A 70-year-old man complains of weakness in his right leg. Physical examination is notable for hyperactive muscle stretch reflexes, a positive Babinski sign, and diffuse areas of weakness in his right leg. Although he can accurately distinguish sharp and dull pain in the right leg he is unable to distinguish these types of pain in his left leg. The most likely cause of these findings is a lesion in the:

Question

Quizplus · Accepted Answer

The symptoms suggest a lesion in the left lateral funiculus, which affects the corticospinal tract (causing weakness and hyperreflexia in the right leg) and the spinothalamic tract (causing loss of pain sensation in the left leg).

A 70-Year-Old Man Complains of Weakness in His Right Leg