Vertebral column Supports SkullPectoral girdleUpper limbThoracic cage

ProtectsSpinal cord and the spinal nerve roots

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Composed of 33 vertebrae

7 cervical12 thoracic5 lumbar5 sacral4 coccygeal

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Because it is segmented, made of vertebrae, pads of fibrocartilage, the intervertebral discs join each vertebra

The intervertebral discs form about 1/4th of the length of column

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Typical vertebra consists of rounded body, anteriorly

Vertebral arch posteriorly.These enclose vertebral foramen, through

which spinal cord runs.Arch consists of 7 processesSpinous process(1)Transverse process(2)Articular processes(4)

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Joints Between Two Vertebral Bodies

Upper and lower surfaces of the bodies of adjacent vertebrae by thin plates of hyaline cartilage.

Sandwiched between the plates of hyaline cartilage is an intervertebral disc of fibrocartilage.

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Each disc has a peripheral

part, anulus fibrosus (consisting of concentric layers of collagen fibers), and

a central part the nucleus pulposus (ovoid mass of gelatinous material collagen fibers and a few cartilage cells).

A sudden increase in compression load on vertebral column causes nucleus pulposus to thrust outward, where it may press on the spinal cord or the nerve roots causing pain.

This mainly happens with advancing age collagen fibers of the anulus degenrates and as a result the anulus cannot contain the nucleus pulposus under stress.

The 1st, 2nd cervical verterbrae, sacrum, and coccyx lacks intervertebral discs

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Joints between two vertebral arches

Synocial joints between the supeerior and inferior articular processes of adjacent vertebrae.

The articular facets are covered by hyaline cartilage and sorrounded by a capsular ligament.

Supraspinous ligament,interspinous ligament, intertransverse ligaments and ligamentum flavum helps in stabilizing the joints

In cervical region, the supraspinous and interspinous ligaments are greatly thickened to form strong ligamentum nuchae,which extends from 7th cervical spine to the external occipital protuberance

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Atlanto-Occipital joints

Synovial joints Between occipital condyles(present on

either side of foramen magnum) and facets on the superior surfaces of the lateral masses of the atlas

Capable of flexion , extension and lateral flexion. They do not rotate

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Atlanto-Axial joints3 synovial joints; 1 between odontoid process and the

anterior arch of atlas2 between the lateral masses of the bones

Extensive rotation of the atlas and thus the head on the axis.

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Curves of verterbral column In fetus, the vertebral column has one

continuous posterior convexity. In adult, the vertebral column exibitsCervical , posterior concavityThoracic, posterior convexityLumbar, posterior concavity and sacral, posterior convexity

In old age, the intervetebral discs atropygradual return of vertebral column to continuous

posterior convexity15

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