Human Anatomy & Physiology (9th Edition)

Published by Pearson
ISBN 10: 0321743261
ISBN 13: 978-0-32174-326-8

Chapter 12 - The Central Nervous System - Review Questions - Page 481: 36


Paraplegia, quadriplegia and hemiplegia are forms of paralysis that have some similar symptoms . However while paraplegia and quadriplegia are due to spinal cord injury, hemiplegia is due to damage of brain neurons. Paraplegia and quadriplegia are both due to transverse cutting ( transection) of the spinal cord at some level: A. Paraplegia is due to the transection of the spinal cord between the levels of vertebra T1 and L1. The result of a cut at this level is that both lower limbs experience paralysis but the upper limbs are not affected B. If the cut is made in the cervical region of the spinal cord -- between levels C1 and C7 of the vertebrae, both sets of limbs would become paralysed. This is called quadriplegia or tetraplegia. C. Hemiplegia is, so to speak, "a different kettle of fish." It is caused not by spinal cord transection but by injury to brain neurons. The common causes are strokes and tumors. The manifestations are usually contralateral to to the side of the cerebrum in which the injury occurred.

Work Step by Step

Paraplegia and quadriplegia are due to transections of the spinal cord with resultant paralysis or loss of functions caudal to the level of the cut Paraplegia results from cuts made between T1 and L1 vertebrae. In this case the lower limbs, but not the upper limbs, are affected The effect is loss of sensory and motor function--usually permanently. Quadriplegia. Quadriplegia or tetraplegia results if the spinal cord is transected in the cervical region--between C1 and C7. In such a case, all four limbs become paralyzed. Hemiplegia. Hemiplegia is a one-sided paralysis caused not by spinal cord injury, but by damage to motor neurons of the cerebral cortex. It is one-sided because the fiber tracts of the motor neurons of the cortex decussate ( cross to the other side) in the medulla, The result is that injury to right hemisphere motor neurons cause left-sided paralysis. In other words, the paralysis is contralateral to the site of brain injury. Some causes of hemiplegia are stroke (ischemia, blood clots), and tumors. The immediate symptoms of spinal cord transections may include the following: a. Hyporeflexia posterior( acudad) to the lesion b. Cessation of bladder and/or bowel reflexes c. Paralysis of muscles d. Increased sensitivity of muscles e.Decreased blood pressure. Some of these symptoms may not be permanent.
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