Ataxia is a lack of co-ordination in the muscles. It is a symptom of damage to part of the central nervous system. Locomotor ataxia involves a lack of balance, or equilibrium. Patients must stand on a broad base, eyes open, or they will sway or even fall. The swaying increases if they shut their eyes. Ataxia has many causes, locomotor ataxia may be due to syphilis for example. Many diseases that damage the central nervous system may cause ataxia, including tumours of the cerebrum or cerebellum, some deficiency diseases, and diseases of the spinal cord. Ataxia may also result from overuse of such drugs as barbiturates or alcohol. Research Ataxia
The autonomic nervous system is responsible for the self-controlling aspects of the body's nervous network, and is under the control of the cerebral cortex, the hypothalmus, and the medulla oblongata. Working in tandem with the central nervous system, the autonomic nervous system features two subsystems which regulate body functions such as involuntary smooth muscle movement and heart rate. These two subsystems are called the sympathetic and parasympathetic nervous system, and their functions operate in opposition to one another, delicately balancing the bodily functions which they control. The sympathetic nervous causes fight or flight responses in moments of stress or stimulus, such as increased heart rate, saliva flow, and perspiration. The parasympathetic system counterbalances these effects by slowing the heart rate, dilating blood vessels, and relaxing involuntary smooth muscle fibres. Viewed individually, the sympathetic nervous system, also referred to as the thoracolumbar system, features a series of nerves which branch out of the spinal cord between the first thoracic vertebra and the second lumbar vertebra. These nerve fibres join into a long trunk of fibres, called the sympathetic trunk, on each side of the spinal cord. Along the sympathetic trunk are enlarged clusters of nerve fibres, called ganglia.
From these ganglia, a number of nerve fibres extend throughout the body's tissues. Many of these nerves create additional ganglia, such as the celiac ganglia and the mesenteric ganglia. The sympathetic nerves are responsible for contracting involuntary smooth muscle fibres, viscera, and blood vessels, speeding up the heart rate, and dilating the bronchial tubes in moments of stress. The parasympathetic nervous system, also referred to as the craniosacral system, features ganglia in the midbrain, in the medulla oblongata, and in the sacral region. The first two, the cranial ganglia of the parasympathetic system, give pass impulses to the facial, oculomotor, glossopharyngeal, and vagus nerves. The sacral group of parasympathetic nerves originate at the second, third, and fourth vertebrae and extend nerves to the bladder, the distalcolon, the rectum, and the genitals. The nerves of the parasympathetic nervous system are responsible for conserving and restoring energy in the body following a sympathetic response to stress. Research Autonomic Nervous System
The basilar part of the occipital bone is that part which forms the floor of the cranial cavity, housing the brain. The basilar part meets the vomer and sphenoid bone in the anterior, and the temporal bones at the sides. The most apparent characteristic of the basilar part of the occipital bone is the large foramen magnum, a round opening in the bone which allows the spinal cord to pass through the skull. Research Basilar Part
The development of bed sores in a patient in hospital, is usually considered to indicate bad nursing. Bed sores occur from interruption of the nutrition of areas of skin where the blood supply has been impaired by pressure. Bed sores are almost inevitable in some patients. The very thin, the very heavy, the incantinent and those who through some injury to the spine have lost the sensation of the skin at these points are most likely to develop pressure sores. Common sites for bed sores are the sacral area and the heels. In patients with septic conditions, nutrition is impaired by prolonged fever and there is frequently anaemia. Their toxic condition renders them less likely to move about and the greatest care needs to be taken to prevent the development of these pressure ulcers. Frequent change of position and massage of pressure points with spirit followed by powder is the best method of prevention. Early post-operative mobilisation of all patients who are fit to get up has done much to prevent this distressing complaint.
