Portal:Cranial nerves
Portal maintenance status: (October 2018)
|
Introduction
Right Juxtaposed skull base with foramina in which many nerves exit the skull.
Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), in contrast to spinal nerves (which emerge from segments of the spinal cord). 10 of the cranial nerves originate in the brainstem. Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck.
Spinal nerves emerge sequentially from the spinal cord with the spinal nerve closest to the head (C1) emerging in the space above the first cervical vertebra. The cranial nerves, however, emerge from the central nervous system above this level. Each cranial nerve is paired and is present on both sides. Depending on definition in humans there are twelve or thirteen cranial nerves pairs, which are assigned Roman numerals I–XII, sometimes also including cranial nerve zero. The numbering of the cranial nerves is based on the order in which they emerge from the brain, front to back (brainstem).
Selected general articles
Transverse section of medulla oblongata below the middle of the olive. ("Nucleus ambiguus" labeled at center right.)
The nucleus ambiguus (literally "ambiguous nucleus") is a group of large motor neurons, situated deep in the medullary reticular formation named by Jacob Clarke. The nucleus ambiguus contains the cell bodies of nerves that innervate the muscles of the soft palate, pharynx, and larynx which are strongly associated with speech and swallowing. As well as motor neurons, the nucleus ambiguus in its "external formation" contains cholinergic preganglionic parasympathetic neurons for the heart.
It is a region of histologically disparate cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla. It receives upper motor neuron innervation directly via the corticobulbar tract. Read more...- The pharyngeal branches of the glossopharyngeal nerve are three or four filaments which unite, opposite the Constrictor pharyngis medius, with the pharyngeal branches of the vagus and sympathetic, to form the pharyngeal plexus.
Branches from this plexus perforate the muscular coat of the pharynx and supply its muscles and mucous membrane. Read more...
Muscles of the neck. Anterior view.
Hyoid bone is white horizontal line near top.
Infrahyoid muscles are below hyoid, while Suprahyoid muscles are labeled above.
The suprahyoid muscles are four muscles located above the hyoid bone in the neck. They are the digastric, stylohyoid, geniohyoid, and mylohyoid muscles. They are all pharyngeal muscles, with the exception of the geniohyoid muscle. The digastric is uniquely named for its two bellies. Its posterior belly rises from the mastoid process of the cranium and slopes downward and forward. The anterior belly arises from the mastoid notch on the inner surface of the mandibular body, which slopes downward and backward. The two bellies connect at the intermediate tendon. The intermediate tendon passes through a connective tissue loop attached to the hyoid bone. The mylohyoid muscles are thin, flat muscles that form a sling inferior to the tongue supporting the floor of the mouth. The geniohyoids are short, narrow muscles that contact each other in the midline. The stylohyoids are long, thin muscles that are nearly parallel with the posterior belly of the digastric muscle. Read more...
The cranial nerve nuclei schematically represented; dorsal view. Motor nuclei in red; sensory in blue.
In the human brainstem, the solitary nucleus (SN) (nucleus of the solitary tract, nucleus solitarius, nucleus tractus solitarii) is a series of purely sensory
nuclei (clusters of nerve cell bodies) forming a vertical column of grey matter embedded in the medulla oblongata. Through the center of the SN runs the solitary tract, a white bundle of nerve fibers, including fibers from the facial, glossopharyngeal and vagus nerves, that innervate the SN. The SN projects to, among other regions, the reticular formation, parasympathetic preganglionic neurons, hypothalamus and thalamus, forming circuits that contribute to autonomic regulation. Cells along the length of the SN are arranged roughly in accordance with function; for instance, cells involved in taste are located in the higher, more anterior ("ventral") part, while those receiving information from cardio-respiratory and gastrointestinal processes are found in the lower, more posterior ("dorsal") part. Read more...- The septal nuclei (medial olfactory area) are a set of structures that lie below the rostrum of the corpus callosum, anterior to the lamina terminalis (the layer of gray matter in the brain connecting the optic chiasma and the anterior commissure where the latter becomes continuous with the rostral lamina). The septal nuclei are composed of medium-size neurons which are classified into medial, lateral, and posterior groups. The septal nuclei receive reciprocal connections from the olfactory bulb, hippocampus, amygdala, hypothalamus, midbrain, habenula, cingulate gyrus, and thalamus.
