Question

A horse is showing signs of motor problems seemingly localized to the right leg. After an exam, the veterinarian notes that the right hind limb muscles do not exhibit any atrophy or decreased tone. In fact, muscle tone appears moderately increased and reflexes are hyperactive. All other limbs are normal. What would be the best explanation for these results?

a. A stroke resulting in damage to the right precentral gyrus.

b. An accidental injury localized to her right lateral spinal cord at T10.

c. Age related death of lumbar lower motor neurons.

d. An autoimmune condition that selectively demyelinates the right sciatic nerve

Answer 1

b. An accidental injury localized to her right lateral spinal cord at T10

Explanation: There is no any atrophy or decreased tone.Muscle tone appears moderately increased and reflexes are hyperactive. All these are the features of Upper motor neuron lesion.

As there in involvement of only one limb. hence lesion must be present within the spinal cord at the segment supplying the right leg.

right lateral spinal cord at T10 supplies the muscles of the limb. Hence injury to this level of the spinal cord may cause the motor problems in the right leg.