Cranial Nerves: Twelve pairs of nerves that carry general afferent, visceral afferent, special afferent, somatic efferent, and autonomic efferent fibers.Cranial Nerve Diseases: Disorders of one or more of the twelve cranial nerves. With the exception of the optic and olfactory nerves, this includes disorders of the brain stem nuclei from which the cranial nerves originate or terminate.Cranial Nerve Injuries: Dysfunction of one or more cranial nerves causally related to a traumatic injury. Penetrating and nonpenetrating CRANIOCEREBRAL TRAUMA; NECK INJURIES; and trauma to the facial region are conditions associated with cranial nerve injuries.Cranial Nerve Neoplasms: Benign and malignant neoplasms that arise from one or more of the twelve cranial nerves.Abducens Nerve Diseases: Diseases of the sixth cranial (abducens) nerve or its nucleus in the pons. The nerve may be injured along its course in the pons, intracranially as it travels along the base of the brain, in the cavernous sinus, or at the level of superior orbital fissure or orbit. Dysfunction of the nerve causes lateral rectus muscle weakness, resulting in horizontal diplopia that is maximal when the affected eye is abducted and ESOTROPIA. Common conditions associated with nerve injury include INTRACRANIAL HYPERTENSION; CRANIOCEREBRAL TRAUMA; ISCHEMIA; and INFRATENTORIAL NEOPLASMS.Facial Nerve: The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and SALIVARY GLANDS, and convey afferent information for TASTE from the anterior two-thirds of the TONGUE and for TOUCH from the EXTERNAL EAR.Oculomotor Nerve Diseases: Diseases of the oculomotor nerve or nucleus that result in weakness or paralysis of the superior rectus, inferior rectus, medial rectus, inferior oblique, or levator palpebrae muscles, or impaired parasympathetic innervation to the pupil. With a complete oculomotor palsy, the eyelid will be paralyzed, the eye will be in an abducted and inferior position, and the pupil will be markedly dilated. Commonly associated conditions include neoplasms, CRANIOCEREBRAL TRAUMA, ischemia (especially in association with DIABETES MELLITUS), and aneurysmal compression. (From Adams et al., Principles of Neurology, 6th ed, p270)Sciatic Nerve: A nerve which originates in the lumbar and sacral spinal cord (L4 to S3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the TIBIAL NERVE and the PERONEAL NERVE.Glossopharyngeal Nerve: The 9th cranial nerve. The glossopharyngeal nerve is a mixed motor and sensory nerve; it conveys somatic and autonomic efferents as well as general, special, and visceral afferents. Among the connections are motor fibers to the stylopharyngeus muscle, parasympathetic fibers to the parotid glands, general and taste afferents from the posterior third of the tongue, the nasopharynx, and the palate, and afferents from baroreceptors and CHEMORECEPTOR CELLS of the carotid sinus.Oculomotor Nerve: The 3d cranial nerve. The oculomotor nerve sends motor fibers to the levator muscles of the eyelid and to the superior rectus, inferior rectus, and inferior oblique muscles of the eye. It also sends parasympathetic efferents (via the ciliary ganglion) to the muscles controlling pupillary constriction and accommodation. The motor fibers originate in the oculomotor nuclei of the midbrain.Peripheral Nerves: The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium.Hypoglossal Nerve Injuries: Traumatic injuries to the HYPOGLOSSAL NERVE.Trigeminal Nerve: The 5th and largest cranial nerve. The trigeminal nerve is a mixed motor and sensory nerve. The larger sensory part forms the ophthalmic, mandibular, and maxillary nerves which carry afferents sensitive to external or internal stimuli from the skin, muscles, and joints of the face and mouth and from the teeth. Most of these fibers originate from cells of the TRIGEMINAL GANGLION and project to the TRIGEMINAL NUCLEUS of the brain stem. The smaller motor part arises from the brain stem trigeminal motor nucleus and innervates the muscles of mastication.Abducens Nerve: The 6th cranial nerve which originates in the ABDUCENS NUCLEUS of the PONS and sends motor fibers to the lateral rectus muscles of the EYE. Damage to the nerve or its nucleus disrupts horizontal eye movement control.Vestibulocochlear Nerve: The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (COCHLEAR NERVE) which is concerned with hearing and a vestibular part (VESTIBULAR NERVE) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the SPIRAL GANGLION and project to the cochlear nuclei (COCHLEAR NUCLEUS). The fibers of the vestibular nerve arise from neurons of Scarpa's ganglion and project to the VESTIBULAR NUCLEI.Optic Nerve: The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.Nerve Fibers: Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.Mobius Syndrome: A syndrome of congenital facial paralysis, frequently associated with abducens palsy and other congenital abnormalities including lingual palsy, clubfeet, brachial disorders, cognitive deficits, and pectoral muscle defects. Pathologic findings are variable and include brain stem nuclear aplasia, facial nerve aplasia, and facial muscle aplasia, consistent with a multifactorial etiology. (Adams et al., Principles of Neurology, 6th ed, p1020)Nerve Compression Syndromes: Mechanical compression of nerves or nerve roots from internal or external causes. These may result in a conduction block to nerve impulses (due to MYELIN SHEATH dysfunction) or axonal loss. The nerve and nerve sheath injuries may be caused by ISCHEMIA; INFLAMMATION; or a direct mechanical effect.Accessory Nerve: The 11th cranial nerve which originates from NEURONS in the MEDULLA and in the CERVICAL SPINAL CORD. It has a cranial root, which joins the VAGUS NERVE (10th cranial) and sends motor fibers to the muscles of the LARYNX, and a spinal root, which sends motor fibers to the TRAPEZIUS and the sternocleidomastoid muscles.Laryngeal Nerve Injuries: Traumatic injuries to the LARYNGEAL NERVE.Ophthalmoplegia: Paralysis of one or more of the ocular muscles due to disorders of the eye muscles, neuromuscular junction, supporting soft tissue, tendons, or innervation to the muscles.Facial Paralysis: