A normal spine curves in an S shape, with the cervical spine curving forwards, the thoracic section curving backwards, the lumbar forwards, and the sacrum curving backwards. The story character the Hunchback of Notre Dame suffered from kyphosis excessive curving of the spine.
The backbone, otherwise known as the spine, extends from the base of the skull down to the hips.
The backbone is not a single bone, but a column of drum-shaped bones called vertebrae (singular, vertebra).
There are 33 vertebrae altogether, although some of these fuse or join as the body grows.
Each vertebra is linked to the next by small facet joints, which arc like tiny ball-and-socket joints.
The vertebrae are separated by discs of rubbery material called cartilage. These cushion the bones when you run and jump.
The bones of the spine are divided into five groups from top to bottom. These are the cervical (7 bones), the thoracic (12 bones), the lumbar (5 bones), the sacrum (5 bones fused together), and the coccyx (4 bones fused together). Lumbar spine
The cervical spine is the vertebrae of the neck. The thoracic spine is the back of the chest, Sacrum The backbone is not straight – instead, its 33 vertebrae curve into an S-shape.
On the back of each vertebra is a bridge called the spinal process. The bridges on each bone link together to form a tube which holds the spinal cord, the body’s central bundle of nerves.