We are standing straight, doing our routine work properly and enjoying our sex life too spine or back plays vital role in all these activities. Let’s have a look at the physical structure of our spine.
The longitudinal row of the disks supports the head and trunk. The intervertebral disks in between the vertebrae separate them from one another yet fasten them together with both the upper and lower surfaces of the bodies by ligaments. These fibrocartilage disks acts as a cushion and shock absorber. Each vertebral disk protrudes two short stalks called "pedicles" which gives rise to two plates like laminae. The laminae fuse posteriorly to become "spinous process." The pedicles, laminae, and spinous process altogether complete a vertebral arch through which the spinal cord passes. Numerous spinal nerves pass through an opening on the surfaces of the vertebral pedicles known as "intervertebral foramina."
The spine is a column made up of three groups of drum-shaped calcified structures called "vertebrae."
The five "lumbar vertebrae" are the lower most vertebrae that support more weight than the vertebrae above them. They have long and strong transverse projections angled backward whereas their short, thick spiny processes are directed horizontally.
The vertebrae in chest region are called "thoracic" vertebrae. These twelve discs, are larger in size than those of the cervical region. The long, pointed spinous processes decending down from the sides joins with ribs. The size of bone increases as moving down from third thoracic vertebra.
The seven bones that form the bony axis of the neck are called "cervical" vertebra. These are the smallest of the all the vertebrae. The "transverse foramina" is a passageway to the arteries leading to the brain. The forked characteristic feature of second till fifth vertebra is rather unique. "Atlas", the first vertebra supports and balances the head. The second vertebra called "axis," bears a tooth-like "odontoid process" on its body which upwardly fixes into the ring of the atlas. When the head is moved, the atlas rotates around the odontoid process.
The tail bone or the lowest part of the vertebral column is called coccyx. When a person sits the pressure of entire body concentrates on the coccyx, and it moves forward, to prevent any shock. Sometimes people suffer fractured or dislocated coccyx because of sitting down with too great force.
The sacrum is a strong large triangular bone at the base of the lower spine. Its broad upper part joins the lowest lumbar vertebrae and its narrow lower part joins the coccyx or "tail bone". The sides are connected to the iliums (pelvic bones). At the time of birth and during early age the five vertebrae of sacrum are separated, but gradually fuse together later sometime around in between the eighteenth and thirtieth years. The sacrum is lodged between the coxal bones of the pelvis and gelled by fibrocartilage at the sacroiliac joints. The weight of the body is transmitted to the legs through the pelvic girdle at these joints.