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see spinal columnspinal column,
bony column forming the main structural support of the skeleton of humans and other vertebrates, also known as the vertebral column or backbone. It consists of segments known as vertebrae linked by intervertebral disks and held together by ligaments.
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The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



in terrestrial vertebrate animals and in man, one or several vertebrae that provide a strong connection between the iliac bones of the pelvis and the axial skeleton. The sacrum was formed as a result of the progressive development of the posterior extremities and their important role in locomotion. True sacral vertebrae (on which, if only in the embryo, there are sacral ribs that subsequently grow together with the transverse processes of the vertebrae) are distinguished from those that enter into the composition of the sacrum secondarily in order to reinforce it.

Present-day amphibians have one sacral vertebra, and reptiles have two (fossil forms often had more). In birds with two true sacral vertebrae, the anterior caudal, all the lumbar, and one or two of the last thoracic vertebrae are grown together to form a single bone, the synsacrum, out of ten or 12 vertebrae. In mammals, up to ten vertebrae are grown together in the sacrum; only one or two are true sacral vertebrae, and the rest are the anterior caudal vertebrae. When there is secondary disappearance of the posterior extremities (for example, in snakes and whales), the sacral region of the spine loses its function and is not differentiated.

In humans the sacrum is formed of five vertebrae, which merge in adults into a single sacral bone (os sacrum), which posteriorly closes the pelvic girdle.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


A triangular bone, consisting in humans of five fused vertebrae, located below the last lumbar vertebra, above the coccyx, and between the hipbones.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


1. (in man) the large wedge-shaped bone, consisting of five fused vertebrae, in the lower part of the back
2. the corresponding part in some other vertebrates
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
No (n = 72) % Localization by the regions Sacral region 41 74.5 Trochanteric 12 21.8 Ischia 11 20 Femoral 3 5.4 Occipital 2 3.6 Malleolar 2 3.6 Calcaneal 1 1.8 Surgical methods Musculocutaneous flaps 20 36.3 Cutaneous local flaps 18 32.7 Direct closure 12 21.8 Cutaneous grafts 12 21.8 Fasciocutaneous flaps TFL * 10 18.1 * TFL-tensor fascia lata.
The results of our study, based on NOC indicators, suggest that the sacral region and the scapula regions are susceptible areas, since they showed high temperatures.
(1979) reported, by radiography of the human spine, that from 8 weeks the longest vertebral column belonged to the thoracic region followed by the lumbar, cervical, and sacral regions. Muller & O'Rahilly (1986) by using serial sections of human embryos, documented that the relative length of the vertebral bodies of the cervical and coccygeal regions decreased, the thoracic and lumbar regions increased, and the sacral region was more or less constant during embryonic development.
MRI revealed a thick-walled cystic space occupying lesion noted in the sacral region with intrapelvic components.
Location of myelomeningoceles of the 38 patients in our study, 4 were noted in the cervical region, 2 in the dorsal region, 5 in the lumbar region, 7 in the sacral region, 20 in lumbosacral region and 2 in dorsal region.
MRI OF PELVIS (PLAIN AND CONTRAST): Shows 20 x10 x 9.2cm sized (CCx AP x Tr), large, well marginated, lobulated, heterogeneously enhancing mass lesion with central non-enhancing / necrotic area seen in per- sacral region / pelvis with extent as described above.
Common sites are the tip of nose (due to the pressure of the endotracheal tube or nasogastric tube) and pressure areas in the sacral region with the patient in the reverse Trendelenberg position.
This neural tube defect may occur anywhere along the vertebral column, but lumbar and sacral region are more common.
The work is the first to analyze elements of the cervical, thoracic, lumbar, and sacral regions of the vertebral column in Au.
It is used as an adjunct to fusion to treat degenerative slipped discs (spondylolisthesis) in the thoracic, lumbar or sacral regions when there is evidence of resulting neurologic impairment or in the case of a previous failed fusion (pseudarthrosis).
Aplastic or hypoplastic vertebrae, hemivertebrae and butterfly vertebrae may be demonstrated at the thoracic, lumbar or sacral regions. There may be marked stenosis or even interruption of the spinal canal at the level of the malformation, and the osseous canal can resemble an hour-glass shape.
According to these standards, the neurologic level of injury is defined as "the most caudal (lowest) segment of the spinal cord with normal sensory and motor function on both sides of the body." The generic way that level of injury is described is by the classifications "quadriplegia or tetraplegia," referring to injuries of the cervical regions, and "paraplegia," referring to injuries of the thoracic, lumbar, or sacral regions.