| spinal muscle of thorax | <anatomy, muscle> Origin, spinous processes of upper lumbar and two lower thoracic vertebrae; insertion, spinous processes of middle and upper thoracic vertebrae; action, supports and extends vertebral column; nerve supply, dorsal primary rami of thoracic and upper lumbar. Synonym: musculus spinalis thoracis, musculus spinalis dorsi, spinal muscle of thorax. (05 Mar 2000) |
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| spinal muscular atrophy | <radiology> 2nd most common autosomal recessive disease in Caucasians, pathology, degeneration of the spinal anterior horn cells, atrophy and wasting of skeletal muscles, types, SMA I = Werdnig-Hoffman disease: rapidly progressive, SMA II = intermediate form, SMA III = Kugelberg-Welander disease: slowly progressive, uncommon adult forms, usual presentations, floppy baby, arthrogryposis, muscle weakness in infancy, diagnosis, weakness and wasting with areflexia, electrophysiology shows anterior horm cell disease, genetics, linked to chromosome 5q., neuronal apoptosis inhibitory protein (NAIP) gene, survival motor neuron (SMN) gene (12 Dec 1998) |
| spinal nerve roots | The paired bundles of nerve fibres 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 efferent, comprising the axons of spinal motor and autonomic preganglionic neurons. There are, however, some exceptions to this afferent/efferent rule. (12 Dec 1998) |
| 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. (12 Dec 1998) |
| spinal nucleus of the trigeminus | The long sensory nucleus extending from the caudal border of the pontine sensory nucleus of the trigeminus down through the lateral region of the rhombencephalon into the upper three segments of the spinal cord's dorsal horn; it receives the fibres of the sensory root of the trigeminal nerve which descend along its lateral border as the spinal tract of trigeminal nerve. Synonym: nucleus tractus spinalis nervi trigemini, descending nucleus of the trigeminus, spinal nucleus of the trigeminus. (05 Mar 2000) |
| spinal osteophytosis | Outgrowth of immature bony processes from the vertebrae, reflecting the presence of degenerative disease and calcification. It includes cervical and lumbar spondylosis. (12 Dec 1998) |
| spinal paralysis | Loss of motor power due to a lesion of the spinal cord. Synonym: myeloparalysis, myeloplegia, rachioplegia. (05 Mar 2000) |
| spinal part of accessory nerve | <anatomy, nerve> 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 root. Synonym: radices spinales nervi accessorii, ramus externus nervi accessorii, pars spinalis nervi accessorii, spinal part of accessory nerve. (05 Mar 2000) |
| spinal part of arachnoid | That portion of the arachnoid which lies within the vertebral canal and surrounds the spinal cord and the vertebral portion of the subarachnoid space. It extends from the foramen magnum above to the S-2 vertebral level. Since the spinal cord ends at the L-2 vertebral level, a wide separation occurs between the arachnoid and pia mater, the lumbar cistern, filled with cerebrospinal fluid in which the cauda equina is suspended. Synonym: arachnoidea mater spinalis, spinal part of arachnoid. (05 Mar 2000) |
| spinal point | The centre of the root of the anterior nasal spine. Synonym: apophysary point, apophysial point, spinal point. (05 Mar 2000) |
| spinal puncture | Tapping of the subarachnoid space in the lumbar region, usually between the third and fourth lumbar vertebrae. (12 Dec 1998) |
| spinal quotient | The cerebrospinal index when 10 ml of cerebrospinal fluid have been removed. Synonym: Ayala's quotient, spinal quotient. (05 Mar 2000) |
| spinal reflex | A reflex arc involving the spinal cord. See: reflex arc. (05 Mar 2000) |
| spinal root of accessory nerve | <anatomy, nerve> 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 root. Synonym: radices spinales nervi accessorii, ramus externus nervi accessorii, pars spinalis nervi accessorii, spinal part of accessory nerve. (05 Mar 2000) |
| spinal shock | Transient depression or abolition of reflex activity below the level of an acute spinal cord injury or transection. (05 Mar 2000) |