The septal area (medial olfactory area) has no relation to the sense of smell, but it is considered a pleasure zone in animals.
The septal nuclei play a role in reward and reinforcement along with the nucleus accumbens. In the 1950s, Olds & Milner showed that rats with electrodes implanted in this area will self-stimulate repeatedly (i.e., press a bar to receive electrical current that stimulate the neurons). Experiments on the septal area of humans have taken place since the 1960s. Read more...
The lateral geniculate nucleus (LGN; also called the lateral geniculate body or lateral geniculate complex) is a relay center in the thalamus for the visual pathway. It receives a major sensory input from the retina. The LGN is the main central connection for the optic nerve to the occipital lobe, particularly the primary visual cortex. In humans, each LGN has six layers of neurons (grey matter) alternating with optic fibers (white matter).
The LGN is a small, ovoid, ventral projection at the termination of the optic tract on each side of the brain. The LGN and the medial geniculate nucleus which deals with auditory information are both thalamic nuclei and so are present in both hemispheres. Read more...
Mandibular division of trigeminal nerve, seen from the middle line. The small figure is an enlarged view of the otic ganglion.
The otic ganglion is a small parasympathetic ganglion located immediately below the foramen ovale in the infratemporal fossa and on the medial surface of the mandibular nerve. It is functionally associated with the glossopharyngeal nerve and innervates the parotid gland for salivation.
It is one of four parasympathetic ganglia of the head and neck. The others are the ciliary ganglion, the submandibular ganglion and the pterygopalatine ganglion. Read more...
The maxillary nerve (CN V2) is one of the three branches or divisions of the trigeminal nerve, the fifth (V) cranial nerve. It comprises the principal functions of sensation from the maxillary, nasal cavity, sinuses, the palate and subsequently that of the mid-face, and is intermediate, both in position and size, between the ophthalmic nerve and the mandibular nerve. Read more...
The superior laryngeal nerve is a branch of the vagus nerve. It arises from the middle of the inferior ganglion of vagus nerve and in its course receives a branch from the superior cervical ganglion of the sympathetic nervous system.
All intrinsic laryngeal muscles except the cricothyroids are innervated by the recurrent laryngeal nerve. The cricothyroid muscles are innervated by the superior laryngeal nerve. Read more...
Mandibular division of trigeminal nerve, seen from the middle line. The small figure is an enlarged view of the otic ganglion. (Small petrosal labeled at center top and bottom right.)
The lesser petrosal nerve (also known as the small superficial petrosal nerve) is the general visceral efferent (GVE) component of the glossopharyngeal nerve (CN IX), carrying parasympathetic pre-ganglionic fibers from the tympanic plexus to the parotid gland. It synapses in the otic ganglion, from where the post-ganglionic fibers emerge. Read more...
The inferior salivatory nucleus is one of the components of the glossopharyngeal nerve, which stimulates secretion from the parotid gland.
The inferior salivatory nucleus is a cluster of neurons in the pontine tegmentum (dorsal part of the pons), just above its junction with the medulla. It is the general visceral efferent (GVE) component of the glossopharyngeal nerve supplying the parasympathetic input to the parotid gland for salivation. Read more...
Distribution of the maxillary and mandibular nerves, and the submaxillary ganglion. (Submandibular ganglion visible at bottom left, but not labeled.)
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, and ciliary ganglion). Read more...
Dissection of brainstem. Dorsal view. (Caption for "Vestibular nucleus" is visible at left.)
The vestibular nuclei (VN) are the cranial nuclei for the vestibular nerve.
In Terminologia Anatomica they are grouped in both the pons and the medulla in the brainstem. Read more...
Oblique section through the cavernous sinus.
