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Encyclopedia > Facial motor nucleus
Brain: Facial motor nucleus
Plan of the facial and intermediate nerves and their communication with other nerves. ("Nucleus of Facial N." labeled at upper left.)
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Latin n. nervi facialis
Gray's subject #
Part of
Components
Artery
Vein
Acronym(s)
NeuroNames hier-581
MeSH [1]
Dorlands/Elsevier n_11/12581950

The facial motor nucleus is a collection of neurons in the brainstem that belong to the facial nerve (cranial nerve VII). These lower motor neurons innervate the muscles of facial expression and the stapedius. Latin is an ancient Indo-European language originally spoken in the region around Rome called Latium. ... NeuroNames is a system of nomenclature for the brain and related structures. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Elseviers logo Elsevier, the worlds largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. ... Drawing by Santiago Ramón y Cajal of cells in the pigeon cerebellum. ... The brain stem is the stalk of the brain below the cerebral hemispheres. ... The facial nerve is seventh of twelve paired cranial nerves. ... Cranial nerves are nerves which start directly from the brainstem instead of the spinal cord. ... Lower motor neurons (LMNs) are the motoneurons connecting the brainstem and spinal cord to muscle fibers, bringing the nerve impulses from the upper motor neurons out to the muscles. ... The stapedius is the smallest striated muscle in the human body. ...

Contents


Anatomy

The nucleus is situated in the caudal portion of the ventrolateral pontine tegmentum. Its axons take an unusual course, traveling dorsally and looping around the abducens nucleus, then traveling ventrally to exit the ventral pons medial to the spinal trigeminal nucleus. These axons form the motor component of the facial nerve, with parasympathetic and sensory components forming the nervus intermedius. Position of the pons in the human brain The pons (sometimes pons Varolii after Costanzo Varolio) is a knob on the brain stem. ... The abducens nucleus is the originating nucleus from which the abducens nerve emerges - a cranial nerve nucleus. ... The sensory trigeminal nerve nucleus is the largest of the cranial nerve nuclei, and extends through the whole of the brainstem, midbrain to medulla. ... The facial nerve is seventh of twelve paired cranial nerves. ... It has been suggested that Parasympatholytic be merged into this article or section. ... The nervus intermedius, or intermediate nerve, is the part of the facial nerve (cranial nerve VII) located between the motor component of the facial nerve and the vestibulocochlear nerve (cranial nerve VIII). ...


The nucleus has a dorsal and ventral region, with neurons in the dorsal region innervating muscles of the upper face and neurons in the ventral region innervating muscles of the lower face.


Classification

Because it innervates muscles derived from pharyngeal arches, the facial motor nucleus is considered part of the special visceral efferent (SVE) cell column, which also includes the trigeminal motor nucleus, nucleus ambiguus, and (arguably) the spinal accessory nucleus. Schematic of developing fetus with first, second and third arches labeled. ... The sensory trigeminal nerve nucleus is the largest of the cranial nerve nuclei, and extends through the whole of the brainstem, midbrain to medulla. ... The nucleus ambiguus (literally ambiguous nucleus) is a region of histologically disperse cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla. ... The spinal accessory nucleus lies within the cervical spinal cord (C1-C5) in the ventral horn. ...


Cortical input

The like all lower motor neurons, cells of the facial motor nucleus receive input from the primary motor cortex in the frontal lobe of the brain. Upper motor neurons of the cortex send axons that descend through the internal capsule and synapse on neurons in the facial motor nucleus. This pathway from the cortex to the brainstem is called the corticobulbar tract. The primary motor area is a group of networked cells in mammalian brains that controls movements of specific body parts associated with cell groups in that area of the brain. ... The frontal lobe is an area in the brain of vertebrates. ... Comparative brain sizes In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... Upper motor neurons, or Betz cells, are motoneurons located in the primary motor cortex. ... The internal capsule is an area of white matter in the brain that separates the caudate nucleus and the thalamus from the lenticular nucleus. ...


Interestingly, the neurons in the dorsal aspect of the facial motor nucleus receive inputs from both sides of the cortex, while those in the ventral aspect mainly receive contralateral inputs (i.e. from the opposite side of the cortex). The result is that both sides of the brain control the muscles of the upper face, while the right side of the brain controls the lower left side of the face, and the left side of the brain controls the lower right side of the face.


Effects of lesions

As a result of the corticobulbar input to the facial motor nucleus, an upper motor neuron lesion to fibers innervating the facial motor nucleus results in central seven. The syndrome is characterized by flaccid paralysis of the contralateral lower face. For example, a left corticobulbar lesion results in paralysis of the muscles that control the lower right quadrant of the face.


By contrast, a lower motor neuron lesion to the facial motor nucleus results in paralysis of facial muscles on the same side of the injury. This condition is known as Bell's palsy. Bells palsy (facial palsy) is characterised by facial drooping on the affected half, due to malfunction of the facial nerve (VII cranial nerve), which controls the muscles of the face. ...