Severe or complete loss of facial muscle motor function. This condition may result from central or peripheral lesions. Damage to CNS motor pathways from the cerebral cortex to the facial nuclei in the pons leads to facial weakness that generally spares the forehead muscles. FACIAL NERVE DISEASES generally results in generalized hemifacial weakness. NEUROMUSCULAR JUNCTION DISEASES and MUSCULAR DISEASES may also cause facial paralysis or paresis.Trigeminal Nerve Diseases: Diseases of the trigeminal nerve or its nuclei, which are located in the pons and medulla. The nerve is composed of three divisions: ophthalmic, maxillary, and mandibular, which provide sensory innervation to structures of the face, sinuses, and portions of the cranial vault. The mandibular nerve also innervates muscles of mastication. Clinical features include loss of facial and intra-oral sensation and weakness of jaw closure. Common conditions affecting the nerve include brain stem ischemia, INFRATENTORIAL NEOPLASMS, and TRIGEMINAL NEURALGIA.Vestibulocochlear Nerve Diseases: Pathological processes of the VESTIBULOCOCHLEAR NERVE, including the branches of COCHLEAR NERVE and VESTIBULAR NERVE. Common examples are VESTIBULAR NEURITIS, cochlear neuritis, and ACOUSTIC NEUROMA. Clinical signs are varying degree of HEARING LOSS; VERTIGO; and TINNITUS.Nerve Regeneration: Renewal or physiological repair of damaged nerve tissue.Trochlear Nerve: The 4th cranial nerve. The trochlear nerve carries the motor innervation of the superior oblique muscles of the eye.Trigeminal Neuralgia: A syndrome characterized by recurrent episodes of excruciating pain lasting several seconds or longer in the sensory distribution of the TRIGEMINAL NERVE. Pain may be initiated by stimulation of trigger points on the face, lips, or gums or by movement of facial muscles or chewing. Associated conditions include MULTIPLE SCLEROSIS, vascular anomalies, ANEURYSMS, and neoplasms. (Adams et al., Principles of Neurology, 6th ed, p187)Paralysis: A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function. (From Adams et al., Principles of Neurology, 6th ed, p45)Facial Nerve Diseases: Diseases of the facial nerve or nuclei. Pontine disorders may affect the facial nuclei or nerve fascicle. The nerve may be involved intracranially, along its course through the petrous portion of the temporal bone, or along its extracranial course. Clinical manifestations include facial muscle weakness, loss of taste from the anterior tongue, hyperacusis, and decreased lacrimation.Cerebellopontine Angle: Junction between the cerebellum and the pons.Skull Base Neoplasms: Neoplasms of the base of the skull specifically, differentiated from neoplasms of unspecified sites or bones of the skull (SKULL NEOPLASMS).Facial Nerve Injuries: Traumatic injuries to the facial nerve. This may result in FACIAL PARALYSIS, decreased lacrimation and salivation, and loss of taste sensation in the anterior tongue. The nerve may regenerate and reform its original pattern of innervation, or regenerate aberrantly, resulting in inappropriate lacrimation in response to gustatory stimuli (e.g., "crocodile tears") and other syndromes.Trochlear Nerve Injuries: Traumatic injuries to the TROCHLEAR NERVE.Hypoglossal Nerve: The 12th cranial nerve. The hypoglossal nerve originates in the hypoglossal nucleus of the medulla and supplies motor innervation to all of the muscles of the tongue except the palatoglossus (which is supplied by the vagus). This nerve also contains proprioceptive afferents from the tongue muscles.Glomus Jugulare Tumor: A paraganglioma involving the glomus jugulare, a microscopic collection of chemoreceptor tissue in the adventitia of the bulb of the jugular vein. It may cause paralysis of the vocal cords, attacks of dizziness, blackouts, and nystagmus. It is not resectable but radiation therapy is effective. It regresses slowly, but permanent control is regularly achieved. (From Dorland, 27th ed; Stedman, 25th ed; DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, pp1603-4)Nerve Block: Interruption of NEURAL CONDUCTION in peripheral nerves or nerve trunks by the injection of a local anesthetic agent (e.g., LIDOCAINE; PHENOL; BOTULINUM TOXINS) to manage or treat pain.Nerve Endings: Branch-like terminations of NERVE FIBERS, sensory or motor NEURONS. Endings of sensory neurons are the beginnings of afferent pathway to the CENTRAL NERVOUS SYSTEM. Endings of motor neurons are the terminals of axons at the muscle cells. Nerve endings which release neurotransmitters are called PRESYNAPTIC TERMINALS.Petrous Bone: The dense rock-like part of temporal bone that contains the INNER EAR. Petrous bone is located at the base of the skull. Sometimes it is combined with the MASTOID PROCESS and called petromastoid part of temporal bone.Sural Nerve: A branch of the tibial nerve which supplies sensory innervation to parts of the lower leg and foot.Cavernous Sinus: An irregularly shaped venous space in the dura mater at either side of the sphenoid bone.Median Nerve: A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand.Nerve Crush: Treatment of muscles and nerves under pressure as a result of crush injuries.Peripheral Nerve Injuries: Injuries to the PERIPHERAL NERVES.Tibial Nerve: The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot.Skull Base: The inferior region of the skull consisting of an internal (cerebral), and an external (basilar) surface.Ulnar Nerve: A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm.Diplopia: A visual symptom in which a single object is perceived by the visual cortex as two objects rather than one. Disorders associated with this condition include REFRACTIVE ERRORS; STRABISMUS; OCULOMOTOR NERVE DISEASES; TROCHLEAR NERVE DISEASES; ABDUCENS NERVE DISEASES; and diseases of the BRAIN STEM and OCCIPITAL LOBE.Glossopharyngeal Nerve Diseases: Diseases of the ninth cranial (glossopharyngeal) nerve or its nuclei in the medulla. The nerve may be injured by diseases affecting the lower brain stem, floor of the posterior fossa, jugular foramen, or the nerve's extracranial course. Clinical manifestations include loss of sensation from the pharynx, decreased