Vertebral Column

Vertebral column also known as spinal column, backbone or spine, It is formed by 26 serially arranged bones called vertebrae and is dorsally placed. It makes up about 2/5 of the total weight of an individual (Average length is 71cm in adult male and 61cm in adult female). It extends from the base of skull and constitute the main framework of the trunk. During early development, the total number of vertebrae is 33 where as in an adult vertebral column contains 26 vertebrae.

The cervical, thoracic and lumbar vertebrae are movable but the sacrum and coccyx are not.

1.0Intervertebral disc

Intervertebral discs are present between two adjacent vertebrae from second cervical vertebrae to sacrum. It raises the height of vertebral column by 25%. Each intervertebral disc consists of outer fibrocartilage known as annulus fibrosus and inner soft substance is known as nucleus pulposus. These pads are called intervertebral disc.

2.0Normal curves of the vertebral column

The vertebral column appears straight, when viwed from the anterior posterior axis. When observed from the side, Vertebral Column shows four slight bends called normal curves. The cervical and lumbar curves bulge out i.e. convex, on the other hand, the thoracic and sacral curves cupp in i.e. concave. These curves increases the strength of vertebral column, maintains balance in upright position and protects the vertebrae from any damage like fracture.

3.0Parts of a typical vertebrae

VERTEBRA

4.0Vertebral Regions

Cervical vertebrae (C₁-C₇)

They are the smallest in size, present in the neck region. In all mammals, the first seven vertebrae are called cervical vertebrae. The first vertebrae is the ‘altas’ and the second in known as axis,

Altas is a ring of bone which articulate with the occipital condyles of the occipital bone and form the paired atlanto-occipital joints. This joint permits the nodding movement of the head i.e. to signify ‘yes’.

The Second cervical vertebra called axis has a peg like process called odontoid process articulates with the atlas. This joint is known as atlantoaxial joint. It allows side to side movement of the head i.e. to signify ‘no’.

Thoracic vertebrae (T₁-T₁₂)

These vertebrae are located in the chest region. They are larger and stronger than cervical vertebrae. Thoracic vertebrae are 12 in number and they articulate with 12 pairs of ribs. The articulation between the thoracic vertebrae and ribs is known as vertebrocostal joints.

Lumbar vertebrae (L₁-L₅)

These are the strongest, largest and thickest vertebrae present in the vertebral column. They bear the body weight.

Sacral vertebrae

Five sacral bones fuse to form a triangular bone called sacrum. It forms a strong foundation for the pelvic girdle.

Coccyx

Like sacrum, coccyx is also a triangular bone formed by fusion of four coccygeal vertebrae. It forms a small vestigial tail at the base of sacrum.

5.0Functions of vertebrae column

• It encloses and protects the spinal cord which travels within the spinal canal formed by a central hole present with in each vertebra.
• It supports the head and carry the weight of the body prior to pelvies.
• It provides the point of articulation to ribs and muscles at the back.
• It plays a vital role in both posture and movement of the body.