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Medical Dictionary


neurapophysis (noor-a-pof′i-sis)
SYN: lamina of vertebral arch. [neur- + G. apophysis, offshoot]

neurapraxia (noor-a-prak′se-a)
The mildest type of focal nerve lesion that produces clinical deficits; localized loss of conduction along a nerve without axon degeneration; caused by a focal lesion, usually demyelinating, and followed by a complete recovery. Term is often misspelled (neuropraxia), and often used, incorrectly, as a synonym for nerve lesion. SEE ALSO: axonotmesis. [neur- + G. a- priv. + praxis, action]

neurarchy (noor′ar-ke)
The dominant action of the nervous system over the physical processes of the body. [neur- + G. arche, dominion]

neurasthenia (noor-as-the′ne-a)
An ill-defined condition, commonly accompanying or following depression, characterized by vague fatigue believed to be brought on by psychological factors. [neur- + G. astheneia, weakness] angiopathic n., angioparalytic n. an obsolete term for a form of mild n. in which the chief complaint is of a universal throbbing or sense of pulsation throughout the body. gastric n. a condition marked by vague epigastric atony and distention, and mild neurasthenic symptoms. n. gravis obsolete term for a condition of extreme and lasting n.. n. praecox obsolete term for a form of nervous exhaustion appearing in the adolescent period. primary n. obsolete term for n. praecox. pulsating n. obsolete term for angiopathic n.. sexual n. obsolete term for a form in which sexual erethism, weakness, or perversion is a marked symptom. traumatic n. obsolete term for posttraumatic syndrome.

neurasthenic (noor-as-then′ik)
Relating to, or suffering from, neurasthenia.

neuraxis (noo-rak′sis)
The axial, unpaired part of the central nervous system: spinal cord, rhombencephalon, mesencephalon, and diencephalon, in contrast to the paired cerebral hemisphere, or telencephalon.

neuraxon, neuraxone (noo-rak′son, -son)
Obsolete term for axon. [neur- + G. axon, axis]

neurectasis, neurectasia, neurectasy (noo-rek′ta-sis, noor-ek-ta′ze-a, -ek′ta-se)
The operation of stretching a nerve or nerve trunk. SYN: neurotension. [neur- + G. ektasis, extension]

neurectomy (noo-rek′to-me)
Excision of a segment of a nerve. SYN: neuroectomy. [neur- + G. ektome, excision] occipital n. excision of greater occipital nerve for the treatment of occipital neuralgia. presacral n. cutting of the presacral nerve to relieve severe dysmenorrhea. SYN: Cotte operation, presacral sympathectomy. retrogasserian n. SYN: trigeminal rhizotomy. vestibular n. transection of the vestibular division of the eighth cranial nerve.

neurectopia, neurectopy (noor-ek-to′pe-a, -ek′to-pe)
A condition in which a nerve follows an anomalous course. [neur- + G. ektopos, fr. ek, out of, + topos, place]

neurepithelium (noor′ep-i-the′le-um)
SYN: neuroepithelium.

See neur-.

neuridine (noor′i-den)
SYN: spermine.

neurilemma (noor-i-lem′a)
A cell that enfolds one or more axons of the peripheral nervous system; in myelinated fibers its plasma membrane forms the lamellae of myelin. SYN: neurolemma, sheath of Schwann. [neuri + G. lemma, husk]

neurilemoma (noor′i-le-mo′ma)
SYN: schwannoma. [neurilemma + G. -oma, tumor] acoustic n. schwannoma arising from cranial nerve VIII. Antoni type A n. relatively solid or compact arrangement of neoplastic tissue that consists of Schwann cells arranged in twisting bundles and associated with delicate reticulin fibers; the nuclei of the Schwann cells are frequently grouped in parallel rows (so-called palisades), and the nuclei and fibers sometimes form exaggerated tactile corpuscles, called Verocay bodies. Antoni type B n. relatively soft or loose arrangement of neoplastic tissue that consists of Schwann cells in a haphazard or nondescript type of arrangement among reticulin fibers and tiny cystlike foci; fat-laden macrophages may be observed in some of the larger neoplasms.

neurility (noo-ril′i-te)
The property, inherent in nerves, of conducting stimuli.

