Upper motor neuron lesion
Classification and external resources
The motor tract.
DiseasesDB	27852

An upper motor neuron lesion is a lesion of the neural pathway above the anterior horn cell or motor nuclei of the cranial nerves. This is in contrast to a lower motor neuron lesion, which affects nerve fibers traveling from the anterior horn of the spinal cord to the relevant muscle(s).

Contents 1 Symptoms 2 Corticospinal/pyramidal tract 3 See also 4 References 5 External links

[edit] Symptoms

• Spasticity, increase in tone in the extensor muscles (lower limbs) or flexor muscles (upper limbs)
• Clasp-knife response where initial resistance to movement is followed by relaxation
• Weakness in the flexors (lower limbs) or extensors (upper limbs),^[1] but no muscle wasting
• Brisk tendon jerk reflexes
• Babinski sign is present, where the big toe is raised (extended) rather than curled downwards (flexed) upon appropriate stimulation of the sole of the foot. The presence of the Babinski sign is an abnormal response in adulthood.
• increase deep tendon reflex (DTR)
• Pronator drift ^[2]

[edit] Corticospinal/pyramidal tract

These are the neural tracts which descend in the spinal cord, in the lateral columns, carrying signals for voluntary movement of skeletal muscle. These nerve fibers usually originate in the cerebral cortex, then gather in the internal capsule before crossing over to the opposite side (decussation) in the medullary pyramids and proceeding down the spinal cord to meet lower motor neurones in the anterior horn.

[edit] See also

• Upper motor neuron
• Lower motor neuron lesion

[edit] References

1. ^ -261423104 at GPnotebook
2. ^ "The Precise Neurological Exam". http://edinfo.med.nyu.edu/courseware/neurosurgery/motor.html. Retrieved 2009-11-28. 

[edit] External links

• http://www.med.yale.edu/caim/cnerves/cn7/cn7_13.html
• http://www.lib.mcg.edu/edu/eshuphysio/program/section8/8ch3/s8ch3_34.htm

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v • d • e Cerebral palsy and other paralytic syndromes (G80-G83, 342-344) Paresis and plegia NOS Paralysis · Quadriplegia · Triplegia · Hemiplegia/Hemiparesis · Paraplegia/Diplegia · Monoplegia Flaccid vs. spastic Upper motor neuron lesion: Spastic diplegia · Spastic paraplegia (Hereditary spastic paraplegia) Lower motor neuron lesion: Flaccid paralysis Specific types Cerebral palsy · Cauda equina syndrome · Locked-in syndrome central nervous system navs: anat/physio/dev, noncongen/congen/neoplasia, symptoms+signs/eponymous, proc