Upper Motor Neuron Lesion Upper motor neurons originate in the brain and brainstem, carrying motor signals through tracts like the corticospinal and corticobulbar tracts. Damage to these tracts above the pyramidal decussation causes contralateral weakness, while damage below causes ipsilateral weakness. Symptoms include spasticity, increased tone and reflexes, clonus, and an extensor plantar response. Weakness follows a pyramidal pattern with anti-gravity muscles stronger and flexors dominating over extensors, leading to issues like hemiplegia and circumductive gait.

1. Upper Motor
Neuron Lesion
BY:
NUR ADILIA
NUR ATIKAH
SITI HAJAR
FATHIRAH AINA

2. 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

4. 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

5. Upper Motor Neuron Weakness
• Increased tone ( spasticity)
– Spastic catch: mild spasticity during flexion
– “Clasp-knife “phenomenonrelaxation 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

6. • Pyramidal pattern
weakness
• *Anti Gravity Muscles
are stronger *
• Flexor in UL stronger
than extensor
• Extensor in LL
stronger than flexor
• Eg : -hemiplegia
-Circumductive gait

7. Babinski Reflex