salivation, and syncope. Glossopharyngeal neuralgia refers to a condition that features recurrent unilateral sharp pain in the tongue, angle of the jaw, external auditory meatus and throat that may be associated with SYNCOPE. Episodes may be triggered by cough, sneeze, swallowing, or pressure on the tragus of the ear. (Adams et al., Principles of Neurology, 6th ed, p1390)Cranial Fossa, Posterior: The infratentorial compartment that contains the CEREBELLUM and BRAIN STEM. It is formed by the posterior third of the superior surface of the body of the sphenoid (SPHENOID BONE), by the occipital, the petrous, and mastoid portions of the TEMPORAL BONE, and the posterior inferior angle of the PARIETAL BONE.Femoral Nerve: A nerve originating in the lumbar spinal cord (usually L2 to L4) and traveling through the lumbar plexus to provide motor innervation to extensors of the thigh and sensory innervation to parts of the thigh, lower leg, and foot, and to the hip and knee joints.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Spinal Nerves: The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included.Cochlear Nerve: The cochlear part of the 8th cranial nerve (VESTIBULOCOCHLEAR NERVE). The cochlear nerve fibers originate from neurons of the SPIRAL GANGLION and project peripherally to cochlear hair cells and centrally to the cochlear nuclei (COCHLEAR NUCLEUS) of the BRAIN STEM. They mediate the sense of hearing.Neurilemmoma: A neoplasm that arises from SCHWANN CELLS of the cranial, peripheral, and autonomic nerves. Clinically, these tumors may present as a cranial neuropathy, abdominal or soft tissue mass, intracranial lesion, or with spinal cord compression. Histologically, these tumors are encapsulated, highly vascular, and composed of a homogenous pattern of biphasic fusiform-shaped cells that may have a palisaded appearance. (From DeVita Jr et al., Cancer: Principles and Practice of Oncology, 5th ed, pp964-5)Glossopharyngeal Nerve Injuries: Traumatic injuries to the GLOSSOPHARYNGEAL NERVE.Neuroradiography: Radiography of the central nervous system.Nerve Growth Factor: NERVE GROWTH FACTOR is the first of a series of neurotrophic factors that were found to influence the growth and differentiation of sympathetic and sensory neurons. It is comprised of alpha, beta, and gamma subunits. The beta subunit is responsible for its growth stimulating activity.Nerve Growth Factors: Factors which enhance the growth potentialities of sensory and sympathetic nerve cells.Facial Muscles: Muscles of facial expression or mimetic muscles that include the numerous muscles supplied by the facial nerve that are attached to and move the skin of the face. (From Stedman, 25th ed)Neuroma, Acoustic: A benign SCHWANNOMA of the eighth cranial nerve (VESTIBULOCOCHLEAR NERVE), mostly arising from the vestibular branch (VESTIBULAR NERVE) during the fifth or sixth decade of life. Clinical manifestations include HEARING LOSS; HEADACHE; VERTIGO; TINNITUS; and FACIAL PAIN. Bilateral acoustic neuromas are associated with NEUROFIBROMATOSIS 2. (From Adams et al., Principles of Neurology, 6th ed, p673)Vagus Nerve Injuries: Traumatic injuries to the VAGUS NERVE. Because the vagus nerve innervates multiple organs, injuries in the nerve fibers may result in any gastrointestinal organ dysfunction downstream of the injury site.Carotid Body Tumor: Benign paraganglioma at the bifurcation of the COMMON CAROTID ARTERIES. It can encroach on the parapharyngeal space and produce dysphagia, pain, and cranial nerve palsies.Phrenic Nerve: The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm.Duane Retraction Syndrome: A syndrome characterized by marked limitation of abduction of the eye, variable limitation of adduction and retraction of the globe, and narrowing of the palpebral fissure on attempted adduction. The condition is caused by aberrant innervation of the lateral rectus by fibers of the OCULOMOTOR NERVE.Radial Nerve: A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand.Recurrent Laryngeal Nerve: Branches of the vagus (tenth cranial) nerve. The recurrent laryngeal nerves originate more caudally than the superior laryngeal nerves and follow different paths on the right and left sides. They carry efferents to all muscles of the larynx except the cricothyroid and carry sensory and autonomic fibers to the laryngeal, pharyngeal, tracheal, and cardiac regions.Brain Stem: The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.Spinal Nerve Roots: Paired bundles of NERVE FIBERS entering and leaving the SPINAL CORD at each segment. The dorsal and ventral nerve roots join to form the mixed segmental spinal nerves. The dorsal roots are generally afferent, formed by the central projections of the spinal (dorsal root) ganglia sensory cells, and the ventral roots are efferent, comprising the axons of spinal motor and PREGANGLIONIC AUTONOMIC FIBERS.Meningeal Carcinomatosis: Primary or secondary neoplasm in the ARACHNOID or SUBARACHNOID SPACE. It appears as a diffuse fibrotic thickening of the MENINGES associated with variable degrees of inflammation.Hypoglossal Nerve Diseases: Diseases of the twelfth cranial (hypoglossal) nerve or nuclei. The nuclei and fascicles of the nerve are located in the medulla, and the nerve exits the skull via the hypoglossal foramen and innervates the muscles of the tongue. Lower brain stem diseases, including ischemia and MOTOR NEURON DISEASES may affect the nuclei or nerve fascicles. The nerve may also be injured by diseases of the posterior fossa or skull base. Clinical manifestations include unilateral weakness of tongue musculature and lingual dysarthria, with deviation of the tongue towards the side of weakness upon attempted protrusion.Hyperostosis: Increase in the mass of bone per unit volume.Olfactory Nerve: The 1st cranial nerve. The olfactory nerve conveys the sense of smell. It is formed by the axons of OLFACTORY RECEPTOR NEURONS which project from the olfactory epithelium (in the nasal epithelium) to the OLFACTORY BULB.Ophthalmic Nerve: A sensory branch of the trigeminal (5th cranial) nerve. The ophthalmic nerve carries general afferents from the superficial division of the face including the