Final answer:
The muscles of a patient with a spinal cord injury can be flaccid initially due to shock but can become spastic later on if upper motor neurons are involved. Lower motor neuron lesions, however, would lead to flaccid paralysis.
Step-by-step explanation:
The patient with a spinal cord injury will experience different types of muscle paralysis depending on the location and nature of the injury. Generally, in the acute phase immediately after injury, muscles may be flaccid due to shock. However, as the injury progresses, spasticity can develop, especially with injuries involving the upper motor neurons (UMN). With UMN lesions, muscle tone is retained, leading to spastic paralysis.
Conversely, a lesion on the lower motor neurons (LMN) would result in flaccid paralysis, characterized by a complete or partial loss of muscle tone as well as weakness or absence of muscle contractions and reflexes. Therefore, depending on the specific neuroanatomy affected by the spinal cord injury, paralysis can present as either flaccid or spastic, or sometimes both can be present if different components of the nervous system are affected at different times.