Vertebral Column - Structure, Functions, Conditions Affecting Adults
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Vertebral Column - The Structural Body Support

Dr.Surya Rao Poodipeddi profile Authored by Dr.Surya Rao Poodipeddi on 28 Feb 2014 - 18:11.
The vertebral column is one of the most important components in the architecture of the body, providing strength and support. Without the vertebral column, it would be impossible to hold an upright position or stand. In addition to the structural support, it provides flexibility and motion. The vertebral column plays a unique role in our body's movement and function by protecting the spinal cord, a column of nerves which is a continuation of the brain.
The human vertebral column, also called spinal column (the spine) is a masterpiece of creation designed to house the vital spinal cord and allow a range of movements in all directions.
It is a flexuous and flexible column formed with the combination of several pieces of individual bones called vertebrae. Somewhat "S" shaped in appearance, the vertebral column has 33 vertebrae placed one over the other from top to bottom grouped under different names in accordance with the regions they occupy in the body in the order of cervical, thoracic, lumbar, sacral and coccygeal.
The cervical portion of the vertebral column is situated in the neck and consists of seven vertebrae. Though the number of vertebrae in each region may sometimes increase or decrease, those in the cervical region very rarely decrease or increase. The top two vertebrae in the cervical portion called Atlas and Axis are almost fixed to the base of the big opening called foramen magnum through which the spinal cord descends down.
The rest of the vertebrae are situated one over the other each separated from the other by a cartilaginous structure called the disc. The disks prevent the vertebrae from rubbing each other and act like a cushion providing free mobility to the entire cervical column enabling frontward, backwards, sideways and rotatory movements of the head over the neck.
The thoracic portion of the vertebral column consists of 12 vertebrae. They help in the formation of the bony cage protecting the lungs and the heart. The bony cage is formed through 12 pairs of ribs, seven of which are true ribs, three are false ribs and two are floating ribs. Each rib joins the corresponding side of the vertebra behind and the breast bone or the sternum in front (the false ribs joining through a cartilage) except the last two pairs which are floating. The cervical portion of the spinal cord continues its decent through the central space of all the vertebrae.
The lumbar portion of the vertebral column consists of five vertebrae called the lumbar vertebrae which are situated behind the abdomen. Their central spaces provide pathway for the lumbar portion of the spinal cord.
The last lumbar vertebra joins a combination of five sacral vertebrae which are fixed and not mobile. This combined portion is called the sacrum. Similarly the sacrum is joined to a portion of the vertebral column called coccyx which is a fusion of four vertebrae. The tip of this bone can be felt with a finger at the bottom of the vertebral column.
To sum up, the entire vertebral column consists of seven cervical vertebrae, 12 thoracic vertebrae and five lumbar vertebrae all of which are mobile with wide range of movements and the sacrum which is fusion of five vertebra and coccyx consisting of four vertebrae joined together. These two portions are fixed and hence are not mobile.
A typical vertebra consists of two essential parts an anterior (front portion) called the body and a posterior part (the back portion) called the vertebral or neural arch. These two portions enclose a foramen called the vertebral foramen. The vertebral arch consists of a pair of pedicles and a pair of laminae and supports seven processes namely four articular (meant for articulating with the vertebra above and below), two transverse processes and one spinous process.
When the vertebrae articulates with each other, the bodies form a strong pillar which supports the head and the trunk. The vertebral foramina constitute a canal for the protection and accommodation of the spinal cord called medulla spinalis. Between every pair of vertebrae are two openings the intervertebral foraminae one on each side, meant for the transmission of spinal nerves and blood vessels.
The body of a vertebra is the largest part and is more or less cylindrical in shape. Its upper and lower surfaces are flattened and give attachment to the vertebra above and below, with the help of intervertebral fibro-cartilagenous tissue providing a rim at its circumference.
In front, the vertebra is convex in shape from side to side and concave from above downwards. Behind it is flat from above downwards and marginally concave from side to side. The front portion has a few small apertures for the passage of vessels for nutrition. The back portion has a fairly large opening for the exit of the vertebral veins.
The pedicles of the vertebra are two short processes which project backwards one on each side, from upper portion of the body at its junction between posterior and lateral surfaces. The concavities above and below these pedicles form the vertebral notches which help in the formation of the intervertebral foramen.
From the pedicles two broad plates directed backward and inwards project out called the laminae. The laminae fuse in the middle line posteriorly (backwards) completing the posterior boundary of the vertebral foramen. The upper borders and the front surfaces are rough for the attachment of a ligament called ligamenta flava.
The spinous processes of the vertebra are directed backwards and downwards from the junction of the laminae and serves for the attachment of the muscles and ligaments. The articular processes two above and two below spring from the junctions of the pedicles and the laminae. They are coated with hyaline cartilages for easy articulation with each vertebra.
The transverse processes, two in number, projecting one at either side serve for the attachment of muscles and ligaments.
Conditions affecting the vertebral column:
There are many conditions that affect the vertebral column. Ideally, they are best divided into two groups namely those affecting the vertebral column and those affecting the spinal cord. We will limit our description only to those affecting the vertebral column since the spinal cord will be described in a separate article.
Conditions affecting the vertebral column can be broadly divided into congenital and acquired. The congenital conditions affect mainly the pediatric population.
At birth the spine may be affected by congenital malformations. Modern advances in medicine make it possible to diagnose these abnormalities "in utero" .i.e. when the baby is still in the Womb. Congenital abnormalities can change the development of the individual vertebrae leading to deformities like scoliosis. Many of these deformities may need early surgical interventions. Infantile scoliosis is diagnosed before the child starts walking and surprisingly resolves by itself, reasons being unknown.
Idiopathic (unknown cause) scoliosis which normally develops after the age of three, is termed juvenile scoliosis. The prognosis in these cases is very poor.
Conditions affecting the adolescents and adults:
Scoliosis may also affect the adolescents. Another deformity in adolescents is Kyphosis and Kyphoscoliosis. Postural round back is a common condition though it may not require aggressive treatment.
 The commonest condition affecting the lumbar vertebra is Spondylolisthesis which can occur due to an accident or dysplasia (abnormal formation of the fifth lumbar and the 1st sacral vertebrae). In majority of the cases this is more a condition than a problem as this occurs due to stress and overuse of the vertebrae like in gymnastics, football or weightlifting.
Once the spine has stopped growing, spinal deformities usually result due to injuries, degeneration, tumors or a gradual progression of a problem present since childhood.
One of the most common sites affecting the vertebral column is the intervertebral disc. The disc which acts as a stabilizer between the vertebra of the spine and serves as a shock absorber, can be affected in several ways namely collapse of the disc, herniation (bulging) of the disc and tear or fragmentation of a disc.
Degenerative disorders of the vertebral column include changes occurring in the soft tissues like disc, ligaments and muscles which lose their elasticity and capacity to stabilize. As age advances, the bones themselves may begin to loose minerals and become fragile like in a condition called Osteoporosis.
Other conditions commonly affecting the vertebral column including the intervertebral disc are, Spinal Stenosis  (mainly due to prolapsed intervertebral disc), Ankylosing spondylitis, Bulging disc, degenerative diseases, injuries to the vertebrae including spinal fractures and osteoporosis occurring mainly in women after menopause.
Treatment depends on the cause and may involve physiotherapy, medication and surgical interventions depending on the condition and cause.
*Disclaimer: This is not medical advice. The content is for educational purposes only. Please contact your doctor for any health care issues.