eyeball, conjunctiva, upper eyelid, upper nose, nasal mucosa, and scalp.Neural Conduction: The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.Temporal Bone: Either of a pair of compound bones forming the lateral (left and right) surfaces and base of the skull which contains the organs of hearing. It is a large bone formed by the fusion of parts: the squamous (the flattened anterior-superior part), the tympanic (the curved anterior-inferior part), the mastoid (the irregular posterior portion), and the petrous (the part at the base of the skull).Meningitis, Aseptic: A syndrome characterized by headache, neck stiffness, low grade fever, and CSF lymphocytic pleocytosis in the absence of an acute bacterial pathogen. Viral meningitis is the most frequent cause although MYCOPLASMA INFECTIONS; RICKETTSIA INFECTIONS; diagnostic or therapeutic procedures; NEOPLASTIC PROCESSES; septic perimeningeal foci; and other conditions may result in this syndrome. (From Adams et al., Principles of Neurology, 6th ed, p745)Nerve Tissue: Differentiated tissue of the central nervous system composed of NERVE CELLS, fibers, DENDRITES, and specialized supporting cells.Mandibular Nerve: A branch of the trigeminal (5th cranial) nerve. The mandibular nerve carries motor fibers to the muscles of mastication and sensory fibers to the teeth and gingivae, the face in the region of the mandible, and parts of the dura.Recurrent Laryngeal Nerve Injuries: Traumatic injuries to the RECURRENT LARYNGEAL NERVE that may result in vocal cord dysfunction.Hemifacial Spasm: Recurrent clonic contraction of facial muscles, restricted to one side. It may occur as a manifestation of compressive lesions involving the seventh cranial nerve (FACIAL NERVE DISEASES), during recovery from BELL PALSY, or in association with other disorders. (From Adams et al., Principles of Neurology, 6th ed, p1378)Racquet Sports: Games in which players use a racquet to hit a ball or similar type object.Skull Neoplasms: Neoplasms of the bony part of the skull.Axons: Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.Oculomotor Muscles: The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.Abducens Nerve Injury: Traumatic injury to the abducens, or sixth, cranial nerve. Injury to this nerve results in lateral rectus muscle weakness or paralysis. The nerve may be damaged by closed or penetrating CRANIOCEREBRAL TRAUMA or by facial trauma involving the orbit.Meningioma: A relatively common neoplasm of the CENTRAL NERVOUS SYSTEM that arises from arachnoidal cells. The majority are well differentiated vascular tumors which grow slowly and have a low potential to be invasive, although malignant subtypes occur. Meningiomas have a predilection to arise from the parasagittal region, cerebral convexity, sphenoidal ridge, olfactory groove, and SPINAL CANAL. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2056-7)Foramen Magnum: The large hole at the base of the skull through which the SPINAL CORD passes.Occipital Bone: Part of the back and base of the CRANIUM that encloses the FORAMEN MAGNUM.Sphenoid Sinus: One of the paired air spaces located in the body of the SPHENOID BONE behind the ETHMOID BONE in the middle of the skull. Sphenoid sinus communicates with the posterosuperior part of NASAL CAVITY on the same side.Rhombencephalon: The posterior of the three primitive cerebral vesicles of an embryonic brain. It consists of myelencephalon, metencephalon, and isthmus rhombencephali from which develop the major BRAIN STEM components, such as MEDULLA OBLONGATA from the myelencephalon, CEREBELLUM and PONS from the metencephalon, with the expanded cavity forming the FOURTH VENTRICLE.Spasm: An involuntary contraction of a muscle or group of muscles. Spasms may involve SKELETAL MUSCLE or SMOOTH MUSCLE.Splanchnic Nerves: The major nerves supplying sympathetic innervation to the abdomen. The greater, lesser, and lowest (or smallest) splanchnic nerves are formed by preganglionic fibers from the spinal cord which pass through the paravertebral ganglia and then to the celiac ganglia and plexuses. The lumbar splanchnic nerves carry fibers which pass through the lumbar paravertebral ganglia to the mesenteric and hypogastric ganglia.Tongue: A muscular organ in the mouth that is covered with pink tissue called mucosa, tiny bumps called papillae, and thousands of taste buds. The tongue is anchored to the mouth and is vital for chewing, swallowing, and for speech.Vertigo: An illusion of movement, either of the external world revolving around the individual or of the individual revolving in space. Vertigo may be associated with disorders of the inner ear (EAR, INNER); VESTIBULAR NERVE; BRAINSTEM; or CEREBRAL CORTEX. Lesions in the TEMPORAL LOBE and PARIETAL LOBE may be associated with FOCAL SEIZURES that may feature vertigo as an ictal manifestation. (From Adams et al., Principles of Neurology, 6th ed, pp300-1)Meningeal Neoplasms: Benign and malignant neoplastic processes that arise from or secondarily involve the meningeal coverings of the brain and spinal cord.Neurologic Examination: Assessment of sensory and motor responses and reflexes that is used to determine impairment of the nervous system.Microsurgery: The performance of surgical procedures with the aid of a microscope.Optic Nerve Injuries: Injuries to the optic nerve induced by a trauma to the face or head. These may occur with closed or penetrating injuries. Relatively minor compression of the superior aspect of orbit may also result in trauma to the optic nerve. Clinical manifestations may include visual loss, PAPILLEDEMA, and an afferent pupillary defect.Polyradiculoneuropathy: Diseases characterized by injury or dysfunction involving multiple peripheral nerves and nerve roots. The process may primarily affect myelin or nerve axons. Two of the more common demyelinating forms are acute inflammatory polyradiculopathy (GUILLAIN-BARRE SYNDROME) and POLYRADICULONEUROPATHY, CHRONIC INFLAMMATORY DEMYELINATING. Polyradiculoneuritis refers to inflammation of multiple peripheral nerves and spinal nerve roots.Horner Syndrome: A syndrome associated with defective sympathetic innervation to one side of the face, including the