- 1. The primary or beginning portion of any part, as of a nerve at its origin from the brainstem or spinal cord. SYN: radix (1) [TA]. 2. SYN: r. of tooth. 3. The descending underground portion of a plant; it absorbs water and nutrients, provides support, and stores nutrients. For roots of pharmacologic significance not listed below, see specific names. [A.S. rot]- anterior r. of spinal nerve [TA] the motor r. of a spinal nerve. SYN: radix anterior nervi spinalis [TA], motor r. of spinal nerve, radix motoria nervi spinalis, ventral r. of spinal nerve, radix ventralis nervi spinalis.- buccal r. of tooth [TA] r. of a multirooted tooth which is located toward the buccal side of the alveolar ridge. SYN: radix buccalis [TA].- clinical r. of tooth [TA] that portion of a tooth embedded in the investing structures; the portion of a tooth not visible in the oral cavity. SYN: radix clinica dentis [TA].- cochlear r. of VIII nerve one of the components of the vestibulocochlear nerve; it is made up of the central processes of the bipolar neurons that compose the spiral (cochlear) ganglion in the spiral canal of the modiolus of the bony cochlea; the cochlear r. enters the cranial cavity by passing in fascicles through the spiral foraminous tract at the bottom of the internal auditory meatus; it enters the brainstem through the pontomedullary groove, closely adhering to the caudoventral aspect of the vestibular r., and distributes its fibers to the ventral and dorsal cochlear nuclei in the floor of the lateral recess of the fourth ventricle. SYN: radix inferior nervi vestibulocochlearis.- cranial r. of accessory nerve [TA] the roots of the accessory nerve that arise from the medulla; the nerve fibers of the cranial r. join the intracranial portion of the vagus nerve and are distributed to the pharyngeal plexus, providing the motor innervation of the soft palate (except the tensor veli palati) and the pharynx. SEE ALSO: accessory nerve [CN XI]. SYN: radix cranialis nervi accessorii [TA], pars vagalis nervi accessorii, vagal part of accessory nerve, accessory portion of spinal accessory nerve.- Culver r. SYN: leptandra.- r. of facial nerve fibers running from the facial motor nucleus upward to the facial colliculus where they curve around the abducens nucleus and then pass peripherally between the superior olive and sensory nucleus of the trigeminal, to emerge as the facial nerve from the pontomedullary groove. SYN: radix nervi facialis.- hair r. the part of a hair that is embedded in the hair follicle, its lower succulent extremity capping the dermal papilla pili in the deep bulbous portion of the follicle. SYN: radix pili.- inferior r. of ansa cervicalis [TA] fibers from the second and third cervical nerves that pass forward and downward along the internal jugular vein; they contribute to the ansa cervicalis and innervate the infrahyoid muscles. SYN: radix inferior ansae cervicalis [TA], inferior limb of ansa cervicalis, descendens cervicalis.- lateral r. of median nerve [TA] the part of the median nerve arising from the lateral cord of the brachial plexus. SYN: radix lateralis nervi mediani [TA].- lateral r. of optic tract [TA] the larger division of the posterior end of the optic tract that terminates in the lateral geniculate body. SYN: radix lateralis tractus optici [TA].- r. of lung [TA] all the structures entering or leaving the lung at the hilum, forming a pedicle invested with the pleura; includes the bronchi, pulmonary artery and veins, bronchial arteries and veins, lymphatics, and nerves. SYN: radix pulmonis [TA].- May apple r. SYN: podophyllum resin.- medial r. of median nerve [TA] the part of the median nerve coming from the medial cord of the brachial plexus. SYN: radix medialis nervi mediani [TA].- medial r. of optic tract [TA] the smaller division of the posterior end of the optic tract that disappears under the medial geniculate body. SYN: radix medialis tractus optici [TA].- r. of mesentery [TA] the origin of the mesentery of the small intestine (jejunum and ileum) from the posterior parietal peritoneum; about 9 inches (23 cm) in length, it extends from the duodenojejunal flexure (just to the left of the midline at the L2 vertebral level) to the ileocecal junction (iliac fossa). SYN: radix mesenterii [TA].