neurimotility (noor′i-mo-til′i-te)
SYN: nervimotility.

neurimotor (noor-i-mo′ter)
SYN: nervimotor.

neurine (noor′en)
A toxic amine that is a product of decomposing animal matter (dehydration of choline) and a poisonous constituent of mushrooms.

neurinoma (noor-i-no′ma)
Obsolete term for schwannoma. acoustic n. SYN: vestibular schwannoma.

neuritic (noo-rit′ik)
Relating to neuritis.

neuritis, pl .neuritides (noo-ri′tis, noo-rit′i-dez)
1. Inflammation of a nerve. 2. SYN: neuropathy. [neuri- + G. -itis, inflammation] adventitial n. inflammation of the sheath of a nerve. SEE ALSO: perineuritis. ascending n. inflammation progressing upward along a nerve trunk in a direction away from the periphery. axial n. SYN: parenchymatous n.. brachial n. SYN: neuralgic amyotrophy. central n. SYN: parenchymatous n.. descending n. inflammation progressing along a nerve trunk toward the periphery. Eichhorst n. SYN: interstitial n.. endemic n. SYN: beriberi. fallopian n. SYN: facial paralysis. interstitial n. inflammation of the connective tissue framework of a nerve. SYN: Eichhorst n.. intraocular n. inflammation of the retinal portion of the optic nerve. Leyden n. fatty degeneration of the fibers of the affected nerve. multiple n. SYN: polyneuropathy. occipital n. posttraumatic neck syndrome. optic n. inflammation of the optic nerve. SEE ALSO: neuromyelitis optica, retrobulbar n., papillitis. parenchymatous n. inflammation of the nervous substance proper, the axons, and myelin. SYN: axial n., central n.. retrobulbar n. optic n. without swelling of the optic disk. sciatic n. SYN: sciatica. segmental n. 1. inflammation occurring at several points along the course of a nerve; 2. segmental demyelinating neuropathy suboccipital n. posttraumatic neck syndrome. toxic n. n. caused by an endogenous or exogenous toxin. traumatic n. nerve lesion following an injury.

See neur-.

neuroallergy (noor-o-al′er-je)
An allergic reaction in nervous tissue.

neuroanastomosis (noor′o-an-as-to-mo′sis)
Surgical formation of a junction between nerves.

neuroanatomy (noor′o-a-nat′o-me)
The anatomy of the nervous system, usually specific to the central nervous system.

neuroarthropathy (noor′o-ar-throp′a-the)
A joint disorder caused by loss of joint sensation. See Charcot joint. [neuro- + G. arthron, joint, + pathos, suffering, disease]

neuroaugmentation (noor′o-awg-men-ta′shoon)
Use of electrical stimulation to supplement activity of the nervous system.

neuroaugmentive (noor′o-awg-men′tiv)
Related to neuroaugmentation.

The biology of the nervous system.

The theory that nerve cell bodies may move toward, or their axons may grow toward, the area from which they receive the most stimuli. [G. neuron, nerve + bios, life + taxis, arrangement]

neuroblast (noor′o-blast)
An embryonic nerve cell. [neuro- + G. blastos, germ]

neuroblastoma (noor′o-blas-to′ma)
A malignant neoplasm characterized by immature, only slightly differentiated nerve cells of embryonic type, i.e., neuroblasts; typical cells are relatively small (10–15 μm in diameter) with disproportionately large, darkly staining, vesicular nuclei and scant, palely acidophilic cytoplasm; they may be arranged in sheets, irregular clumps, or cordlike groups, as well as occurring individually and in pseudorosettes (with nuclei arranged peripherally about the centrally directed cytoplasmic processes); ordinarily, the stroma is sparse, and foci of necrosis and hemorrhage are not unusual. Neuroblastomas occur frequently in infants and children in the mediastinal and retroperitoneal regions (approximately 30% associated with the adrenal glands); widespread metastases to the liver, lungs, lymph nodes, cranial cavity, and skeleton are very common. olfactory n. a rare, often slowly growing malignant tumor of primitive nerve cells, usually arising in the olfactory area of the nasal cavity. SYN: olfactory esthesioneuroblastoma.