eye. Clinical features include MIOSIS; mild BLEPHAROPTOSIS; and hemifacial ANHIDROSIS (decreased sweating)(see HYPOHIDROSIS). Lesions of the BRAIN STEM; cervical SPINAL CORD; first thoracic nerve root; apex of the LUNG; CAROTID ARTERY; CAVERNOUS SINUS; and apex of the ORBIT may cause this condition. (From Miller et al., Clinical Neuro-Ophthalmology, 4th ed, pp500-11)Optic Nerve Diseases: Conditions which produce injury or dysfunction of the second cranial or optic nerve, which is generally considered a component of the central nervous system. Damage to optic nerve fibers may occur at or near their origin in the retina, at the optic disk, or in the nerve, optic chiasm, optic tract, or lateral geniculate nuclei. Clinical manifestations may include decreased visual acuity and contrast sensitivity, impaired color vision, and an afferent pupillary defect.Craniotomy: Any operation on the cranium or incision into the cranium. (Dorland, 28th ed)Carotid Artery, Internal: Branch of the common carotid artery which supplies the anterior part of the brain, the eye and its appendages, the forehead and nose.Meninges: The three membranes that cover the BRAIN and the SPINAL CORD. They are the dura mater, the arachnoid, and the pia mater.Herpes Zoster Oticus: A syndrome characterized by facial palsy in association with a herpetic eruption of the external auditory meatus. This may occasionally be associated with tinnitus, vertigo, deafness, severe otalgia, and inflammation of the pinna. The condition is caused by reactivation of a latent HERPESVIRUS 3, HUMAN infection which causes inflammation of the facial and vestibular nerves, and may occasionally involve additional cranial nerves. (From Adams et al., Principles of Neurology, 6th ed, p757)Thoracic Nerves: The twelve spinal nerves on each side of the thorax. They include eleven INTERCOSTAL NERVES and one subcostal nerve. Both sensory and motor, they supply the muscles and skin of the thoracic and abdominal walls.Nerve Fibers, Myelinated: A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.Neurofibromatosis 2: An autosomal dominant disorder characterized by a high incidence of bilateral acoustic neuromas as well as schwannomas (NEURILEMMOMA) of other cranial and peripheral nerves, and other benign intracranial tumors including meningiomas, ependymomas, spinal neurofibromas, and gliomas. The disease has been linked to mutations of the NF2 gene (GENES, NEUROFIBROMATOSIS 2) on chromosome 22 (22q12) and usually presents clinically in the first or second decade of life.Motor Neurons: Neurons which activate MUSCLE CELLS.Neurosurgical Procedures: Surgery performed on the nervous system or its parts.Brain Stem Neoplasms: Benign and malignant intra-axial tumors of the MESENCEPHALON; PONS; or MEDULLA OBLONGATA of the BRAIN STEM. Primary and metastatic neoplasms may occur in this location. Clinical features include ATAXIA, cranial neuropathies (see CRANIAL NERVE DISEASES), NAUSEA, hemiparesis (see HEMIPLEGIA), and quadriparesis. Primary brain stem neoplasms are more frequent in children. Histologic subtypes include GLIOMA; HEMANGIOBLASTOMA; GANGLIOGLIOMA; and EPENDYMOMA.Laryngeal Nerves: Branches of the VAGUS NERVE. The superior laryngeal nerves originate near the nodose ganglion and separate into external branches, which supply motor fibers to the cricothyroid muscles, and internal branches, which carry sensory fibers. The RECURRENT LARYNGEAL NERVE originates more caudally and carries efferents to all muscles of the larynx except the cricothyroid. The laryngeal nerves and their various branches also carry sensory and autonomic fibers to the laryngeal, pharyngeal, tracheal, and cardiac regions.Endarterectomy, Carotid: The excision of the thickened, atheromatous tunica intima of a carotid artery.Nerve Tissue ProteinsInfratentorial Neoplasms: Intracranial tumors originating in the region of the brain inferior to the tentorium cerebelli, which contains the cerebellum, fourth ventricle, cerebellopontine angle, brain stem, and related structures. Primary tumors of this region are more frequent in children, and may present with ATAXIA; CRANIAL NERVE DISEASES; vomiting; HEADACHE; HYDROCEPHALUS; or other signs of neurologic dysfunction. Relatively frequent histologic subtypes include TERATOMA; MEDULLOBLASTOMA; GLIOBLASTOMA; ASTROCYTOMA; EPENDYMOMA; CRANIOPHARYNGIOMA; and choroid plexus papilloma (PAPILLOMA, CHOROID PLEXUS).Sympathetic Nervous System: The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.Subarachnoid Space: The space between the arachnoid membrane and PIA MATER, filled with CEREBROSPINAL FLUID. It contains large blood vessels that supply the BRAIN and SPINAL CORD.Papilledema: Swelling of the OPTIC DISK, usually in association with increased intracranial pressure, characterized by hyperemia, blurring of the disk margins, microhemorrhages, blind spot enlargement, and engorgement of retinal veins. Chronic papilledema may cause OPTIC ATROPHY and visual loss. (Miller et al., Clinical Neuro-Ophthalmology, 4th ed, p175)Neurons, Afferent: Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Guillain-Barre Syndrome: An acute inflammatory autoimmune neuritis caused by T cell- mediated cellular immune response directed towards peripheral myelin. Demyelination occurs in peripheral nerves and nerve roots. The process is often preceded by a viral or bacterial infection, surgery, immunization, lymphoma, or exposure to toxins. Common clinical manifestations include progressive weakness, loss of sensation, and loss of deep tendon reflexes. Weakness of respiratory muscles and autonomic dysfunction may occur. (From Adams et al., Principles of Neurology, 6th ed, pp1312-1314)Sphenoid Bone: An irregular unpaired bone situated at the SKULL BASE and wedged between the frontal, temporal, and occipital bones (FRONTAL BONE; TEMPORAL BONE; OCCIPITAL BONE). Sphenoid bone consists of a median body and three pairs of processes resembling a bat with spread wings. The body is hollowed out in its inferior to form two large cavities (SPHENOID SINUS).Diabetic Neuropathies: Peripheral, autonomic, and cranial nerve disorders that are associated with DIABETES MELLITUS. These conditions usually result from diabetic microvascular injury involving small blood vessels that supply nerves (VASA NERVORUM). Relatively common conditions which may be associated with diabetic neuropathy include third nerve palsy (see OCULOMOTOR NERVE DISEASES); MONONEUROPATHY; mononeuropathy multiplex; diabetic amyotrophy; a painful POLYNEUROPATHY; autonomic neuropathy; and thoracoabdominal neuropathy. (From Adams et al., Principles of Neurology, 6th ed, p1325)Dura Mater: The outermost of the three MENINGES, a fibrous membrane of connective tissue that covers the brain and the spinal cord.