The ophthalmic nerve (first division of fifth cranial nerve, ophthalmic division of trigeminal nerve, first division of trigeminal nerve, CN V1, latin: nervus ophthalmicus) is the first branch of the trigeminal nerve. The ophthalmic nerve is a sensory nerve mostly carrying general somatic afferent fibers that transmit sensory information to the CNS from structures of the eyeball, the skin of the upper face and anterior scalp, the lining of the upper part of the nasal cavity and air cells, and the meninges of the anterior cranial fossa. Some of ophthalmic nerve branches also convey parasympathetic fibers. Read more...
Transverse section of medulla oblongata below the middle of the olive. ("Nucleus ambiguus" labeled at center right.)
The nucleus ambiguus (literally "ambiguous nucleus") is a group of large motor neurons, situated deep in the medullary reticular formation named by Jacob Clarke. The nucleus ambiguus contains the cell bodies of nerves that innervate the muscles of the soft palate, pharynx, and larynx which are strongly associated with speech and swallowing. As well as motor neurons, the nucleus ambiguus in its "external formation" contains cholinergic preganglionic parasympathetic neurons for the heart.
It is a region of histologically disparate cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla. It receives upper motor neuron innervation directly via the corticobulbar tract. Read more...- The inferior branch of the oculomotor nerve or the inferior division, the larger, divides into three branches.
- One passes beneath the optic nerve to the medial rectus.
- Another, to the inferior rectus.
- The third and longest runs forward between the inferior recti and lateralis to the inferior oblique. From the last a short thick branch is given off to the lower part of the ciliary ganglion, and forms its short root.
All these branches enter the muscles on their ocular surfaces, with the exception of the nerve to the inferior oblique, which enters the muscle at its posterior border. Read more...
The pharyngeal plexus is a network of nerve fibers innervating most of the palate and pharynx. (Larynx, which is innervated by superior and recurrent laryngeal nerve from vagus nerve (CN X), is not included)
It is located on the surface of the middle pharyngeal constrictor muscle. Read more...
The cranial nerve nuclei schematically represented; dorsal view. Motor nuclei in red; sensory in blue.
In the human brainstem, the solitary nucleus (SN) (nucleus of the solitary tract, nucleus solitarius, nucleus tractus solitarii) is a series of purely sensory
nuclei (clusters of nerve cell bodies) forming a vertical column of grey matter embedded in the medulla oblongata. Through the center of the SN runs the solitary tract, a white bundle of nerve fibers, including fibers from the facial, glossopharyngeal and vagus nerves, that innervate the SN. The SN projects to, among other regions, the reticular formation, parasympathetic preganglionic neurons, hypothalamus and thalamus, forming circuits that contribute to autonomic regulation. Cells along the length of the SN are arranged roughly in accordance with function; for instance, cells involved in taste are located in the higher, more anterior ("ventral") part, while those receiving information from cardio-respiratory and gastrointestinal processes are found in the lower, more posterior ("dorsal") part. Read more...
The spinal accessory nucleus lies within the cervical spinal cord (C1-C5) in the posterolateral aspect of the anterior horn. The nucleus ambiguus is classically said to provide the "cranial component" of the accessory nerve.
However, the very existence of this cranial component has been recently questioned and seen as contributing exclusively to the vagus nerve. Read more...
The cranial nerve nuclei schematically represented; dorsal view. Motor nuclei in red; sensory in blue.
In the human brainstem, the solitary nucleus (SN) (nucleus of the solitary tract, nucleus solitarius, nucleus tractus solitarii) is a series of purely sensory
nuclei (clusters of nerve cell bodies) forming a vertical column of grey matter embedded in the medulla oblongata. Through the center of the SN runs the solitary tract, a white bundle of nerve fibers, including fibers from the facial, glossopharyngeal and vagus nerves, that innervate the SN. The SN projects to, among other regions, the reticular formation, parasympathetic preganglionic neurons, hypothalamus and thalamus, forming circuits that contribute to autonomic regulation. Cells along the length of the SN are arranged roughly in accordance with function; for instance, cells involved in taste are located in the higher, more anterior ("ventral") part, while those receiving information from cardio-respiratory and gastrointestinal processes are found in the lower, more posterior ("dorsal") part. Read more...- The superior branch of the oculomotor nerve or the superior division, the smaller, passes medially over the optic nerve. It supplies the superior rectus and levator palpebrae superioris. Read more...
