THE VERTEBRAL COLUMN

The vertebral column, also known as the backbone or spinal column, is the central supporting structure of the skeleton. The vertebral column forms the backbone of vertebrate animals and protects the spinal cord. It is made up of five groups of bones called the vertebrae (singular: vertebra) in mammals. In humans, it consists of 33 vertebrae, in rabbit it consists of 46 vertebrae. The vertebrae are held one to the others with strong ligaments having compressible cartilage pads called intervertebral discs between consecutive vertebrae.

In mammals, the five different vertebrae are:

1. Cervical vertebrae – found in the neck region.
2. Thoracic vertebrae – found in the chest region.
3. Lumber vertebrae – found in the upper abdomen.
4. Sacral vertebrae – found in the lower abdomen
5. Caudal vertebrae – found in the tail region.

Features of a Typical Vertebra

All vertebrae even though they have different functions have certain features in common.

A typical vertebra possesses the following features:

1. Neural canal: This is for the passage of the spinal cord.
2. Neural spine: This projects upwards dorsally for the attachment of muscles.
3. Transverse processes: They project from the sides of each vertebra for the attachment of muscles and ligaments.
4. Centrum: It is a solid piece of bone below the neural canal.
5. Facet: This is a small, smooth, flat or slight depressed area on a bone that is usually a point of contact with another bone.
6. Zygapophysis: These are articular surfaces for the articulation of successive vertebrae. They are grouped into two parts – the pre- zygapophyses facing inwards and upwards and post-zygapophyses facing outward and downward.