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The Spinal System. The Spinal Cord. A rises from the base of the medulla oblongata. Is a cylinder of nervous tissue enclosed in the spinal canal of the vertebral column. The spinal cord is unique to the nervous system of vertebrates.
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The Spinal Cord • Arises from the base of the medulla oblongata. • Is a cylinder of nervous tissue enclosed in the spinal canal of the vertebral column. • The spinal cord is unique to the nervous system of vertebrates. • In an adult human it is about 45 cm (18 in) long and roughly as thick as a finger. • Spinal nerves from the spinal cord branch off to various parts of the body
The Spinal Cord • It is covered on the outer surface by meninges (Pia Mater, Arachnoid, Dura Mater) • In the center is a hollow core called the central canal which contains CSP • Does not run the full length of the vertebral column. It narrows down to several loose strands of nerve tracts that exit the sacral and coccogeal vertebrae.
Ascending tracts: • Found along dorsal portion of spinal cord • Carry information up the spinal cord to the brain • Descending tracts: • Found along the ventral and lateral portions of the spinal cord • Carry information down from the brain to various effectors.
Divisions of the spinal cord The are five divisions of the spinal cord, corresponding to the different groups of vertebrae: •Cervical: 7 vertebrae (C1–C7) •Thoracic: 12 vertebrae (T1–T12) •Lumbar: 5 vertebrae (L1–L5) •Sacral: 5 (fused) vertebrae (S1–S5) •Coccygeal: 3–5 (fused) vertebrae (Tailbone) Note that although there are seven cervical vertebrae (C1-C7), there are eight cervical nerves (C1-C8). In the diagram to the right, the cervical nerves are the ones labeled and the vertebra are shown in between.
Disorders Damage through accident or injury to the spinal cord, called myelopathy, can result in paraplegia or quadriplegia, depending on the level within the spinal cord of the damage. These conditions may be permanent since nerve fibers in the spinal cord usually do not regenerate.
SPINAL CORD INJURY • An injury to the spinal cord usually begins with a sudden, traumatic blow to the spine that fractures or dislocates vertebrae. • The damage begins at the moment of injury when displaced bone fragments, disk material, or ligaments bruise or tear into spinal cord tissue. • Most injuries to the spinal cord don't completely sever it. Instead, an injury is more likely to cause fractures and compression of the vertebrae, which then crush and destroy the axons, extensions of nerve cells that carry signals up and down the spinal cord between the brain and the rest of the body. • An injury to the spinal cord can damage a few, many, or almost all of these axons. Some injuries will allow almost complete recovery. • Others will result in complete paralysis.
Spinal Shock Immediately following a spinal cord injury, spinal shock occurs. Spinal shock is a period of time when all reflexes, movement, and feeling are absent below the level of injury. Spinal shock may take hours, days, weeks, or months to resolve. The return of reflex activity below the level of injury is a sign that the person is coming out of spinal shock. The reason for spinal shock is not known. Treatment: IV Steroids (methylprednisolone)
Spinal Cord Injuries The level at which the injury occurs determines what part of the body will be effected.
A complete spinal cord injury means there is a total blockage of signals at the point of injury. There will not be any feeling or movement below the level of injury. A complete spinal cord injury can change the control of all the functions of the nervous system.
An incomplete spinal cord injury means that there is partial damage to the spinal cord. Some feeling or movement remains below the level of injury. The amount of feeling and movement lost will depend on how much damage is done to the spinal cord.
The most common causes of spinal cord injuries in the United States are: •Motor vehicle accidents. Auto and motorcycle accidents are the leading cause of spinal cord injuries, accounting for more than 35 percent of new spinal cord injuries each year. •Falls. Spinal cord injury after age 65 is most often caused by a fall. Overall, falls cause more than one-quarter of spinal cord injuries. •Acts of violence. Around 15 percent of spinal cord injuries result from violent encounters, often involving gunshot and knife wounds, according to the National Spinal Cord Injury Statistical Center. •Sports and recreation injuries. Athletic activities, such as impact sports and diving in shallow water, cause about 9 percent of spinal cord injuries. •Alcohol. Alcohol use is a factor in about 1 out of every 4 spinal cord injuries. •Diseases. Cancer, arthritis, osteoporosis and inflammation of the spinal cord also can cause spinal cord injuries
Video https://www.youtube.com/watch?v=M5rlKmzA_p0&index=1&list=PLOW85HV_qUD48R5Ohy0W5azw7K-9-42XF http://www.shepherd.org/resources/emergencycards
CASE STUDY http://wps.prenhall.com/chet_lemone_medicalsurg_4/61/15850/4057684.cw/content/index.html http://www.mhhe.com/biosci/ap/ap_casestudies/cases/ap_case09.html