QS Study

Difference between Upper and Lower Motor Neuron Lesion

Upper motor neuron

Pyramidal cell and its axon are called upper motor neuron. It occurs in the brain or the spinal cord as the consequence of stroke, multiple sclerosis, traumatic brain injury, and cerebral palsy. It Indicates that the lesion is above the anterior horn cell (i.e. spinal cord, brain stem, motor cortex). Medicines and therapy can help control symptoms like muscle spasms and help you walk and talk more easily. Structures involved: Central nervous system- cortex, brainstem, corticospinal tracts, spinal cord.

Lower motor neuron

Anterior horn cell of the spinal cord and its axon and cranial nerve nuclei and its axon are called lower motor neuron. It indicates that the lesion is either in the anterior horn cell or distal to the anterior horn cell (i.e. anterior horn cell, root, plexus, peripheral nerve). Structures involved: Cranial nerve nuclei/nerves and Spinal cord: anterior horn cell, spinal roots, peripheral nerve. Symptoms are; Muscle paresis or paralysis, Fibrillations, Fasciculations, Hypotonia or atonia Hyporeflexia etc.

Upper motor neurons convey the nerve impulses from upper to lower motor neurons and control the activities of muscles by signaling lower motor neurons. Lower motor neurons actually signal the muscle to contract. Both of these neurons when injured present with their own set of medical signs.

Different between upper and lower motor neuron lesion –