The Spinal Cord

The spinal cord refers to a long, thin and tube like bundles of nervous tissue and support cells, which extend from the medulla oblongata. The spinal cord and the brain together make up the central nervous system. It starts at the Occipital bone and then extends downwards to the gap between the first and second lumbar vertebrae; however, it does not extend the whole length of the vertebral column. The spinal cord is useful in transmitting neural signals between the brain and the whole body. Moreover, it has neural circuits that are independent in controlling a number of reflexes and central pattern generators. Basically, the spinal cord functions in three ways. It is a centre where certain reflexes are always coordinated. It is a medium for sensory information that moves up the spinal cord. Lastly, it serves as a medium for motor information that goes down the spinal cord.

The spinal cord has millions of nerve fibers that transmit electrical information around the body (Saladin, 2003). Most importantly, spinal nerves in the spinal cord are categorized into four groups that exit at different levels of the spinal cord. The Cervical Nerves (C) in the neck supply feeling and movement to the neck, arms, and upper trunk. The Thoracic Nerves (T) are found on the upper back and involved with supplying the abdomen and trunk. The Lumbar Nerves (L) and Sacral Nerves (S) found in the lower back, supply the sexual organs, the legs, the bowel and the bladder.

In the anatomy of the vertebrate, the sacrum refers to a large and triangular bone found at the bottom of the spine, the upper and back part of the cavity known as pelvic cavity. The upper part bonds with the last lumbar vertebra, and the bottom with the tailbone, also known as the coccyx. The sacrum appears to be curved upon it and tilted forward. It also appears to be concave in shape while facing forwards. The bottom protrudes forward as the sacral promontory internally, and joins with the last lumbar vertebra to form the sacrovertebral angle. Moreover, the central part curves outwards towards the posterior, which allows more room for the pelvic cavity.

The sacrum has several parts. The pelvic surface appears to be concave from up downwards, and also slightly from side to side. The dorsal surface looks convex and narrower than the pelvic bone. Thirdly, the lateral surface is wide above, but then narrows into a thin edge at the bottom. The bottom of the sacrum is broad and expanded as it appears to be directed forward and upward. On the other hand, the apex is directed downwards as it presents an oval surface for its articulation with the coccyx (Saladin, 2003). Lastly, the vertebral canal goes throughout the entire part of the bone. It's from is triangular in shape, but the posterior wall is incomplete at the bottom from spinous processes and non-development of the laminae. As it lodges the sacral nerves, its walls are perforated by the posterior and the anterior sacral foramina through which the nerves do pass out.

It is also important to note that the sacrum articulates with about four bones. Above it is the lumbar vertebra while below it lays the coccyx, which is the tail bone. On either side of the sacrum lies the illium portion of the hip bone. The sacrum takes different shapes in males and females. It is shorter and wider in the female, and the lower part forms a greater angle with the upper form. While the upper part appears to be nearly straight, the lower half presents the largest amount of curvature. It is directed more obliquely backward, which increases the size of the cavity known as the pelvic cavity. In the males, the curvature appears to distribute evenly over the whole bone and also more massive than in the females.

Sometimes the sacrum could consist of six pieces, but occasionally reduced to four. There are also cases where the uppermost transverse tubercles fail to join with the rest of the ala, or the sacral anal may appear to be open. Notably, it varies considerably in respect to the degree of its curvature.

The coccyx, also known as the tailbone, is the last segment if the ape vertebral column. It comprises of about three to five fused or separate vertebrae below the sacrum. It is also attached to the sacrum the sacrococcygeal symphysis, a fibrocartilaginous joint that allows limited movement between the coccyx and the sacrum. The coccyx is the remnant of a vestigial tail in humans and other tailless primates. However, it is not entirely useless as it is an attachment for a number of tendons, muscles and ligaments. This makes it necessary for patients and physicians to pay attention to the attachments when considering surgically removing the coccyx. Moreover, it is part of the tripod structure that acts as support for a person who is sitting. If a person sits while facing forward, the inferior rami of the ischium and the ischial tuberosities take a large portion of the weight.  However, as the person leans backward, more weight goes to the coccyx.

The anterior side of the coccyx is important for the attachment of a collection of muscles that perform a number of various functions. This group of muscles known as the levator ani muscle includes iliococcygeus, coccygeus, and pubococygeus. The coccyx offers support to the anus through the anoccygeal raphe (Saladin, 2003). Usually, the coccyx is made up of four rudimentary vertebrae.

Scoliosis refers to a disorder that causes an abnormal curve of the backbone or the spine. While the spine has normal curves from the sides, it should appear straight from the front. Kyphosis refers to a curve seen from the side where the spine appears to be bent forward. On the other hand, Lordosis refers to the curve from the side in which the spine appears to be bent forward. Individuals with scoliosis develop curves on either side where the bones of the spine twist upon each other (DeWald, 2003).

This condition is very common among girls more than the boys. While it can be seen at any age, it is common in those over ten years of age. Moreover, it is hereditary in that individuals with scoliosis may have children with it. More often than not, the causes of scoliosis are unknown. However, some of the cases fall under two groups. The first is the functional group where it appears to be a temporary condition. The curvature comes about as a result of another cause, for example, a leg being shorter than the other from appendicitis or muscle spasms. The second group is known as the structural group, in which the spine appears to be abnormal. The curvature is as a result of another disease process such as muscular dystrophy, birth defect, connective tissue disorders, metabolic diseases, or Marfan's syndrome.  

There are various symptoms that are associated with the spine being curved. The opposite sides of the body may not be level. A person may feel back pain or tire easily when engaged in activities that require a lot of trunk movement. The head may also appear to be off center, and the shoulder or hip higher than the other. An individual with this condition may also walk with a rolling gait.

It is important to note that scoliosis usually appears around the age of ten years. Most school systems offer a number of screening programs that diagnose scoliosis. The most common of the tests is to have a child stand with his feet straight ahead, while the knees are locked. Then the child slowly bends over so as to touch the toes. If there is anything abnormal, it is important that a doctor be contacted for routine appointments for a month or two.

Notably, most children do not necessarily need treatment for scoliosis if the curvature appears to be mild. There are also physical exams that a child could take, which include undressing from the waist up. The child should then face forward while the feet are straight and palms inward. While keeping the knees locked, the child can then bend slowly over the toes while trying to touch the toes. The doctor then takes a look at the spine for the straight appearance. Notably, X-rays can also be taken to measure the curvature. The doctor can recommend treatment depending on the degree of the curvature or if the condition gets worse (DeWald, 2003).    

A majority of cases involving scoliosis do not require treatment. One example is if the curve stands less than twenty five degrees. The child can go back for re-examination after every four or six months. On the other hand, if the curve is less than twenty five degrees but less than thirty, the treatment can involve the use of a back race. For cases with curves of more than forty degrees, surgical correction can be an option. Surgery involves the fusion of vertebrae together so as to correct the curve (Hawes 2006). This process may include the insertion of rods next to the spine so as to reinforce the surgery. However, the most important thing to note about treatment is that it depends on how the curve can worsen. Scoliosis is not a preventable condition as the causes are not yet understood. However, if it is detected early enough, children can be treated so as to prevent further curvature.