Word Finder - vertebrae

definition

Any of the small bones which make up the backbone.

The term " lumbar " vertebrae is inapplicable to birds.

In many lizards the muscles of the segments of the tail are so loosely connected and the vertebrae are so weak that the tail easily breaks off.

These are a chain of small bones belonging to the first four vertebrae, which are much modified, and connecting the air-bladder with the auditory organs.

With few exceptions they have amphicoelous vertebrae, the parietal bones remain separate and they have no eyelids, with very few exceptions.

The vertebrae of the neck unite by nearly flat surfaces, the humerus has lost the foramen, or perforation, at the lower end, and the third trochanter to the femur may also be wanting.

The first and second vertebrae each have a pair of long, movable ribs.

The last I to 5 of these vertebrae have movable ribs which do not reach the sternum, and are called cervico-dorsals.

The last six or seven caudal vertebrae coalesce into the pygostyle, an upright blade which carries the rectrices.

Caudal vertebrae more than thirteen, without a pygostyle, but with about twelve pairs of rectrices.

On the other hand the Odontotormae, as exemplified in Ichthyornis, having the primitive biconcave vertebrae, yet possessed the highly specialized feature of teeth in distinct sockets.

Dorso-lumbar vertebrae never fewer than twentytwo, usually twenty-three in the existing species.

Dorsal and lumbar vertebrae together always nineteen, though the former may vary from twelve to fifteen.

The lowest coccygeal vertebrae of man remain as a rudimentary tail.

In 1966 she had three vertebrae fused in her back.

The least specialized genus is Zapus, containing the jumping-mice of North America, with one outlying Siberian species, in which the five metatarsals are free, as are also the cervical vertebrae, the small upper premolar being retained.

Some of the cervical vertebrae are also united in at least the better-known genera.

The tail is generally very short, and its basal vertebrae are often fused with the sacrum.

The dorsal and lumbar vertebrae are very numerous, 28 to 30, of which 21 or 22 bear ribs.

Although toad-like it is not really related to the toads proper, but belongs to the family Discoglossidae, characterized by a circular, adherent tongue, teeth in the upper jaw and on the palate, short but distinct ribs on the anterior vertebrae, and convex-concave vertebrae.

Titanotherium, of the Oligocene of the Dakotas and neighbouring districts, was a huge beast, with the hinder upper premolars similar in character to the molars, a pair of horn-cores, arising from the maxilla, overhanging the nose-cavity, four front and three hind toes, only twenty dorso-lumbar vertebrae, and an almost continuous and unbroken series of teeth, in which the canines are short; the dental formula being i.

The neck is long and curved, and its vertebrae are remarkable for the position of the canal for the transmission of the vertebral artery, which does not perforate the transverse process, but passes obliquely through the anterior part of the pedicle of the arch.

The vertebrae are C. 7.

In the vertebrae of the neck the distinctive cameloid characters had already made their appearance.

Unlike the giraffe, the length of the limbs is due to the elongation of their upper segments, and that of the neck to the lengthening of only the hinder vertebrae.

It may be added that in the Oreodontidae the vertebral artery pierces the transverse processes of the cervical vertebrae in the normal manner.

The last dozen vertebrae each carry a pair of well-developed typical quills.

However, the fact that various recent birds possess the same kind of caudal skeleton, likewise without a pygostyle, although reduced to at least 13 vertebrae, shows that the two terms do not express a fundamental difference.

Vertebral column composed of about 50 vertebrae, viz.

The number of vertebrae is - in the cervical region 7, dorsal 13, lumbar 6, sacral 2, caudal varying according to the length of the tail, but generally from 21 to 25.

In tracing the osteological characters of apes and man through this series, the general system of the skeletons, and the close correspondence in number and arrangement of vertebrae and ribs, as well as in the teeth, go far towards justifying the opinion of hereditary connexion.

To it contributes the balance of the skull on the cervical vertebrae, while the human form of the pelvis provides the necessary support to the intestines in the standing attitude.

There are no teeth on the palate; pyloric appendages exist in great numbers; the vertebrae number fifty-three.

The presence of only seven vertebrae in the neck is a very constant feature among mammals; the exceptions being very few.

A similar constitution of the body is more clearly seen in the Chaetopod worms. In the Vertebrata also a repetition of units of structure (myotomes, vertebrae, &c.) - which is essentially of the same nature as the repetition in Arthropods and Chaetopods, but in many respects subject to peculiar developments - is observed.

The vertebral column consists of seven cervical, eighteen dorsal, six lumbar, five sacral, and fifteen to eighteen caudal vertebrae.

There may be nineteen rib-bearing vertebrae, in which case five only will be reckoned as belonging to the lumbar series.

The bodies of the cervical vertebrae are elongated, strongly keeled, and markedly opisthocoelous, or concave behind and convex in front.

To these is attached the powerful elastic ligament (ligamentum nuchae, or " paxwax ") which, passing forwards in the middle line of the neck above the neural arches of the cervical vertebrae - to which it is also connected - is attached to the occiput and supports the weight of the head.

The transverse processes of the lumbar vertebrae are long, flattened, and project horizontally outwards or slightly forward from the arch.

The caudal vertebrae, except those quite at the base, are slender and cylindrical, without processes and without chevron bones beneath.

Caudal vertebrae fused into a urostyle or coccyx.

The Discoglossidae are noteworthy for the presence of short ribs to some of the vertebrae, and in some other points also they approach the tailed batrachians; they may be safely regarded as, on the whole, the most generalized of known Ecaudata.

In the earliest forms of this order, the Stegocephalia, we meet with considerable variety in the constitution of the vertebrae, and these modifications have been used for their classification.

In the Ecaudata, the vertebrae of the trunk are formed on two different plans.

In some the notochord remains for a long time exposed along the ventral surface, and, owing to the absence of cartilaginous formation around it, disappears without ever becoming invested otherwise than by a thin elastic membrane; it can be easily stripped off below the vertebrae in larval specimens on the point of metamorphosing.

In the Caudata and Apoda, cartilage often persists between the vertebrae; this cartilage may become imperfectly separated into a cup-and-ball portion, the cup belonging to the posterior end of the vertebra.

Amphicoelous (bi-concave) vertebrae are found in the Apoda and in some of the Caudata; opisthocoelous (convexo-concave) vertebrae in the higher Caudata and in the lower Ecaudata; whilst the great majority of the Ecaudata have procoelous (concavo-convex) vertebrae.

In accordance with the saltatorial habits of the members of this order, the vertebrae, which number from 40 to 60 in the Caudata, to upwards of in the Apoda, have become reduced to Io as the normal number, viz., eight praecaudal, one sacral and an elongate coccyx or urostyle, formed by coalescence of at least two vertebrae.

It is also possible to break the vertebrae in the neck without causing any injury to the spinal cord.

The device performs a gentle and repeated circular motion, which moves the vertebrae of the lower back and the pelvic area.