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Related to rachis: petiolule


1. a thornlike process or projection; called also acantha and spina.
2. the rigid bony structure in the midline of the back, composed of the vertebrae; called also backbone, spinal column, and vertebral column.

The spinal column is the axis of the skeleton; the skull and limbs are in a sense appendages. The vertebrae also provide the protective bony corridor (spinal canal) through which the spinal cord passes; they can move to a certain extent and so give flexibility to the spine, allowing it to bend forward, sideways and, to a lesser extent, backward. In the areas of the neck and lower back, the spine also can pivot, which permits the turning of the head and torso.

There are usually 24 movable vertebrae and nine that are fused together. The topmost are the seven cervical vertebrae, which form the back of the neck, supporting the skull. The head turns from side to side by means of a pivotal motion between the two highest vertebrae. Below these are the 12 thoracic vertebrae, the supports on which the ribs are hinged, and then the five lumbar vertebrae, the largest movable vertebrae (the cervical are the smallest). Below the lumbar vertebrae, the spine terminates with two groups of vertebrae fused into single bones: the sacrum, composed of five vertebrae, and the coccyx, composed of four vertebrae. Viewed from the side of the body, the spine has the shape of a gentle double S curve.
Malformations of the Spine. Of the various types of spinal malformations, some are congenital and others the result of postural defects or injuries. spina bifida is congenital. kyphosis may occasionally be congenital but is more often caused by one of the diseases that attack the structure of the bones. The most common of these is pott's disease, or tuberculosis affecting the vertebrae and soft tissues of the spine. Another is osteitis deformans, a type of bone inflammation in which parts of the bone are replaced by softer tissue. scoliosis is a curvature of the spine toward one side.
cervical spine that portion of the spine comprising the cervical vertebrae.
lumbar spine that portion of the spine comprising the lumbar vertebrae.
thoracic spine that part of the spine comprising the thoracic vertebrae.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ver·te·bral col·umn

the series of vertebrae that extend from the cranium to the coccyx, providing support and forming a flexible bony case for the spinal cord.
Farlex Partner Medical Dictionary © Farlex 2012


n. pl. rachises or rachides (răk′ĭ-dēz′, rā′kĭ-)
a. The main stem of an elongated inflorescence, as in a grass.
b. The main axis of a pinnately compound leaf or of a fern frond.
2. The main shaft of a bird's feather, especially the part to which the barbs are attached.
3. The spinal column.

ra′chi·al adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

ver·te·bral col·umn

(vĕr'tĕ-brăl kol'ŭm) [TA]
The series of vertebrae that extend from the cranium to the coccyx, providing support and forming a flexible bony case for the spinal cord.
Synonym(s): columna vertebralis [TA] , backbone, rachis, spina, spinal column, spine (2) .
Medical Dictionary for the Health Professions and Nursing © Farlex 2012




any central axis, particularly that of a feather.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
Antennal flagellum weakly crenulate on posterior surface, without deep concavity between flagellomeres; mandible distinctly broad apically; posterior hypostomal carina with strong tooth; protibial spur with apex long, about three-fourths of malus length, with a distinct row of 10 elongate branches (not including apical portion of rachis); S3-S4 with distal margins gently convex; S5 with midapical row of spines straight, not medially projecting (Ecuador: Napo).
Number of leaflets-NLL showed positive correlation with girth (G=0.0564; P=0.0627), sex ratio-SR (G=0.3258; P=0.0903), number of leaves-NL (G=0.1278; P=0.0031), petiole width-PW (G=0.1195; P=0.1770) petiole depth-PD (G=0.0755; P=0.1494), rachis length-RL (G=0.5757; P=0.4434), leaflet width-LLW (G=0.0492; P=-0.0233), leaf area-LA (G=0.4748; P=0.4672), leaf dry weight-LDW (G=0.2926; P=0.2892), total leaf dry weight-TLDW (G=0.3129; P=0.3010), vegetative dry matter-VDM (G=0.1337; P=0.1868), bunch number-BN (G=0.2230; P=0.1694), average bunch weight-ABW (G=0.1137; P=0.0758), bunch dry weight-BDW (G=0.1899; P=0.1436), total dry matter-TDM (G=0.2980; P=0.2928), bunch index-BI (G=0.0716; P=-0.0012) and oil to bunch ratio (G=0.1627; P=0.0726).
As for the studied variables: berry firmness, weight loss, soluble solids, rachis dry matter, and berry dry matter were statistically significant (Table 3).
3.5 mm diam.; petiole 7-23 mm long, smaller than the rachis; 1 extrafloral nectary, green-vinaceous, sessile, pyramidal, 1-3 mm long, located on the rachis, between the proximal pair of leaflets; rachis 13-15 mm long; leaflets discolorous, 2 pairs, semisucculent, adaxial surface pilose, abaxial surface tomentose, obovate to elliptic, 21-88 X 9-41 mm, apex rounded, base assimetric, venation penninervous, midrib excentric.
The CNFs from Prunus amygdalus exhibit a typical aspect ratio of CNFs regardless of the cellulose source and the growth conditions [14], especially, when comparing these CNFs with those reported from potato pulp [19], algae [23], peel of prickly pear fruit [24], Opuntia ficus-indica, a cactus, swede root [20], hemp [39], rachis date palm [14], Posidonia oceanica balls [6, 8], and many others types of sources.
Lateral rachis radiography and DXA (Dual Energy X-ray absorptiometry) were performed to exclude vertebral fractures.
In the first case, articulation occurs above the prophyll insertion, which determines the spikelet to fall and the bract, the prophyll and the (highly reduced) hipopodium to remain on the rachis (Cyperus subgen.
Le neuronavigateur acquis par le CHU de Bejaia represente a ce jour le seul equipement sur le territoire national disposant du module rachis.
Tout le monde est expose au risque de tendinite : l'epaule est la localisation la plus frequente ainsi que d'autres articulations, le coude, le genou, le poignet, la cheville ou le rachis.
* If needed, small holes can be punched or burned on each side of the simulated quill (rachis) about half-way up the feather to facilitate a thong to lace the feathers together.