Spines


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Spines

 

in animals, hard thorny formations, usually projecting above the body surface, and having a chiefly protective function.

In sponges the spines, or spicules, are uni-, tri-, tetra-, or multi-radiate formations of lime carbonate or silica that form the internal skeleton. In most echinoderms, the spines are external lime formations that are particularly diverse in sea urchins. In bony fish, the spines, or spikes, are hard, unsegmented, bony rays located mainly along the front edge of the fins; they are especially numerous on the dorsal fin of acanthopterygian fish (perch, ruff). In some mammals the horny spines are thick, modified hairs that come to a point. Examples among the monotremes are the echnidas— Tachyglossus and Zaglossus; among the insectivores, the tenrecs and hedgehogs; among the rodents, the porcupine.

References in periodicals archive ?
Doing so allowed them to reduce the number of spines on Pufferfish, as well as loosen the restriction on where the spines appear on the Pufferfish.
The authors of this article believe that it is more appropriate to use the name 'infratemporal spine' because of its position (located on the edge of the infratemporal region) and also its shape, which, in this sample, shows structures similar to bony spines with sharp edges (pyramidal and spiniform laminar).
This "text neck" tendency if uncorrected can lead to frequent neck, head and back pains or damage to the spine. It also weakens the respiratory and circulatory systems and induces poor emotional health as well.
Irregular urchins have several morphologically distinct spine types, depending on where those spines are located on the urchin test.
The sex, disc width ([W.sub.D]; to the nearest mm), number of caudal spines, and length of each spine (to the nearest ram) was determined for each ray.
When validated, the model will enable companies to design and test implants much faster, as small modifications to the device can be tested virtually--forgoing expensive and time-consuming work on cadaver spines. Already, one bioengineering company working with the Purdue researchers has used the model to speed development of a new device.
Abnormality resulting from an injury on the pectoral spines in Synodontis species has not been reported.
Anatomically, weak abdominal or tight psoas muscles are indirect contributors; faults in technique, such as extending the pelvis to improve hip turn-out, executing arabesques through the extension of the lumbar spine, and poor lifting technique in male dancers, may also contribute.
We used a boreal finch, the Red Crossbill (Loxia curvirostra), in experiments to test the effect of spines on foraging rates, because crossbills forage on seeds in both closed and open cones (Benkman 1987a, b, Benkman and Lindholm 1991).
Tweezing alone removed 76 percent of the spines. It was also the fastest method, particularly if the spines were in clumps.
Urobatis halleri, like other stingrays, utilize their spines in defense against predators and occasionally on humans, who inadvertently step on them (e.g., Gudger 1932, 1946; Campbell 1951; Russell 1953).