The spine, or vertebral column, is made up of 26 bones, the majority of which are the vertebrae. The cocyx and sacrum are the other two bones; these are the most inferior bones of the spine and are actually fusions of vertebrae. The vertebrae protect the spinal cord and aid in maintaining an upright position. The three regions of the vertebral column are the cervical (kneck region), thoracic (thorax section, ach connecting to ribs), and the lumbar section (lower back).
The five most superior vertebrae, in the posterior kneck. The cervical vertebrae are the smallest and most fragile. The first cervicle vertebrae is known as Atlas (C1) because it holds up the head. The second is Axis (C2), so named because during development, it fuses with Atlas and its dens becomes a point around which Atlas can pivot.
The vertabrae in the thorax region, each connected to one or more ribs. A trick is to imagine the a giraffes face and kneck when observing a thoracic vertebrae.
The seven most inferior vertebrae. The lumbar vertebrae have the largest, most sturdy body. Herniated discs (tearing of the intervertebral dics) are most common in this region because of the thickness of lumbar vertebrae.
Each of these regions is curved in a specific manner to aid in balance, support, and posture.
Vertebrae are separated by intervertebral discs, cartilagenous joints, primarily made up of water, that soften the contact between vertebrae as well as hold them together. The disc is made up of two primary parts; the annulus fibrosis and the nucleus pulposus. The nucleus acts as a shock absorber. With the exeption of the C1 to C2 joint, all vertebrae have intervertebral discs.
Common Vertebral Disorders
- Kyphosis - a condition associated with a rounded or "hunched" back.
- Lordosis - a forward projection causing the abdomen to project outward.
- Scoliosis - an abnormal curvature of the spine causing a swayed apperance. This disorder is the most common and is associated with an "S" shape.