<P> Neurapraxia results in temporary damage to the myelin sheath but leaves the nerve intact and is an impermanent condition; thus, Wallerian degeneration does not occur in neurapraxia . In order for the condition to be considered neurapraxia, according to the Seddon classification system of peripheral nerve injury, there must be a complete and relatively rapid recovery of motor and sensory function once nerve conduction has been restored; otherwise, the injury would be classified as axonotmesis or neurotmesis . Thus, neurapraxia is the mildest classification of peripheral nerve injury . </P> <P> Neurapraxia is very common in professional athletes, especially American football players, and is a condition that can and should be treated by a physician . </P> <P> A variety of nerve types can be subjected to neurapraxia and therefore symptoms of the injury range in degree and intensity . Common symptoms of neurapraxia are disturbances in sensation, weakness of muscle, vasomotor and sudomotor paralysis in the region of the affected nerve or nerves, and abnormal sensitivity of the nerve at the point of injury . It has been observed that subjective sensory symptoms include numbness, tingling, and burning sensations at the site of the injury . Objective sensory symptoms are generally minimal in regards to touch, pain, heat, and cold . In cases of motor neuron neurapraxia, symptoms consist of flaccid paralysis of the muscles innervated by the injured nerve or nerves . Symptoms are often transient and only last for a short period of time immediately following the injury . However, in severe cases of neurapraxia, symptoms can persist for weeks or months at a time . </P> <P> The cause of neurapraxia is a neural lesion which causes a temporary block of nerve conduction without transection of the axon . A conduction block is classified as a 40% reduction in action potential amplitude over a short distance on the nerve, or a 50% reduction for a longer distance on the nerve . In neurapraxia, stimulation to the injured nerve results in a greater reduction in the action potential amplitude on the proximal site of the injury as opposed to the distal site . </P>

A temporary injury to the spinal cord that may resolve over time is called