vertebra


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vertebra

 [ver´tĕ-brah] (L.)
any of the separate segments comprising the spine (vertebral column). The vertebrae support the body and provide the protective bony corridor (the spinal or vertebral canal) through which the spinal cord passes. The 33 bones that make up the spine differ considerably in size and structure according to location. There are seven cervical (neck) vertebrae, 12 thoracic (high back), five lumbar (low back), five sacral (near the base of the spine), and four coccygeal (at the base). The five sacral vertebrae are fused to form the sacrum, and the four coccygeal vertebrae are fused to form the coccyx.



The weight-bearing portion of a typical vertebra is the vertebral body, the most forward portion. This is a cylindrical structure that is separated from the vertebral bodies above and below by disks of cartilage and fibrous tissue. These intervertebral disks act as cushions to absorb the mechanical shock of walking, running, and other activity. Sometimes rupture or herniation of a disk may occur (see herniated disk).

A semicircular arch of bone (the vertebral arch) protrudes from the back of each vertebral body, surrounding the spinal cord. Directly in its midline a bony projection, the spinous process, grows backward from the arch. The spinous process can be felt on the back as a hard knob. Three pairs of outgrowths project from the arch. One of these protrudes horizontally on each side and in the thorax connects with the ribs. The remaining two form joints with the vertebrae above and below. The joints permit the spine to bend flexibly. The vertebrae are held firmly in place by a series of strong ligaments.
Structure of vertebrae.
cervical vertebrae the upper seven vertebrae, constituting the skeleton of the neck.
coccygeal vertebrae the lowest segments of the vertebral column, comprising three to five rudimentary vertebrae that form the coccyx.
cranial vertebra the segments of the skull and facial bones, regarded by some as modified vertebrae.
vertebra denta´ta the second cervical vertebra, or axis.
dorsal vertebrae thoracic vertebrae.
false vertebrae those vertebrae that normally fuse with adjoining segments: the sacral and coccygeal vertebrae.
lumbar vertebrae the five vertebrae between the thoracic vertebrae and the sacrum.
vertebra mag´na the sacrum.
odontoid vertebra the second cervical vertebra, or axis.
vertebra pla´na a condition of spondylitis in which the body of the vertebra is reduced to a sclerotic disk.
sacral vertebrae the vertebrae just below the lumbar vertebrae, usually five in number and fused to form the sacrum.
thoracic vertebrae the twelve vertebrae between the cervical and lumbar vertebrae, giving attachment to the ribs and forming part of the posterior wall of the thorax.
true vertebrae those segments of the vertebral column that normally remain unfused throughout life: the cervical, thoracic, and lumbar vertebrae.

ver·te·bra

, gen. and pl.

ver·te·brae

(ver'tĕ-bră, -brē), [TA] Avoid the mispronunciation verte'bra.
One of the segments of the vertebral column; in humans, there are usually 33 vertebrae: seven cervical, twelve thoracic, five lumbar, five sacral (fused into one bone, the sacrum), and four coccygeal (fused into one bone, the coccyx).
[L. joint, fr. verto, to turn]

vertebra

(vûr′tə-brə)
n. pl. verte·brae (-brā′, -brē′) or verte·bras
Any of the bones or cartilaginous segments forming the spinal column.

ver·te·bra

(vĕr'tĕ-bră) [TA]
One of the segments of the spinal column; in human beings there are usually 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused into one bone, the sacrum), and 4 coccygeal (fused into one bone, the coccyx).
[L. joint, fr. verto, to turn]

vertebra

One of the 24 bones of the VERTEBRAL COLUMN.

vertebra

(pl. vertebrae) one of the bony segments of the VERTEBRAL COLUMN.

Vertebra

The bones that make up the back bone (spine).
Mentioned in: Disk Removal

ver·te·bra

(vĕr'tĕ-bră) [TA] Avoid the mispronunciation verte'bra.
One of the segments of vertebral column; in humans, there are usually 33 vertebrae.
[L. joint, fr. verto, to turn]
References in periodicals archive ?
RESUMEN: El objetivo de este estudio fue enfatizar la importancia clinica de la morfometria y los parametros quirurgicos de las vertebras cervicales.
Distribution and incidence of degenerative spine changes in patients with a lumbosacral transitional vertebra. Eur Spine J 1997;6(3):168-72.
Then, angular measurements of the vertebral deviations with the vertical Y axis of each segment of two adjacent vertebrae from the upper limit vertebra to the apical vertebra, referred to as angles R1, R2, R3, etc., were performed.
Among the atypical vertebrae, only the seventh vertebra showed unilateral AFT.
The first, descriptive part of study included morphological analysis of the superior surface of the posterior arch of the atlas vertebra. In accordance with Mitchell's classification [29], atlas vertebrae were classified into three classes: class I--groove for the vertebral artery; class II--vertebrae with an incomplete bony ring with a missing middle part; class III--vertebrae with a complete bony ring which encloses the vertebral artery.
The superior articular facets of the L2 vertebra were faced medially and exhibited prominent mamillary processes.
Mandibular growth changes and maturation of cervical vertebra a longitudinal cephalometric study.
In addition, previous studies showed that vertebra numbers were associated positively with leaner carcass, loin lengths and growth rate, and associated negatively with intramuscular fat content and fat deposition [2,11,20,22].
The Fisher's exact test and the Chi square test of independence were used to determine the effect of gender on the occurrence of vertebral anomalies and the occurrence of clinical signs, and to verify a predisposition of vertebral anomaly for any particular vertebra from C1 to S3 (McDonald, 2008).
Patients took a prone position on a Digital Subtraction Angiography (DSA) table (cervical vertebra took a supine position).
Furthermore, the effect of these changes on load carrying capacity of vertebra was considered.
Lead markers that could be detected in radiographs were attached to the pedicles of each vertebra in the model.