Upper motor neuron syndrome

Typically manifested by a positive Babinski’s sign.

Upper motor neuron damage to axons in the spinal cord results in a characteristic pattern of ipsilateral deficits.

Upper motor neuron injury findings include hyperreflexia, hypertonia and muscle weakness.

Upper motor neuron signs—weakness, spasticity, clumsiness, altered tonus, hyperreflexia and pathological reflexes, including Hoffmann’s sign and inverted plantar reflex a positive Babinski sign.

Axons form the corticospinal tract, with the Betz cells are referred to as upper motor neurons (UMN).

The upper motor neuron syndrome are the motor control changes in skeletal muscle after an upper motor neuron lesion.

Upper motor neuron lesions affected muscles potentially have features of altered performance including:


decreased motor control including decreased speed, accuracy and dexterity

altered muscle tone with a decrease or increase in the baseline level of muscle activity

decreased endurance

exaggerated deep tendon reflexes including spasticity, and clonus.

A diagnosis of spasticity is often used interchangeably with upper motor neuron syndrome, but it is an exaggerated stretch reflex, which means that a muscle has a reflex contraction when stretched, and that this contraction is stronger when the stretch is applied more quickly.

Spasticity is one component of the upper motor neuron syndrome, but it is of much less clinical significance than other features such as decreased strength, decreased control and decreased endurance

It is seen in conditions where motor areas in the brain and/or spinal cord are damaged or fail to develop normally: spinal cord injury, cerebral palsy, multiple sclerosis and acquired brain injury including stroke.

Impairment of muscle function results in problems with movement, and posture.

Assessment of motor control may involve physicians, physical therapists, rehabilitation physicians, orthotists, occupational therapists, and speech-language pathologists: to include analysis of posture, active muscle movement, muscle strength, control and coordination, endurance, muscle tone and spasticity.

Muscles manifest a loss of selective movement, decreased ability to actively lengthen, limiting motor control.

Multiple muscles in a limb are usually affected in the Upper Motor Neuron Syndrome.

In the Upper Motor Neuron Syndrome there is usually an imbalance of muscle activity, such that there is a stronger pull on one side of a joint.

Exercise to improve proximal stability may be indicated, and is the mainstay of management, likely to need to be prescribed by a physical therapist or other health professional skilled in neurological rehabilitation.

Medical interventions include: baclofen, diazepam, dantrolene, or clonazepam.

Phenol injections or botulinum toxin injections into the muscle belly can be used to attempt to dampen the signals between nerve and muscle.


Leave a Reply

Your email address will not be published. Required fields are marked *