| fractional spinal anaesthesia | Insertion of a catheter into the spinal subarachnoid space and leaving it in situ to permit serial intermittent injection of local anaesthetic solution for prolonged spinal anaesthesia. Synonym: fractional spinal anaesthesia. (05 Mar 2000) |
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| loops of spinal nerves | Loops of the spinal nerves, connecting ventral primary rami of the spinal nerves. Synonym: ansae nervorum spinalium. (05 Mar 2000) |
| low spinal anaesthesia | Spinal anaesthesia in which the level of sensory denervation extends to the tenth or eleventh thoracic dermatome. (05 Mar 2000) |
| lumbar enlargement of spinal cord | A spindle-shaped swelling of the spinal cord beginning at the level of the tenth thoracic vertebra and tapering into the medullary cone, with maximum thickness opposite the last thoracic vertebra, consequential to the innervation of the lower limb. Synonym: intumescentia lumbalis, lumbar enlargement of spinal cord. (05 Mar 2000) |
| lumbar part of spinal cord | Portion of spinal cord which consists of the five lumbar segments (L1-L5) and from which five pairs of lumbar spinal nerves originate; in the adult it is located in the T10-L1 portion of the vertebral canal, and is enlarged relative to other parts of the cord due to its involvement in innervation of the lower limb. (05 Mar 2000) |
| lumbar segments of spinal cord | The five lumbar segments of the spinal cord which give rise to the five pairs of lumbar spinal nerves and constitute the lumbar part of the spinal cord. Synonym: segmenta medullae spinalis lumbaria. (05 Mar 2000) |
| 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) |
| anterodorsal thalamic nucleus | anterodorsal thalamic nucleus |
| anteromedial thalamic nucleus | anteromedial thalamic nucleus |
| anteroventral thalamic nucleus | anteroventral thalamic nucleus |