neuroborreliosis (noor′o-bor-rel′e-o′sis)
Inflammation or disease caused by infection of the central nervous system by a member of the genus Borrelia. It is frequently a late stage in the disease process, particularly in immunosuppressed individuals, such as those suffering from AIDS.

neurocardiac (noor-o-kar′de-ak)
1. Relating to the nerve supply of the heart. 2. Relating to a cardiac neurosis. [neuro- + G. kardia, heart]

neurocele (noor′o-sel)
Rarely used collective term for the central cavity of the cerebrospinal axis; the combined ventricles of the brain and central canal of the spinal cord. [neuro- + G. koilos, hollow]

neurochemistry (noor-o-kem′is-tre)
The science concerned with the chemical aspects of nervous system structure and function.

neurochitin (noor-o-ki′tin)
SYN: neurokeratin. [neuro- + G. chiton, tunic]

neurochorioretinitis (noor-o-kor′e-o-ret-in-i′tis)
Inflammation of the choroid, the retina, and the optic nerve.

neurochoroiditis (noor′o-ko-roy-di′tis)
Inflammation of the choroid and the optic nerve.

neurocladism (noo-rok′la-dizm)
The outgrowth of axons from the central stump to bridge the gap in a cut nerve. SYN: odogenesis. [neuro- + G. klados, a young branch]

neurocranium (noor-o-kra′ne-um) [TA]
Those bones of the skull enclosing the brain, as distinguished from the bones of the face. SYN: brain box&star, braincase, cranial vault, cranium cerebrale, cerebral cranium. [neuro- + G. kranion, skull] cartilaginous n. in the embryo, that part of the base of the skull first laid down in cartilage and then ossified. membranous n. the vault of the embryonic skull that is ossified in membrane.

neurocristopathy (noor′o-kris-top′a-the)
Developmental anomaly arising from maldevelopment of neural crest cells. [neuro- + L. crista, crest, + G. pathos, suffering]

neurocyte (noor′o-sit)
SYN: neuron. [neuro- + G. kytos, cell]

neurocytolysis (noor′o-si-tol′i-sis)
Destruction of neurons. [neuro- + G. kytos, cell, + lysis, dissolution]

neurocytoma (noor′o-si-to′ma)
A tumor of neuronal differentiation usually intraventricular in location, consisting of sheets of cells with uniform nuclei and occasional perivascular pseudorosette formation. [neuro- + G. kytos, cell, + -oma, tumor]

neurodendrite (noor-o-den′drit)
SYN: dendrite (1) .

neurodendron (noor-o-den′dron)
SYN: dendrite (1) .

neurodermatitis (noor′o-der-ma-ti′tis)
A chronic lichenified skin lesion, localized or disseminated. [neuro- + G. derma, skin, + -itis, inflammation]

neurodynamic (noor′o-di-nam′ik)
Pertaining to nervous energy. [neuro- + G. dynamis, force]

neurodynia (noor-o-din′e-a)
SYN: neuralgia. [neuro- + G. odyne, pain]

neuroectoderm (noor-o-ek′to-derm)
That central region of the early embryonic ectoderm that on further development forms the brain and spinal cord, and the neural crest cells that become the nerve cells and neurilemma or Schwann cells of the peripheral nervous system.

neuroectodermal (noor′o-ek-to-der′mal)
Relating to the neuroectoderm.

neuroectomy (noor-o-ek′to-me)
SYN: neurectomy.

neuroencephalomyelopathy (noor′o-en-sef′a-lo-mi-e-lop′a-the)
Disease of the brain, spinal cord, and nerves.

neuroendocrine (noor-o-en′do-krin)
1. Pertaining to the anatomic and functional relationships between the nervous system and the endocrine apparatus. 2. Descriptive of cells that release a hormone into the circulating blood in response to a neural stimulus. Such cells may compose a peripheral endocrine gland ( e.g., the insulin-secreting beta cells of the islets of Langerhans in the pancreas and the adrenaline-secreting chromaffin cells of the adrenal medulla); others are neurons in the brain ( e.g., the neurons of the supraoptic nucleus that release antidiuretic hormone from their axon terminals in the posterior lobe of the hypophysis).

neuroendocrinology (noor-o-en′do-krin-ol′o-je)
The specialty concerned with the anatomic and functional relationships between the nervous system and the endocrine apparatus.