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Branchial Region: A region, of SOMITE development period, that contains a number of paired arches, each with a mesodermal core lined by ectoderm and endoderm on the two sides. In lower aquatic vertebrates, branchial arches develop into GILLS. In higher vertebrates, the arches forms outpouchings and develop into structures of the head and neck. Separating the arches are the branchial clefts or grooves.Lingual Nerve: A sensory branch of the MANDIBULAR NERVE, which is part of the trigeminal (5th cranial) nerve. The lingual nerve carries general afferent fibers from the anterior two-thirds of the tongue, the floor of the mouth, and the mandibular gingivae.Mastoid: The posterior part of the temporal bone. It is a projection of the petrous bone.Pons: The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.Neurologic Manifestations: Clinical signs and symptoms caused by nervous system injury or dysfunction.Reflex, Abnormal: An abnormal response to a stimulus applied to the sensory components of the nervous system. This may take the form of increased, decreased, or absent reflexes.Bulbar Palsy, Progressive: A motor neuron disease marked by progressive weakness of the muscles innervated by cranial nerves of the lower brain stem. Clinical manifestations include dysarthria, dysphagia, facial weakness, tongue weakness, and fasciculations of the tongue and facial muscles. The adult form of the disease is marked initially by bulbar weakness which progresses to involve motor neurons throughout the neuroaxis. Eventually this condition may become indistinguishable from AMYOTROPHIC LATERAL SCLEROSIS. Fazio-Londe syndrome is an inherited form of this illness which occurs in children and young adults. (Adams et al., Principles of Neurology, 6th ed, p1091; Brain 1992 Dec;115(Pt 6):1889-1900)Intracranial Aneurysm: Abnormal outpouching in the wall of intracranial blood vessels. Most common are the saccular (berry) aneurysms located at branch points in CIRCLE OF WILLIS at the base of the brain. Vessel rupture results in SUBARACHNOID HEMORRHAGE or INTRACRANIAL HEMORRHAGES. Giant aneurysms (>2.5 cm in diameter) may compress adjacent structures, including the OCULOMOTOR NERVE. (From Adams et al., Principles of Neurology, 6th ed, p841)Tuberculosis, Meningeal: A form of bacterial meningitis caused by MYCOBACTERIUM TUBERCULOSIS or rarely MYCOBACTERIUM BOVIS. The organism seeds the meninges and forms microtuberculomas which subsequently rupture. The clinical course tends to be subacute, with progressions occurring over a period of several days or longer. Headache and meningeal irritation may be followed by SEIZURES, cranial neuropathies, focal neurologic deficits, somnolence, and eventually COMA. The illness may occur in immunocompetent individuals or as an OPPORTUNISTIC INFECTION in the ACQUIRED IMMUNODEFICIENCY SYNDROME and other immunodeficiency syndromes. (From Adams et al., Principles of Neurology, 6th ed, pp717-9)Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Botulinum Antitoxin: Antiserum given therapeutically in BOTULISM.Fatal Outcome: Death resulting from the presence of a disease in an individual, as shown by a single case report or a limited number of patients. This should be differentiated from DEATH, the physiological cessation of life and from MORTALITY, an epidemiological or statistical concept.PolyvinylsNerve Degeneration: Loss of functional activity and trophic degeneration of nerve axons and their terminal arborizations following the destruction of their cells of origin or interruption of their continuity with these cells. The pathology is characteristic of neurodegenerative diseases. Often the process of nerve degeneration is studied in research on neuroanatomical localization and correlation of the neurophysiology of neural pathways.Platybasia: A developmental deformity of the occipital bone and upper end of the cervical spine, in which the latter appears to have pushed the floor of the occipital bone upward. (Dorland, 27th ed)Sagittal Sinus Thrombosis: Formation or presence of a blood clot (THROMBUS) in the SUPERIOR SAGITTAL SINUS or the inferior sagittal sinus. Sagittal sinus thrombosis can result from infections, hematological disorders, CRANIOCEREBRAL TRAUMA; and NEUROSURGICAL PROCEDURES. Clinical features are primarily related to the increased intracranial pressure causing HEADACHE; NAUSEA; and VOMITING. Severe cases can evolve to SEIZURES or COMA.Spinal Cord: A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.Otitis Externa: Inflammation of the OUTER EAR including the external EAR CANAL, cartilages of the auricle (EAR CARTILAGE), and the TYMPANIC MEMBRANE.Tinnitus: A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of COCHLEAR DISEASES; VESTIBULOCOCHLEAR NERVE DISEASES; INTRACRANIAL HYPERTENSION; CRANIOCEREBRAL TRAUMA; and other conditions.Embolization, Therapeutic: A method of hemostasis utilizing various agents such as Gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and INTRACRANIAL ARTERIOVENOUS MALFORMATIONS, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage.Ear: The hearing and equilibrium system of the body. It consists of three parts: the EXTERNAL EAR, the MIDDLE EAR, and the INNER EAR. Sound waves are transmitted through this organ where vibration is transduced to nerve signals that pass through the ACOUSTIC NERVE to the CENTRAL NERVOUS SYSTEM. The inner ear also contains the vestibular organ that maintains equilibrium by transducing signals to the VESTIBULAR NERVE.Botulism: A disease caused by potent protein NEUROTOXINS