- motor r. of trigeminal nerve [TA] the smaller r. of the trigeminal nerve, composed of fibers originating from the trigeminal motor nucleus and emerging from the pons medial to the much larger sensory r., to join the mandibular nerve; it carries motor and proprioceptive fibers to the muscles derived from the first bronchial (mandibular) arch, including the four muscles of mastication, plus the mylohyoid, anterior belly of the digastric, and the tensores tympani and veli palati. SYN: radix motoria nervi trigemini [TA], masticator nerve, portio minor nervi trigemini.- nerve r. one of the two bundles of nerve fibers (posterior and anterior roots) emerging from the spinal cord that join to form a single segmental (mixed) spinal nerve; some of the cranial nerves are similarly formed by the union of two roots, in particular the fifth or trigeminal nerve.- r. of nose [TA] the upper least protruding portion of the external nose situated between the two orbits. SYN: radix nasi [TA].- roots of olfactory tract, lateral and medial the two fiber bands that form the caudal continuation of the olfactory tract that, upon diverging, enclose the olfactory tubercle.- parasympathetic r. of ciliary ganglion [TA] a branch of the oculomotor nerve supplying parasympathetic preganglionic nerve fibers to the ciliary ganglion. SYN: radix parasympathica ganglii ciliaris [TA], oculomotor r. of ciliary ganglion, radix nervi oculomotorii ad ganglion ciliare, radix oculomotoria ganglii ciliaris, branch of oculomotor nerve to ciliary ganglion, motor r. of ciliary ganglion, radix brevis ganglii ciliaris, short r. of ciliary ganglion.- r. of penis [TA] the proximal attached part of the penis, including the two crura and the bulb. SYN: radix penis [TA].- posterior r. of spinal nerve [TA] the sensory r. of a spinal nerve, having a dorsal r. ganglion containing the nerve cell bodies of the fibers conveyed by the r. in its distal end. SYN: radix posterior nervi spinalis [TA], dorsal r. of spinal nerve, radix sensoria nervi spinalis, sensory r. of spinal nerve, radix dorsalis nervi spinalis.- sensory r. of ciliary ganglion [TA] sensory fibers passing from the eyeball through the ciliary ganglion to their cell bodies in the trigeminal ganglion via the nasociliary nerve. SYN: radix sensoria ganglii ciliaris [TA], nasociliary r. of ciliary ganglion, radix nasociliaris ganglii ciliaris, ramus communicans nervi nasociliaris cum ganglio ciliari, communicating branch of nasociliary nerve with ciliary ganglion, long r. of ciliary ganglion, radix longa ganglii ciliaris.- sensory r. of pterygopalatine ganglion [TA] the ganglionic branches, two short sensory branches of the maxillary nerve in the pterygopalatine fossa, the fibers of which pass through the pterygopalatine ganglion without synapse. SYN: radix sensoria ganglii pterygopalatini [TA], ganglionic branches of maxillary nerve to pterygopalatine ganglion, rami ganglionici nervi maxillaris, ganglionic branches of maxillary nerve, nervi pterygopalatini, nervi sphenopalatini, pterygopalatine nerves, rami ganglionares.- sensory r. of sublingual ganglion [TA] branch or branches of the lingual nerve conveying sensory fibers to the sublingual ganglion that traverse the ganglion without synapse for distribution to the floor of the mouth. SYN: radix sensoria ganglii sublingualis [TA], ganglionic branches of lingual nerve to sublingual ganglion, ganglionic branches of lingual nerve to submandibular ganglion, rami communicantes ganglii sublingualis cum nervo linguali.- sensory r. of submandibular ganglion [TA] motor roots of submandibular ganglion; communicating branches between submandibular ganglion and lingual nerve. SYN: radix sensoria ganglii submandibularis [TA], rami communicantes ganglii submandibularis cum nervo linguali, ganglionic branches of lingual nerve.- sensory r. of trigeminal nerve [TA] the large sensory r. of the trigeminal (or fifth cranial) nerve, extending from the semilunar ganglion into the pons through the middle cerebellar peduncle or brachium pontis, immediately lateral to the small motor r.. SYN: radix sensoria nervi trigemini [TA], portio major nervi trigemini.- spinal r. of accessory nerve [TA] originates from the upper five or six cervical spinal segments, emerges from the lateral surface of the spinal cord and ascends through the foramen magnum to join the cranial r.. SYN: radix spinalis nervi accessorii [TA], pars spinalis nervi accessorii, spinal part of accessory nerve.