In unconscious patients or those who have had some injury to the spinal cord, a large pressure sore can develop as soon as twelve hours after the injury or onset of the illness. A bed sore on the sacral area may even develop from the patient's position on the operating table during a long operation. Although pressure sores rarely develop over the scapulae or the elbows, these points are subject to soreness and require similar preventive treatment when a patient is washed. An ulcer may develop on the shin from the weight of the other leg, if the legs of an unconscious patient are left crossed. Research Bed Sores
The brain is the primary component of the nervous system, occupying the cranial cavity. Without its outermost protective membrane, the dura mater, the brain weighs an average of 1.4 kilograms, comprising about 97% of the entirecentral nervous system. The brain is connected to the upper end of the spinal cord (which connects through the foramen magnum of the skull) and is responsible for issuing nerve impulses, processing nerve impulse data, and engaging in the higher order thought processes. The brain is divided into three parts: the large cerebrum, the smaller cerebellum, and the brainstem leading to the spinal cord. The brainstem is also descriptively divided into the medulla oblongata, the midbrain, and the pons. The right hemisphere of the brain is a part of the cerebrum. The cerebrum, or forebrain, forms the bulk of the brain, formed of a large mass of white and grey neural fiber in the upper cranium. It is responsible for the higher thought processes (memory, judgement, reason), processing sensory data, and with initiating willful motor processes, such as voluntary muscle flexion. The cerebrum is composed of two lateral halves, or hemispheres, which feature a number of folds (gyri) and furrows (sulci) and which are connected in the middle at the medulla. Containing about a trillion neurons, the human brain is the most complex mechanism known, and its many functions are still largely a mystery. Research Brain
The brain stem operates automatically to control vital body functions such as breathing and blood pressure. It is a eight centimeter long stalk of nerve cells and fibres that joins the upper part of the spinal cord with the brain. The medulla oblongata is the lowest part of the brain stem and serves as the site of connection between the brain and the spinal cord. The pons is located in the brainstem, vertically between the midbrain and the medulla oblongata, and sagittally between the cerebellum and the pituitary gland. It is responsible for serving as a bridge between the cerebrum, the cerebellum, and the medulla oblongata. The brain stem is an extension of the spinal cord and acts as a highway for messages traveling from other parts of the brain to the spinal cord. The spinal cord and the brain form the central nervous system (CNS), which controls all of the body's basic functions such as breathing, the rate of your heart beat, and body temperature. Research Brain Stem
The cerebellum is a division of the brain, located below the cerebrum and in the posterior of the brain. The cerebellum features a central portion, called the vermis, and two side portions, or hemispheres - one on each side. It is the responsibility of the cerebellum to coordinate and modify the resultant activity of impulses and orders sent from the cerebrum. It does this by receiving information from nerve endings all over the body, such as the balance and equilibrium centers in the inner ear, and adjusts and fine tunes these actions by passing the regulating signals to the motor neurons of the brain and spinal cord. Damage to the cerebellum therefore results in loss of ability to maintain precise muscular coordination and fine cooperative actions of the motor processes (called ataxia). Research Cerebellum
The cervical vertebrae are the first (upper) seven in the vertebral column. The first cervical vertebra is the atlas, so called because it directly bears the weight of the skull. The second cervical vertebra is called the axis, because it admits the rotation of the skull by allowing the atlas to pivot upon it. The other five cervical vertebrae have no names, but are called by their number (i.e., third cervical vertebra). Each of the cervical vertebra features a body and an arch. The body of each vertebra in the column bears the weight of the vertebrae above it (and the skull), while the arch serves to create a canal-like area along the spine to house and protect the spinal cord. Every cervical vertebra has a foramen in each of its transverse processes. The arch of the vertebra features a small knob or prominence, called an anterior tubercle. The anterior tubercles on the sixth cervical vertebra are particularly large and are known as the carotid tubercles. Research Cervical Vertebrae
Colostomy is the operation of opening into the colon, or lower portion of the intestine. This procedure is one of the most important in abdominal surgery. It is sometimes necessary as a life- saving measure. It may be temporary or permanent as an artificial anus in the radical treatment of rectal cancer. Because of its appearance, its inconvenience and the very thought of an artificial opening in the abdominal wall a great deal of care is necessary to allay the anxieties of patients and their relatives when colostomy is necessary.
