Question

Which of the following symptoms would correspond to a left-sided upper motor neuron lesion to cranial nerve XI?

1) Weakness when turning the head to the left, especially against resistance
2) Some shoulder drop on the left side
3) Weakness when elevating the left arm and shoulder
4) Left-sided downward and lateral rotation of the scapula
5) Weakness when performing cervical lateral flexion to the left

Answer 1

A left-sided upper motor neuron lesion to cranial nerve XI would result in weakness when turning the head to the left, especially against resistance.

Step-by-step explanation:

A left-sided upper motor neuron lesion to cranial nerve XI would correspond to the symptom of weakness when turning the head to the left, especially against resistance. This is because the cranial nerve XI, also known as the accessory nerve, innervates the sternocleidomastoid and trapezius muscles, which are responsible for head and shoulder movements. A lesion in the upper motor neurons of the left side would affect the axons that control the cranial nerve XI on that side, leading to weakness in head turning to the left.