send

axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action ...

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 and after the

nerve to the stapedius muscle The nerve to the stapedius is a branch of the facial nerve (CN VII) which innervates the stapedius muscle. It arises from the CN VII opposite the pyramidal eminence The pyramidal eminence (pyramid) is a conical projection in the middle ear. I ...

has branched off, the facial nerve gives off the chorda tympani nerve. This nerve exits the skull through the Petrotympanic fissure and merges with the lingual nerve, after which it synapses with neurons in the submandibular ganglion. These postganglionic neurons provide parasympathetic innervation to the submandibular and sublingual glands.

Sensory fibers

The sensory component of the intermediate nerve carries input about sensation from the skin of the external auditory meatus, 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 i ...

s of the nasopharynx and

nose A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next pass ...

, and

taste The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste recepto ...

from the anterior two-thirds of the

tongue The tongue is a muscular organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive process, and is the primary organ of taste. The tongue's upper surface (dorsum) is covered by taste bu ...

, 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 s ...

. 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://www.webcitation.org/6I1KtNdi1?url=http://www.neuroanatomy.wisc.edu/virtualbrain/BrainStem/15Salivatory.html {{Authority control Facial nerve