CORTICOSPINAL TRACT-DEFICITS (UMN SIGNS)

SUMMARY

POSITIVE SIGNS (ABNORMAL BEHAVIORS)

1. Hypertonia & spasticity: initially flaccid paralysis & areflexia, hypertonia classically sets in after period of spinal shock (8-12 weeks)
2. Hyper-reflexia
3. Release of primitive reflexes: extensor plantar response, Hoffman's sign (UL sign)

4. Extrapyramidal signs: athetosis, dystonia
5. Extensor posturing (UL flexors > UL extensors & LL extensors > LL flexors)

NEGATIVE SIGNS (PERFORMANCE DEFICITS)
1. Pronator drift: first to occur, before weakness or reflex changes
2. Hemiplegia/hemiparesis, paraplegia/paraparesis (weakness of LL)
3. Loss of abdominal reflexes on the affected side

4. No muscle wasting

Reference(s)

R.M.H McMinn (1998). Last’s anatomy: regional and applied. Edinburgh: Churchill Livingstone. Get it on Amazon.
Drake, Richard L., et al. Gray's Anatomy for Students. Elsevier, 2023. Get it on Amazon.