The principal sensory nucleus (or chief sensory nucleus of V) is a group of second order neurons which have cell bodies in the caudal pons.
It receives information about discriminative sensation and light touch of the face as well as conscious proprioception of the jaw via first order neurons of CN V.- Most of the sensory information crosses the midline and travels to the contralateral ventral posteromedial nucleus (VPM) of the thalamus via the anterior trigeminothalamic tract.
- However, information of the oral cavity travels to the ipsilateral VPM of the thalamus via the dorsal trigeminothalamic tract.
The recurrent laryngeal nerve (RLN) is a branch of the vagus nerve (cranial nerve X) that supplies all the intrinsic muscles of the larynx, with the exception of the cricothyroid muscles. There are two recurrent laryngeal nerves, right and left, in the human body. The right and left nerves are not symmetrical, with the left nerve looping under the aortic arch, and the right nerve looping under the right subclavian artery then traveling upwards. They both travel alongside of the trachea. Additionally, the nerves are one of few nerves that follow a recurrent course, moving in the opposite direction to the nerve they branch from, a fact from which they gain their name.
The recurrent laryngeal nerves supply sensation to the larynx below the vocal cords, gives cardiac branches to the deep cardiac plexus, and branches to the trachea, esophagus and the inferior constrictor muscles. The posterior cricoarytenoid muscles, the only muscles that can open the vocal cords, are innervated by this nerve. Read more...
The buccal branches of the facial nerve (infraorbital branches), are of larger size than the rest of the branches, pass horizontally forward to be distributed below the orbit and around the mouth. Read more...
Section through superior colliculus (unlabeled) showing path of oculomotor nerve. ("Edinger–Westphal nucleus" is not on diagram, but would be near oculomotor nuclei.)
The Edinger–Westphal nucleus (accessory oculomotor nucleus) is the parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle.
Alternatively, the Edinger–Westphal nucleus is a term often used to refer to the adjacent population of non-preganglionic neurons that do not project to the ciliary ganglion, but rather project to the spinal cord, dorsal raphe nucleus, lateral septal nuclei, lateral hypothalamic area and the central nucleus of the amygdala, among other regions Read more...
In the tympanic cavity, the tympanic nerve (a branch of CN IX) divides into branches which, along with sympathetic fibres from the carotid plexus, form the tympanic plexus. This plexus is located on the surface of the promontory.
This tympanic plexus gives off:- (1) the lesser petrosal nerve
- (2) the Deep branch (small deep petrosal nerve) to join the greater petrosal nerve
- (3) branches to the tympanic cavity
- Lateral lemniscus in red, as it connects the cochlear nucleus, superior olivary nucleus and the inferior colliculus. Seen from behind.
The lateral lemniscus is a tract of axons in the brainstem that carries information about sound from the cochlear nucleus to various brainstem nuclei and ultimately the contralateral inferior colliculus of the midbrain. Three distinct, primarily inhibitory, cellular groups are located interspersed within these fibers, and are thus named the nuclei of the lateral lemniscus. Read more...
The cranial nerve nuclei schematically represented; dorsal view. Motor nuclei in red; sensory in blue. The olfactory and optic centers are not represented. (Abducens nucleus is VI)
The abducens nucleus is the originating nucleus from which the abducens nerve (VI) emerges—a cranial nerve nucleus. This nucleus is located beneath the fourth ventricle in the caudal portion of the pons, medial to the sulcus limitans.
The abducens nucleus along with the internal genu of the facial nerve make up the facial colliculus, a hump at the caudal end of the medial eminence on the dorsal aspect of the pons. Read more...
