What characterizes spinal shock following an acute spinal cord injury?

Spinal shock is a temporary condition following an acute spinal cord injury characterized by the absence of all voluntary movement and often a loss of reflexes below the level of the injury. This condition occurs immediately after the injury and can result in flaccid paralysis and a complete loss of muscle tone, leading to hypotonia. The key feature is the loss of motor function due to disrupted neural pathways for movement, which manifests as an inability to initiate any voluntary movements.

In contrast, exaggerated reflex responses would typically be seen in conditions known as upper motor neuron lesions, while neurological recovery can sometimes vary and may not be consistently delayed as a characteristic of spinal shock. Spasms may occur later on, but they are more associated with reflex activity returning after the initial shock phase has resolved. Therefore, the absence of all voluntary movement during spinal shock is the defining characteristic of the state immediately following the injury.