Upper motor neuron lesion

Answer 1

Upper motor neurons: they are the motor cells of cerebral cortex and subcortical centres whose axons constitue the pyramidal and extra-pyramidal tracts(which then descend to end around the motor nuclei of cranial nerves in brainstem and anterior horn cells of the spinal cord)

Lower motor neurons: they are the cells of motor nuclei of cranial nerves and anterior horn cells of spinal cords, and their axons which constitute the motor fibres of the peripheral nerves that terminate in the motor end plate of striated muscles.

Answer 2

Ibraheem abdullah al jaza PBL .. Group 1 .. CNS C . n . 0610211 Day 2 .. " upper motor neuron lesion " ______________________________________________________________________________ Upper motor neuron lesion 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 Injury to cerebral descending (corticonuclear) fibres above the brainstem or spinal motor nerve nucleus. Upper motor neuron lesions are indicated by spasticity, muscle weakness, exaggerated reflexes, and an out toeing (flaring) of toes and extensor plantar response 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) 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 medulla oblongata and proceeding down the spinal cord to meet lower motor neurones in the anterior horn.