produced by CLOSTRIDIUM BOTULINUM which interfere with the presynaptic release of ACETYLCHOLINE at the NEUROMUSCULAR JUNCTION. Clinical features include abdominal pain, vomiting, acute PARALYSIS (including respiratory paralysis), blurred vision, and DIPLOPIA. Botulism may be classified into several subtypes (e.g., food-borne, infant, wound, and others). (From Adams et al., Principles of Neurology, 6th ed, p1208)Vocal Cord Paralysis: Congenital or acquired paralysis of one or both VOCAL CORDS. This condition is caused by defects in the CENTRAL NERVOUS SYSTEM, the VAGUS NERVE and branches of LARYNGEAL NERVES. Common symptoms are VOICE DISORDERS including HOARSENESS or APHONIA.Vagus Nerve: The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).Chemoreceptor Cells: Cells specialized to detect chemical substances and relay that information centrally in the nervous system. Chemoreceptor cells may monitor external stimuli, as in TASTE and OLFACTION, or internal stimuli, such as the concentrations of OXYGEN and CARBON DIOXIDE in the blood.Radiosurgery: A radiological stereotactic technique developed for cutting or destroying tissue by high doses of radiation in place of surgical incisions. It was originally developed for neurosurgery on structures in the brain and its use gradually spread to radiation surgery on extracranial structures as well. The usual rigid needles or probes of stereotactic surgery are replaced with beams of ionizing radiation directed toward a target so as to achieve local tissue destruction.Cerebellar Diseases: Diseases that affect the structure or function of the cerebellum. Cardinal manifestations of cerebellar dysfunction include dysmetria, GAIT ATAXIA, and MUSCLE HYPOTONIA.Orbit: Bony cavity that holds the eyeball and its associated tissues and appendages.Miller Fisher Syndrome: A variant of the GUILLAIN-BARRE SYNDROME characterized by the acute onset of oculomotor dysfunction, ataxia, and loss of deep tendon reflexes with relative sparing of strength in the extremities and trunk. The ataxia is produced by peripheral sensory nerve dysfunction and not by cerebellar injury. Facial weakness and sensory loss may also occur. The process is mediated by autoantibodies directed against a component of myelin found in peripheral nerves. (Adams et al., Principles of Neurology, 6th ed, p1313; Neurology 1987 Sep;37(9):1493-8)Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)Medulla Oblongata: The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Maxillary Nerve: The intermediate sensory division of the trigeminal (5th cranial) nerve. The maxillary nerve carries general afferents from the intermediate region of the face including the lower eyelid, nose and upper lip, the maxillary teeth, and parts of the dura.Neural Crest: The two longitudinal ridges along the PRIMITIVE STREAK appearing near the end of GASTRULATION during development of nervous system (NEURULATION). The ridges are formed by folding of NEURAL PLATE. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the NEURAL TUBE.Ganglia: Clusters of multipolar neurons surrounded by a capsule of loosely organized CONNECTIVE TISSUE located outside the CENTRAL NERVOUS SYSTEM.Skull: The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.Dysarthria: Disorders of speech articulation caused by imperfect coordination of pharynx, larynx, tongue, or face muscles. This may result from CRANIAL NERVE DISEASES; NEUROMUSCULAR DISEASES; CEREBELLAR DISEASES; BASAL GANGLIA DISEASES; BRAIN STEM diseases; or diseases of the corticobulbar tracts (see PYRAMIDAL TRACTS). The cortical language centers are intact in this condition. (From Adams et al., Principles of Neurology, 6th ed, p489)Nerve Sheath Neoplasms: Neoplasms which arise from nerve sheaths formed by SCHWANN CELLS in the PERIPHERAL NERVOUS SYSTEM or by OLIGODENDROCYTES in the CENTRAL NERVOUS SYSTEM. Malignant peripheral nerve sheath tumors, NEUROFIBROMA, and NEURILEMMOMA are relatively common tumors in this category.Peripheral Nervous System Diseases: Diseases of the peripheral nerves external to the brain and spinal cord, which includes diseases of the nerve roots, ganglia, plexi, autonomic nerves, sensory nerves, and motor nerves.Receptors, Nerve Growth Factor: Cell surface receptors that bind NERVE GROWTH FACTOR; (NGF) and a NGF-related family of neurotrophic factors that includes neurotrophins, BRAIN-DERIVED NEUROTROPHIC FACTOR and CILIARY NEUROTROPHIC FACTOR.Bell Palsy: A syndrome characterized by the acute onset of unilateral FACIAL PARALYSIS which progresses over a 2-5 day period. Weakness of the orbicularis oculi muscle and resulting incomplete eye closure may be associated with corneal injury. Pain behind the ear often precedes the onset of paralysis. This condition may be associated with HERPESVIRUS 1, HUMAN infection of the facial nerve. (Adams et al., Principles of Neurology, 6th ed, p1376)Brain Diseases: Pathologic conditions affecting the BRAIN, which is composed of the intracranial components of the CENTRAL NERVOUS SYSTEM. This includes (but is not limited to) the CEREBRAL CORTEX; intracranial white matter; BASAL GANGLIA; THALAMUS; HYPOTHALAMUS; BRAIN STEM; and CEREBELLUM.Decompression, Surgical: A surgical operation for the relief of pressure in a body compartment or on a body part. (From Dorland, 28th ed)Meningitis: Inflammation of the coverings of the brain and/or spinal cord, which consist of the PIA MATER; ARACHNOID; and DURA MATER. Infections (viral, bacterial, and fungal) are the most common causes of this condition, but subarachnoid hemorrhage (HEMORRHAGES, SUBARACHNOID), chemical irritation (chemical MENINGITIS), granulomatous conditions, neoplastic conditions (CARCINOMATOUS MENINGITIS), and other inflammatory conditions may produce this syndrome. (From Joynt, Clinical Neurology, 1994, Ch24, p6)Taste Buds: Small sensory organs which contain gustatory receptor cells, basal cells, and supporting cells. Taste buds in humans are found in the epithelia of the tongue, palate, and pharynx. They are innervated by the CHORDA TYMPANI NERVE (a branch of the facial nerve) and the GLOSSOPHARYNGEAL NERVE.Carotid Artery, External: Branch of the common carotid artery which supplies the exterior of the head, the face, and the greater part of the neck.Brain Stem Infarctions: Infarctions that occur in the BRAIN STEM which is comprised of the MIDBRAIN; PONS; and MEDULLA OBLONGATA. There are several named syndromes characterized by their distinctive clinical manifestations and specific sites of ischemic injury.Central Nervous System Diseases: Diseases of any component of the brain (including the cerebral hemispheres, diencephalon, brain stem, and cerebellum) or the spinal cord.