Rhombencephalon (hindbrain)

MYELENCEPHALON/MEDULLA: arcuate nucleus of medulla, solitary nucleus, hypoglossal nucleus, nucleus ambiguus, olivary body, cuneate nucleus, accessory cuneate nucleus, gracile nucleus, inferior salivatory nucleus, nucleus raphe obscurus, nucleus raphe magnus, nucleus raphe pallidus, area postrema Wikipedia does not have an article with this exact name. ... The myelencephalon is a developmental categorization of a portion of the central nervous system. ... The medulla oblongata is the lower portion of the brainstem. ... Grays Fig. ... The solitary nucleus and tract are structures in the brainstem that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX), vagus (X) cranial nerves, as well as the cranial part of the accessory nerve (XI). ... The hypoglossal nucleus extends the length of the medulla, and being a motor nucleus, is close to the midline. ... The nucleus ambiguus (literally ambiguous nucleus) is a region of histologically disperse cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla. ... In anatomy, the olivary bodies or simply olives (Latin oliva and olivae, singular and plural, respectively) are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem. ... Cuneate nucleus is a wedge-shaped nucleus in the medulla. ... The accessory cuneate nucleus is located lateral to the cuneate nucleus in the medulla oblongata at the level of the sensory decussation (the crossing fibers of the posterior column/medial lemniscus tract). ... The swelling on the fasciculus gracilis is named the clava, and is produced by a subjacent nucleus of gray matter, the nucleus gracilis. ... The inferior salivatory nucleus is one of the components of the glossopharyngeal nerve, which stimulates secretion from the parotid gland. ... The nucleus raphe obscurus, despite the implications of its name, has some very specific functions and connections of afferent and efferent nature. ... The nucleus raphe magnus, located directly rostral to the raphe obscurus, is afferently stimulated from axons in the spinal cord and cerebellum. ... The nucleus raphe pallidus receives afferent connections from the periaqueductal gray, the paraventricular hypothalamic nucleus, central nucleus of the amygdala, lateral hypothalamic area, and parvocellular reticular nucleus. ... The lower end of the ala cinerea is crossed by a narrow translucent ridge, the funiculus separans, and between this funiculus and the clava, is a small tongue-shaped area, the area postrema. ...


METENCEPHALON/CEREBELLUM: cerebellar vermis, flocculus, arbor vitae The metencephalon is a developmental categorization of portions of the central nervous system. ... Figure 1a: A human brain, with the cerebellum in purple. ... Part of the structure of animal brains, the cerebellar vermis is a narrow, wormlike structure between the hemispheres of the cerebellum. ... The flocculus is a small lobe of the cerebellum at the posterior border of the middle cerebellar peduncle anterior to the biventer lobule; it is associated with the nodulus of the vermis; together, these two structures compose the vestibular part of the cerebellum. ... The arbor vitae (Latin for Tree of Life) is the cerebellar white matter, so called for its branched, tree-like appearance. ...


METENCEPHALON/PONS: pontine tegmentum, superior salivary nucleus, trapezoid body, pontine nuclei (superior olivary nucleus, trigeminal nerve nuclei, abducens nucleus, facial motor nucleus, cochlear nuclei, vestibular nuclei), locus ceruleus, paramedian pontine reticular formation, nucleus centralis superior The metencephalon is a developmental categorization of portions of the central nervous system. ... Position of the pons in the human brain The pons (sometimes pons Varolii after Costanzo Varolio) is a knob on the brain stem. ... The pontine tegmentum is a part of the pons of the brain involved in the initiation of REM sleep. ... The Superior salivary nucleus (or superior salivatory nucleus) of the facial nerve is a visceromotor cranial nerve nucleus located in the pontine tegmentum. ... The trapezoid body is part of the acoustic pathway. ... The pontine nuclei are a part of the pons which store the memory of intention during motor activity. ... // Anatomy The superior olivary nucleus (or superior olive) is a small mass of gray substance situated on the dorsal surface of the lateral part of the trapezoid body. ... The sensory trigeminal nerve nucleus is the largest of the cranial nerve nuclei, and extends through the whole of the brainstem, midbrain to medulla. ... The abducens nucleus is the originating nucleus from which the abducens nerve emerges - a cranial nerve nucleus. ... The cochlear nuclei consist of: (a) the lateral cochlear nucleus, corresponding to the tuberculum acusticum on the dorso-lateral surface of the inferior peduncle; and (b) the ventral or accessory cochlear nucleus, placed between the two divisions of the nerve, on the ventral aspect of the inferior peduncle. ... The nuclei of the vestibular nerve. ... The Locus ceruleus, also spelled locus caeruleus or locus coeruleus (Latin for the blue spot), is a nucleus in the brain stem responsible for physiological responses to stress and panic. ... The paramedian pontine reticular formation, or PPRF, is a brain region, without clearly defined borders, in the center of the pons. ... The nucleus centralis superior is composed of polygonal, fusiform and pyriform neurons and exists rostral to the nucleus raphe pontis. ...


FOURTH VENTRICLE: obex, median aperture The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. ... IrOBEX (or just OBEX) is a communications protocol that facilitates the exchange of binary objects between devices. ... The Median Aperture of the brain (apertura medialis ventriculi quarte) or Foramen of Magendie is an opening in the hollow nerve tube, connecting the 4th ventricle of the brain with the subarachnoid space The median aperture along with the paired lateral apertures (foramina of Luschka) are the primary routes for...


 
 

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