Key features of upper and lower
motor neurone lesions
Upper motor neurone
Muscle tone Increased
Clonus Present
Muscle fasciculation Absent
Tendon reflexes Increased
Plantar response Extensor (Babinski’s sign)
Distribution Extensor weakness in upper limb and flexor weakness in
lower limb Whole limb(s) involved
Origin: cerebral cortex
Terminates: cranial nerve nuclei or spinal cord anterior horn
Lower motor neurone
Muscle tone Decreased
Clonus Absent
Muscle fasciculation Present
Tendon reflexes Depressed or absent
Plantar response Flexor (normal)
Distribution Weakness of muscle groups innervated by affected spinal
segment/root, plexus or peripheral nerve
motor neurone lesions
Upper motor neurone
Muscle tone Increased
Clonus Present
Muscle fasciculation Absent
Tendon reflexes Increased
Plantar response Extensor (Babinski’s sign)
Distribution Extensor weakness in upper limb and flexor weakness in
lower limb Whole limb(s) involved
Origin: cerebral cortex
Terminates: cranial nerve nuclei or spinal cord anterior horn
Lower motor neurone
Muscle tone Decreased
Clonus Absent
Muscle fasciculation Present
Tendon reflexes Depressed or absent
Plantar response Flexor (normal)
Distribution Weakness of muscle groups innervated by affected spinal
segment/root, plexus or peripheral nerve
