| dystonia, cranial | A term used to describe dystonia that affects the muscles of the head, face, and neck. Oromandibular dystonia affects the muscles of the jaw, lips, and tongue. The jaw may be pulled either open or shut, and speech and swallowing can be difficult. Spasmodic dysphonia involves the muscles of the throat that control speech. Also called spastic dysphonia or laryngeal dystonia, it causes strained and difficult speaking or breathy and effortful speech. Meige's syndrome is the combination of blepharospasm and oromandibular dystonia and sometimes spasmodic dysphonia. Spasmodic torticollis can be classified as a type of cranial dystonia. (12 Dec 1998) |
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| tenth cranial nerve | <anatomy, nerve> The vagus nerve enervates the gut (gastrointestinal tract), heart and larynx. Lesions of the tenth nerve usually result in a horse voice, but may also cause difficulty in swallowing or talking. Synonym: cranial nerve X. (27 Sep 1997) |
| third cranial nerve | <anatomy, nerve> Responsible for motor enervation of upper eyelid muscle, extraocular muscle and pupillary muscle. Lesions of the oculomotor nerve results in ptosis (dropping eyelid), deviation of the eyeball outward, double vision and a dilated pupil. (27 Sep 1997) |
| eighth cranial nerve | <anatomy, nerve> The vestibulocochlear nerve is responsible for the sense of hearing and balance (body position sense). Lesions of the eighth nerve can result in deafness, tinnitus, dizziness, vertigo and vomiting. Synonym: cranial nerve VIII. (27 Sep 1997) |
| eleventh cranial nerve | <anatomy, nerve> The accessory nerve enervates the sternocleidomastoid muscles and the trapezius muscles. Lesions of the eleventh result in drooping of the shoulder and inability to rotate the head away from the affected side. Synonym: cranial nerve XI. (27 Sep 1997) |
| twelfth cranial nerve | <anatomy, nerve> The hypoglossal nerve enervates the muscles of the tongue. Lesions of the twelfth cranial nerve result in deviation of the tongue toward the paralysed side and thick speech. Synonym: cranial nerve XII. (27 Sep 1997) |
| fifth cranial nerve | <anatomy, nerve> The trigeminal nerve is responsible for sensory enervation of the face and motor enervation to muscles of mastication (chewing). There are three divisions of the fifth cranial nerve, ophthalmic, maxillary and mandibular. Lesions of the sensory root to the trigeminal nerve can result in pain or loss of sensation in the face. Lesion of the motor root result in deviation of the jaw toward the paralysed side and difficulty chewing. Synonym: cranial nerve V. (27 Sep 1997) |
| first cranial nerve | Collective term denoting the numerous olfactory filaments: slender fascicles each composed of the thin, unmyelinated axons of 8 to 12 of the bipolar olfactory receptor cells in the olfactory portion of the nasal mucosa; the olfactory filaments pass through the cribriform plate of the ethmoid bone and enter the olfactory bulb, where they terminate in synaptic contact with mitral cells, tufted cells, and granule cells. See: olfactory tract. Synonym: nervi olfactorii, fila olfactoria, first cranial nerve, nerve of smell, olfactory fila. (05 Mar 2000) |
| fourth cranial nerve | <anatomy, nerve> The trochlear nerve controls an extraocular muscle. Lesions of this nerve will result in rotation of the eyeball upward and outward (and double vision). Synonym: cranial nerve IV. (27 Sep 1997) |
| abducens nucleus | Nucleus of abducent nervenucleus abducentis, a group of motor neurons in the lower part of the pons, innervating the lateral rectus muscle of the eye; unique among motor cranial nerve nuclei in that it consists of two distinct populations of neurons: neurons that give rise to fibres forming the abducens nerve root and those internuclear neurons whose processes cross the midline, ascend in the opposite medial longitudinal fasciculus, and terminate upon specific oculomotor neurons; considered a primary centre for mechanisms controlling conjugate horizontal gaze. Synonym: nucleus nervi abducentis. (05 Mar 2000) |
| accessory cuneate nucleus | A cell group lateral to the cuneate nucleus which receives posterior-root fibres corresponding to the proprioceptive innervation of the arm and hand; it projects to the cerebellum by way of the cuneocerebellar tract, and can be considered the upper-extremity equivalent of the thoracic nucleus. Synonym: nucleus cuneatus accessorius, external cuneate nucleus, lateral cuneate nucleus, Monakow's nucleus. (05 Mar 2000) |
| almond nucleus | Almond-shaped group of basal nuclei anterior to the inferior horn of the lateral ventricle of the brain, within the temporal lobe. The amygdala is part of the limbic system. (12 Dec 1998) |
| ambiguous nucleus | A very slender, longitudinal column of motor neurons in the ventrolateral medulla oblongata; its efferent fibres leave with the vagus and glossopharyngeal nerve and innervate the striated muscle fibres of the pharynx (including the musculus levator veli palatini) and the vocal cord muscles of the larynx. Synonym: ambiguous nucleus. (05 Mar 2000) |
| amygdaloid nucleus | Almond-shaped group of basal nuclei anterior to the inferior horn of the lateral ventricle of the brain, within the temporal lobe. The amygdala is part of the limbic system. (12 Dec 1998) |
| anterior extremity of caudate nucleus | The head or anterior extremity of the caudate nucleus projecting into the anterior horn of the lateral ventricle. Synonym: caput nuclei caudati, anterior extremity of caudate nucleus. (05 Mar 2000) |