- superior r. of ansa cervicalis [TA] the fibers that arise from the first and second cervical nerves, accompany the hypoglossal nerve, then branch off to meet the inferior r. in the ansa cervicalis; they innervate the infrahyoid muscles. SYN: radix superior ansae cervicalis [TA], superior limb of ansa cervicalis, descendens hypoglossi, descending branch of hypoglossal nerve.- sympathetic r. of ciliary ganglion [TA] postganglionic fibers, having cell bodies in the superior cervical ganglion, branching from the carotid plexus passing through the ciliary ganglion without synapse to reach the eyeball. SYN: radix sympathica ganglii ciliaris [TA].- sympathetic r. of otic ganglion [TA] branch arising from the periarterial plexus of the middle meningeal artery, bringing postsynaptic sympathetic fibers from the superior cervical sympathetic ganglion that traverse the ganglion without synapse for distribution to blood vessel s within the parotid gland. SYN: radix sympathica ganglii otici [TA].- sympathetic r. of sublingual ganglion [TA] branch arising from the periarterial plexus of the facial artery, bringing postsynaptic sympathetic fibers from the superior cervical sympathetic ganglion that traverse the ganglion without synapse for distribution to blood vessel s of the sublingual gland. SYN: radix sympathica ganglii sublingualis [TA].- sympathetic r. of submandibular ganglion [TA] branch to the submandibular ganglion composed of postsynaptic sympathetic fibers from the internal carotid plexus conveyed largely by a periarterial plexus of the facial artery. SYN: radix sympathica ganglii submandibularis [TA], ramus sympathicus (sympatheticus) ad ganglion submandibulare, sympathetic branch to submandibular ganglion.- r. of tongue [TA] the posterior attached portion of the tongue. SYN: radix linguae [TA], base of tongue.- r. of tooth [TA] that part of a tooth below the neck, covered by cementum rather than enamel, and attached by the periodontal ligament to the alveolar bone. SYN: radix dentis [TA], radix (2) [TA], r. (2) [TA].- roots of trigeminal nerve collective term for the sensory r. of trigeminal nerve and motor r. of trigeminal nerve. SYN: radices nervi trigemini.- tuberous r. a r. that is swollen for food storage; tuberous primary roots occur in aconite, beet, and carrot; tuberous secondary roots occur in plants of the Umbelliferae; and tuberous adventitious roots occur in jalap and sweet potato.- vestibular r. vestibular r. of VIII nerve, a collective term for those sensory fibers of the 8th cranial nerve (vestibulocochlear) that originate from the vestibular labyrinth, have their cell bodies of origin in the vestibular ganglion, and function in the sphere of balance and equilibrium; centrally these fibers end primarily in the vestibular nuclei of the brainstem and in the cerebellum. SYN: radix superior nervi vestibulocochlearis, radix vestibularis, vestibular r. of vestibulocochlear nerve.
* * *root 'rüt, 'ru̇t n1 a) the usu. underground part of a seed plant body that functions as an organ of absorption, aeration, and food storage or as a means of anchorage and support and that differs from a stem esp. in lacking nodes, buds, and leavesb) any subterranean plant part (as a true root or a bulb, tuber, rootstock, or other modified stem) esp. when fleshy and edible2 a ) (1) the part of a tooth within the socket (2) any of the processes into which the root of a tooth is often dividedb) the enlarged basal part of a hair within the skin called also hair rootc) the proximal end of a nerve esp one or more bundles of nerve fibers joining the cranial and spinal nerves with their respective nuclei and columns of gray matter see DORSAL ROOT, VENTRAL ROOTd) the part of an organ or physical structure by which it is attached to the body <the \root of the tongue>root·less -ləs adj
* * *n.1. (in neurology) a bundle of nerve fibres at its emergence from the spinal cord. The 31 pairs of spinal nerves have two roots on each side, an anterior root containing motor nerve fibres and a posterior root containing sensory fibres. The roots merge outside the cord to form mixed nerves.2. (in dentistry) the part of a tooth that is not covered by enamel and is normally attached to the alveolar bone by periodontal fibres.3. the origin of any structure, i.e. the point at which it diverges from another structure. Anatomical name: radix.
* * *(rt) 1. radix. 2. the lowermost part of a plant or other structure.
Medical dictionary. 2011.