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1. A short, sharp, thornlike process of bone; a spinous process. SYN: spina [TA]. 2. SYN: vertebral column. [L. spina]
- anterior inferior iliac s. [TA] s. on the anterior border of the ilium between the anterior superior iliac s. and the acetabulum; site of origin for the direct head of the rectus femoris muscle. SYN: spina iliaca anterior inferior [TA].
- anterior nasal s. of maxilla [TA] a pointed projection at the anterior extremity of the intermaxillary suture; the tip, as seen on a lateral cephalometric radiograph, is used as a cephalometric landmark. SYN: spina nasalis anterior corporis maxillae [TA], anterior nasal s..
- anterior superior iliac s. [TA] the anterior extremity of the iliac crest, which provides attachment for the inguinal ligament and the sartorius muscle. SYN: spina iliaca anterior superior [TA].
- cleft s. See spina bifida.
- dendritic spines variably long excrescences of nerve cell dendrites, varying in shape from small knobs to thornlike or filamentous processes, usually more numerous on distal dendrite arborizations than on the proximal part of dendritic trunks; they are a preferential site of synaptic axodendritic contact; sparse or absent in some types of nerve cells (motor neurons, the large cells of the globus pallidus, stellate cells of the cerebral cortex), exceedingly numerous in others such as the pyramidal cells of the cerebral cortex and the Purkinje cells of the cerebellar cortex. SYN: dendritic thorns, gemmule (2).
- greater tympanic s. [TA] the anterior edge of the tympanic notch (of Rivinus). SYN: spina tympanica major [TA].
- s. of helix [TA] an anteriorly directed s. at the extremity of the crus of the helix of the auricle. SYN: spina helicis [TA], apophysis helicis.
- hemal s. the middle point on the underside of the hemal arch of a vertebra in lower vertebrates; considered by some to be represented by the sternum in humans.
- Henle s. SYN: suprameatal s..
- iliac s. anterior inferior iliac s., anterior superior iliac s., posterior inferior iliac s., posterior superior iliac s..
- ischial s. [TA] a pointed process from the posterior border of the ischium on a level with the lower border of the acetabulum; gives attachment to the coccygeus muscle and sacrospinous ligament; the pudendal nerve passes dorsal to the ischial s., which is palpable per vagina or rectum, and thus is used as a target for the needle tip in administering a pudendal nerve block. SYN: spina ischiadica [TA], ischiadic s., sciatic s..
- lesser tympanic s. [TA] the posterior edge of the tympanic notch (of Rivinus). SYN: spina tympanica minor [TA].
- meatal s. SYN: suprameatal s..
- mental s. [TA] a slight projection, sometimes two (superior and inferior), in the middle line of the posterior surface of the body of the mandible, giving attachment to the geniohyoid muscle (below) and the genioglossus (above). SYN: spina mentalis (inferior et superior) [TA], genial tubercle, spinae geniorum inferior et superior.
- nasal s. of frontal bone [TA] a projection from the center of the nasal part of the frontal bone, which lies between and articulates with the nasal bones and the perpendicular plate of the ethmoid. SYN: spina nasalis ossis frontalis [TA].
- neural s. the middle point of the neural arch of the typical vertebra, represented by the spinous process.
- palatine spines [TA] the longitudinal ridges along the palatine grooves on the inferior surface of the palatine process of the maxilla. SYN: spinae palatinae [TA].
- poker s. stiff s. resulting from widespread joint immobility or overwhelming muscle spasm as might be evoked by an osteomyelitis of a vertebra or a rheumatoid spondylitis.
- posterior inferior iliac s. [TA] s. at the inferior end of the posterior border of the ilium between the posterior superior iliac s. and the greater sciatic notch; it forms the upper margin of the latter. SYN: spina iliaca posterior inferior [TA].
- posterior nasal s. of horizontal plate of palatine bone [TA] the sharp posterior extremity of the nasal crest of the hard palate. SYN: spina nasalis posterior laminae horizontalis ossis palatini [TA], posterior palatine s..
- posterior superior iliac s. [TA] the posterior extremity of the iliac crest, the uppermost point of attachment of the sacrotuberous and posterior sacroiliac ligaments; a readily apparent dimple occurs in the skin overlying the posterior superior iliac s. which is clinically useful as an indication of the level of the S2 vertebra, the level of the inferior limit of the subarachnoid space. SYN: spina iliaca posterior superior [TA].
- s. of scapula [TA] the prominent triangular ridge on the dorsal aspect of the scapula, providing attachment for the trapezius and deltoid muscles and separating the supra- and infraspinous fossae; the acromion is a lateral extension from the s.. SYN: spina scapulae [TA].
- s. of sphenoid bone [TA] a posterior and downward projection from the greater wing of the sphenoid bone on either side, located posterolateral to the foramen spinosum, so named for its proximity to the sphenoidal s.; gives attachment to the sphenomandibular ligament. SYN: processus spinosus [TA], spina ossis sphenoidalis [TA], alar s., angular s., sphenoidal s., spina angularis, spinous process of sphenoid.
- suprameatal s. [TA] small bony prominence anterior to the supramastoid pit at the posterosuperior margin of the bony external acoustic meatus. SYN: spina suprameatalis, Henle s., meatal s., spina meatus, spina suprameatica.
- thoracic s. the thoracic region of the vertebral column; the thoracic vertebrae [T1–T12] as a whole; that part of the vertebral column which enters into the formation of the thorax.
- trochlear s. [TA] a spicule of bone arising from the edge of the trochlear fovea, giving attachment to the pulley of the superior oblique muscle of the eyeball. SYN: spina trochlearis [TA].
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spine 'spīn n
1) SPINAL COLUMN
2) a pointed prominence or process (as on a bone)
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n.
1. a sharp process of a bone.
• spinal adj.
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(spīn) 1. spina (def. 1). 2. columna vertebralis. 3. bar (def. 6).Medical dictionary. 2011.