Final answer:
Hemiplegia is paralysis affecting one side of the body, which can result from trauma to the spinal cord, such as in a hemisection, or from a stroke. Lesions on the lower motor neurons cause flaccid paralysis, while upper motor neuron damage leads to spastic paralysis. Stroke is a leading cause of disability and can result in permanent hemiplegia.
Step-by-step explanation:
The suffix '-plegia' indicates paralysis, so the term 'hemiplegia' refers to the paralysis of one side of the body. This can occur due to various reasons, including spinal cord injuries or strokes. For instance, spinal cord injuries can interfere with the communication between the brain and the body, potentially leading to paralysis. A hemisection of the spinal cord, usually caused by trauma, can result in hemiplegia where one limb or side of the body is paralyzed. The sensory deficits that may occur alongside such paralysis can be complex, depending on the damage to sensory nerve pathways.
Regarding motor control, lesions on the lower motor neuron (LMN) can lead to a type of paralysis termed 'flaccid paralysis', characterized by a reduction in muscle tone and loss of reflexes. On the other hand, upper motor neuron (UMN) lesions could result in spastic paralysis, where muscle tone is retained and increased, leading to spasticity.
In the context of a stroke, the brain's damaged area may lose its normal function, potentially leading to an inability to move or feel on one side of the body—a condition that may be described as hemiplegia. Strokes are the most common cause of disability, and their symptoms may be transient or permanent, heavily influenced by the severity of the stroke and the timeliness of treatment.