- It forms the central axis of the skeleton.
- Is centered in the midsagittal plane of the posterior trunk.
FUNCTIONS OF VERTEBRAL COLUMN
- It encloses and protects the spinal cord.
- Acts as support for the trunk.
- It supports the skull superiorly.
- Attachment of ribs laterally.
v In early life the vertebral column normally consists of 33 small, irregular bones which we called vertebrae.
FIVE GROUPS OF VERTEBRAL COLUMN
- 7 Cervical Vertebrae – Upper seven vertebrae that occupy the region of the neck.
- 12 Thoracic Vertebrae – It lies in the dorsal portion of the thorax.
- 5 Lumbar Vertebrae – Occupying the region of the loin or lumbus.
- 5 Sacral Vertebrae
- 3 to 5 Coccygeal Vertebrae
- The 24 segments of the upper three regions remain distinct throughout life and are termed true or movable vertebrae.
- The segments in the two lower regions are called false or fixed vertebrae, because of the change they undergo in adults.
- The sacral segments usually fuse into one bone termed sacrum.
- Coccygeal segments, referred to as coccyx, often fuse into one bone.
- VERTEBRAL CURVATURE
v Vertebral column presents four curves that arch anteriorly and posteriorly from the midaxillary line of the body.
FOUR CURVES OF THE VERTEBRAL COLUMN
- Cervical and Lumbar Curves, which are convex anteriorly and are called Lordotic Curves.
- Thoracic and Pelvic Curves are concave anteriorly and are called Kyphotic curves.
- The Thoracic and Cervical curves merge smoothly while Lumbar and pelvic curves join at an obtuse angle termed the Lumbosacral or sacrovertebral angle.
- The thoracic and pelvic curves are called primary curves, because they are present at birth.
- Cervical and lumbar curves are called secondary or compensatory curves, because they develop after birth.
- Cervical curves, which is the least pronounced of the curves, develops when the child begins to hold the head up at about 3 or 4 months of age and begin to sit alone at about 8 to 9 months of age.
- The lumbar curves develop when the child begins to walk at about 1 ½ years of age.
- The lumbar and pelvic curves are more pronounced in females, causing a more acute angle at the lumbosacral junction.