In some cases of acute intestinal obstruction the surgeon explores the abdomen and finds perhaps a large mass in the region of the pelvic colon or rectum that cannot be removed. An emergency colostomy is then performed in the transverse colon with the immediate purpose of saving life and with the further objective of providing temporary drainage should the growth be removable at a later date. In some such cases, when at first sight the primary cause of the obstruction seems beyond any possibility of surgical removal, after several weeks of colostomy drainage the infection subsides and the affected portion of bowel may then be removed. Colostomy may be necessary as a preliminary to other operations involving removal of the large bowel. Such an occasion arises if diverticulitis has produced vesico-colic fistula (between the colon and bladder). In some cases of severe incontinence due to abnormality or injury to the anus, a left iliac colostomy enables the patient to be free of the terrible inconvenience of perpetual soiling in the perineum. Injuries or abnormalities of the spinal cord produce paralysis of the anal sphincter mechanism and sometimes colostomy is essential. Congenital absence of the rectum or anus requires an emergency colostomy within a day or so of birth.
There are two main forms of colostomy. First is the loop colostomy which has two limbs. The opening is at the apex of the loop and the bowel has not been divided completely across. A variation of the loop colostomy is the double- barrel form in which the two limbs of the loop are separated by a piece of skinrafter complete division. This is also described as a defunctioning colostomy as it prevents the spill of faeces from the proximal to the distalloop. A second variety is the spur colostomy where a spur is formed by suturing the two ends together for several centimeters inside the abdomen. This is of particular value if the colostomy is temporary as the spur can be destroyed by a crushing clamp without risk of peritonitis or perforation since the limbs have become sealed together. When the spur breaks down, the artificial opening on the surface shrinks and sinks back below the skin level. The aim is that this should close spontaneously without further operation. The third type is the terminal colostomy in which the distal portion of bowel is removed completely or in the case of excision of rectum the lower end is closed to form a blind end. In grave emergencies the simplest form of colostomy is performed in which a loop of colon is brought out through the abdominal wall, where it is held by the insertion of a glassrod passed through a small hole in the mesentery. The ends of the glassrod are connected by a loop of rubber tubing which forms a 'bucket handle' . The abdominal wall is closed around the protrusion of the colostomy. Exteriorisation is another way of performing a colostomy. If a growth is present in a part of the bowel which can be brought readily through the abdominal wall (e.g. transverse or pelvic colon) the affected loop containing the growth is left outside and the peritoneum, muscles and skin are closed around the base of the loop where the two limbs converge. The loop of colon containing the growth is then removed, leaving two open ends of el which can later be joined by crushing the spur between them. This operation avoids the handling of growth or unprepared bowel while the peritoneal cavity is open and so diminishes the risk of peritonitis. A formal operation for closure is required if a spur has not been made.
At the end of the operation a small incision is usually made in the apex of the loop to allow the immediate discharge of gas and faecal material which is collected as cleanly as possible before the patient leaves the theatre. A dressing of petroleum jelly gauze or tullegras is applied on the exposed bowel. The skin incision may be sealed with Whitehead's varnish and a pad of cellulosetissue and wool is bandaged lightly over the opening. For fear of contaminating the abdominal wound before the peritoneal cavity has become sealed, the former practice was to leave the colostomy unopened for 48 hours. The initial opening may be enlarged by the surgeon two or three days after the colostomy has been raised. The bowel is usually divided (without anaesthetic) by an electric cautery which seals the blood vessels and prevents bleeding from the very vascular mucousmembrane and muscle wall of the bowel. A method of draining the colostomy is by the use of Paul's tube. This is an angled wide glass tube which is inserted through a hole in the colostomy loop. It is tied in position in the same way as the caecostomy catheter and connected to a bedside jar with wide, thin, latex tubing. Research Colostomy
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Ataxia
