Upper Motor Neuron Lesion

BY:NUR ADILIANUR ATIKAHSITI HAJAR

FATHIRAH AINA

Neuroanatomy UMN• motor neurons originate in the motor

region of the cerebral cortex or the brain stem and carry motor info to the final common pathway.

• Betz cell large pyramidal cells• UMN lesions result from damage of – Corticospinal tract– Cortico bulbar tract

Pyramidal Tract Lesion

Upper Motor Neuron Weakness

• If lesion is above pyramidal decussation ( level of lower medulla) weakness at contralateral to site of lesion

• If lesion occurs lower than the level weakness at ipsilateral to lesion

Upper Motor Neuron Weakness

• Increased tone ( spasticity)– Spastic catch: mild spasticity during flexion– “Clasp-knife “phenomenonrelaxation following

resistance to passive flexion of elbow or knee– Clonus rythmic involuntary muscle contractions

abruptly applied n sustained strtch stimulus • Brisk tendon reflex – KPR, biceps reflex,

triceps reflex• Extensor Plantar Response positive Babinski

• Pyramidal pattern weakness

• *Anti Gravity Muscles are stronger *

• Flexor in UL stronger than extensor

• Extensor in LL stronger than flexor

• Eg : -hemiplegia -Circumductive gait

Babinski Reflex