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Eyelids: Each of the upper and lower folds of SKIN which cover the EYE when closed.Denervation: The resection or removal of the nerve to an organ or part. (Dorland, 28th ed)Sciatic Neuropathy: Disease or damage involving the SCIATIC NERVE, which divides into the PERONEAL NERVE and TIBIAL NERVE (see also PERONEAL NEUROPATHIES and TIBIAL NEUROPATHY). Clinical manifestations may include SCIATICA or pain localized to the hip, PARESIS or PARALYSIS of posterior thigh muscles and muscles innervated by the peroneal and tibial nerves, and sensory loss involving the lateral and posterior thigh, posterior and lateral leg, and sole of the foot. The sciatic nerve may be affected by trauma; ISCHEMIA; COLLAGEN DISEASES; and other conditions. (From Adams et al., Principles of Neurology, 6th ed, p1363)Pituitary Apoplexy: The sudden loss of blood supply to the PITUITARY GLAND, leading to tissue NECROSIS and loss of function (PANHYPOPITUITARISM). The most common cause is hemorrhage or INFARCTION of a PITUITARY ADENOMA. It can also result from acute hemorrhage into SELLA TURCICA due to HEAD TRAUMA; INTRACRANIAL HYPERTENSION; or other acute effects of central nervous system hemorrhage. Clinical signs include severe HEADACHE; HYPOTENSION; bilateral visual disturbances; UNCONSCIOUSNESS; and COMA.Eye Diseases: Diseases affecting the eye.Evoked Potentials, Auditory, Brain Stem: Electrical waves in the CEREBRAL CORTEX generated by BRAIN STEM structures in response to auditory click stimuli. These are found to be abnormal in many patients with CEREBELLOPONTINE ANGLE lesions, MULTIPLE SCLEROSIS, or other DEMYELINATING DISEASES.Syndrome: A characteristic symptom complex.Epidermal Cyst: Intradermal or subcutaneous saclike structure, the wall of which is stratified epithelium containing keratohyalin granules.Cranial Sinuses: Large endothelium-lined venous channels situated between the two layers of DURA MATER, the endosteal and the meningeal layers. They are devoid of valves and are parts of the venous system of dura mater. Major cranial sinuses include a postero-superior group (such as superior sagittal, inferior sagittal, straight, transverse, and occipital) and an antero-inferior group (such as cavernous, petrosal, and basilar plexus).Nervous System: The entire nerve apparatus, composed of a central part, the brain and spinal cord, and a peripheral part, the cranial and spinal nerves, autonomic ganglia, and plexuses. (Stedman, 26th ed)Chorda Tympani Nerve: A branch of the facial (7th cranial) nerve which passes through the middle ear and continues through the petrotympanic fissure. The chorda tympani nerve carries taste sensation from the anterior two-thirds of the tongue and conveys parasympathetic efferents to the salivary glands.Strabismus: Misalignment of the visual axes of the eyes. In comitant strabismus the degree of ocular misalignment does not vary with the direction of gaze. In noncomitant strabismus the degree of misalignment varies depending on direction of gaze or which eye is fixating on the target. (Miller, Walsh & Hoyt's Clinical Neuro-Ophthalmology, 4th ed, p641)Carotid Artery Diseases: Pathological conditions involving the CAROTID ARTERIES, including the common, internal, and external carotid arteries. ATHEROSCLEROSIS and TRAUMA are relatively frequent causes of carotid artery pathology.Sarcoidosis: An idiopathic systemic inflammatory granulomatous disorder comprised of epithelioid and multinucleated giant cells with little necrosis. It usually invades the lungs with fibrosis and may also involve lymph nodes, skin, liver, spleen, eyes, phalangeal bones, and parotid glands.Gills: Paired respiratory organs of fishes and some amphibians that are analogous to lungs. They are richly supplied with blood vessels by which oxygen and carbon dioxide are exchanged directly with the environment.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Vestibular Nerve: The vestibular part of the 8th cranial nerve (VESTIBULOCOCHLEAR NERVE). The vestibular nerve fibers arise from neurons of Scarpa's ganglion and project peripherally to vestibular hair cells and centrally to the VESTIBULAR NUCLEI of the BRAIN STEM. These fibers mediate the sense of balance and head position.Skull Fractures: Fractures of the skull which may result from penetrating or nonpenetrating head injuries or rarely BONE DISEASES (see also FRACTURES, SPONTANEOUS). Skull fractures may be classified by location (e.g., SKULL FRACTURE, BASILAR), radiographic appearance (e.g., linear), or based upon cranial integrity (e.g., SKULL FRACTURE, DEPRESSED).Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Nerve Fibers, Unmyelinated: A class of nerve fibers as defined by their nerve sheath arrangement. The AXONS of the unmyelinated nerve fibers are small in diameter and usually several are surrounded by a single MYELIN SHEATH. They conduct low-velocity impulses, and represent the majority of peripheral sensory and autonomic fibers, but are also found in the BRAIN and SPINAL CORD.Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.Postoperative Complications: Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.Neck: The part of a human or animal body connecting the HEAD to the rest of the body.Reticular Formation: A region extending from the PONS & MEDULLA OBLONGATA through the MESENCEPHALON, characterized by a diversity of neurons of various sizes and shapes, arranged in different aggregations and enmeshed in a complicated fiber network.Nasopharyngeal Neoplasms: Tumors or cancer of the NASOPHARYNX.Central Nervous System: The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.