The lingual nerve is a branch of the mandibular division of the trigeminal nerve (CN V3), which supplies general sensory innervation (not the gustative one) to the anterior 2/3 of the tongue. It also carries fibers from the facial nerve (CN VII), which carries taste information from the anterior two thirds of the tongue, via the chorda tympani. Read more...
Inner ear illustration showing semicircular canal, hair cells, ampulla, cupula, vestibular nerve, & fluid
The vestibular nerve is one of the two branches of the vestibulocochlear nerve (the cochlear nerve being the other). In humans the vestibular nerve transmits sensory information transmitted by vestibular hair cells located in the two otolith organs (the utricle and the saccule) and the three semicircular canals via the vestibular ganglion. Information from the otolith organs reflects gravity and linear accelerations of the head. Information from the semicircular canals reflects rotational movement of the head. Both are necessary for the sensation of body position and gaze stability in relation to a moving environment.
Axons of the vestibular nerve synapse in the vestibular nucleus are found on the lateral floor and wall of the fourth ventricle in the pons and medulla. Read more...
The trigeminal ganglion (or Gasserian ganglion, or semilunar ganglion, or Gasser's ganglion) is a sensory ganglion of the trigeminal nerve (CN V) that occupies a cavity (Meckel's cave) in the dura mater, covering the trigeminal impression near the apex of the petrous part of the temporal bone. Read more...
Plan of upper portions of glossopharyngeal, vagus, and accessory nerves (auricular labeled at top center)
The auricular branch of the vagus nerve is often termed the Alderman's nerve or Arnold's nerve. The latter name is an eponym for Friedrich Arnold. It supplies sensory innervation to the skin of the ear canal, tragus, and auricle. Read more...
The fibers of the oculomotor nerve arise from a nucleus in the midbrain, which lies in the gray substance of the floor of the cerebral aqueduct and extends in front of the aqueduct for a short distance into the floor of the third ventricle. From this nucleus the fibers pass forward through the tegmentum, the red nucleus, and the medial part of the substantia nigra, forming a series of curves with a lateral convexity, and emerge from the oculomotor sulcus on the medial side of the cerebral peduncle.
The nucleus of the oculomotor nerve does not consist of a continuous column of cells, but is broken up into a number of smaller nuclei, which are arranged in two groups, anterior and posterior. Those of the posterior group are six in number, five of which are symmetrical on the two sides of the middle line, while the sixth is centrally placed and is common to the nerves of both sides. The anterior group consists of two nuclei, an antero-medial and an antero-lateral . Read more...
Need help?
Do you have a question about Cranial nerves that you can't find the answer to?
Consider asking it at the Wikipedia reference desk.
Selected images
The facial nerve passes through the petrous temporal bone, internal auditory meatus, facial canal, stylomastoid foramen, and then the parotid gland.
Left View of the human brain from below, showing origins of cranial nerves.
Right Juxtaposed skull base with foramina in which many nerves exit the skull.Ventral view of the sheep's brain. The exits of the various cranial nerves are marked with red.
Winged scapula may occur due to lesion of the spinal accessory.
Subcategories
- Select [►] to view subcategories
Topics
The cranial nerves | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Terminal |
| ||||||||||||
| Olfactory |
| ||||||||||||
| Optic |
| ||||||||||||
| Oculomotor |
| ||||||||||||
| Trochlear |
| ||||||||||||
| Trigeminal |
| ||||||||||||
| Abducens |
| ||||||||||||
| Facial |
| ||||||||||||
| Vestibulocochlear | |||||||||||||
| Glossopharyngeal |
| ||||||||||||
| Vagus |
| ||||||||||||
| Accessory | |||||||||||||
| Hypoglossal | |||||||||||||
Associated Wikimedia
The following Wikimedia Foundation sister projects provide more on this subject:
Wikibooks
Books
Commons
Media
Wikinews
News
Wikiquote
Quotations
Wikisource
Texts
Wikiversity
Learning resources
Wiktionary
Definitions
Wikidata
Database
- What are portals?
- List of portals