neuroepithelial (noor′o-ep-i-the′le-al)
Relating to the neuroepithelium.

neuroepithelium (noor′o-ep-i-the′le-oom)
Epithelial cells specialized for the reception of external stimuli. Most neuroepithelial cells, notably the hair cells of the inner ear and the receptor cells of the taste buds, are not true neurons but transducer cells that stand in synaptic contact with the peripheral endings of sensory ganglion cells. The neuroepithelial receptor cells of the olfactory epithelium, by contrast, are true peripheral neurons whose extremely thin, unmyelinated axons compose the olfactory filaments that enter the olfactory bulb of the cerebral hemisphere. The NA also applies the term to the rods and cones of the retina. SYN: neurepithelium, neuroepithelial cells. n. of ampullary crest the specialized sensory hair cells in the ampullary crest of the ampulla of each semicircular duct. n. of macula the specialized sensory hair cells of the epithelium of the macula sacculi and macula utriculi. SEE ALSO: macula.

neurofibrae postganglionicae SYN: postganglionic. neurofibrae preganglionicae SYN: preganglionic nerve fibers, under fiber. neurofibrae somaticae [TA] SYN: somatic nerve fibers, under fiber.

neurofibril (noor-o-fi′bril)
A filamentous structure seen with the light microscope in the nerve cell's body, dendrites, axon, and sometimes synaptic endings, as aggregations of much finer ultramicroscopic elements, the neurofilaments and microtubules; their functional significance remains to be established.

neurofibrillar (noor-o-fi′bri-ler)
Relating to neurofibrils.

neurofibroma (noor′o-fi-bro′ma)
A moderately firm, benign, encapsulated tumor resulting from proliferation of Schwann cells in a disorderly pattern that includes portions of nerve fibers; in neurofibromatosis, neurofibromas are multiple. SYN: fibroneuroma. plexiform n. a type of n., representing an anomaly rather than a true neoplasm, in which the proliferation of Schwann cells occurs from the inner aspect of the nerve sheath, thereby resulting in an irregularly thickened, distorted, tortuous structure; in some instances, the process extends along the course of the nerve and may eventually involve the spinal roots and the spinal cord; seen most frequently in neurofibromatosis. SYN: fibrillary neuroma, plexiform neuroma. storiform n. SYN: pigmented dermatofibrosarcoma protuberans.

neurofibromatosis (noor′o-fi-bro-ma-to′sis)
Under this heading are grouped two distinct hereditary disorders, formerly labeled peripheral and central n., but now entitled n. type 1 and type 2. Type 1 (peripheral) n., [MIM*162200] by far the most common of the two types, is characterized clinically by the combination of patches of hyperpigmentation and cutaneous and subcutaneous tumors. The hyperpigmented skin areas, present from birth and found anywhere on the body surface, can vary markedly in size and color—the dark brown ones are called café-au-lait spots. The multiple cutaneous and subcutaneous tumors, nerve sheath neoplasms, called neurofibromas, can develop anywhere along the peripheral nerve fibers, from the roots distally. Neurofibromas can become quite large, causing a major disfigurement, eroding bone, and compressing various peripheral nerve structures; a small hamartoma (Lisch nodule) can be found in the iris of almost all patients. Type 1 n., also called von Recklinghausen disease, has autosomal dominant inheritance, with the gene locus on chromosome 17q11, and is caused by mutation in the NF1 gene that encodes neurofibromin. Type 2 (central) n. [MIM*101000] has few cutaneous manifestations, and consists primarily of bilateral (less often, unilateral) acoustic neuromas, causing deafness, often accompanied by other intracranial and paraspinal neoplasms, such as meningiomas and gliomas. Type 2 n. also has autosomal dominant inheritance, but the gene locus is on 22q11, caused by mutation in the NF2 gene encoding the product merlin. SYN: elephant man's disease (2) . abortive n. SYN: incomplete n.. central type n. type 2 n.. See n.. incomplete n. multiple neurofibromas with minimal manifestations, perhaps limited to café-au-lait spots; individuals with minimal lesions may have offspring with severe involvement. SYN: abortive n..

neurofilament (noor-o-fil′a-ment)
A class of intermediate filaments found in neurons.


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