This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
A person with intractable pain over the right leg is benefited by 
Select and explain. 
A. Right spinothalamic tract cordotomy, B. Left Spinothalamic tract cordotomy, C. Right hemicordotomy, D. Left hemicordotomy
B: Left Spinothalamic tract cordotomy
Answer: B: Left Spinothalamic tract cordotomy 
Explanation: (B) Left Spinothalamic tract cordotomy > Spinothalamic tract Touch sensation is transmitted by ventral spinothalamic tract Pain and temperature pain are transmitted by lateral spinothalamic tract> Fibers of spinothalamic tract cross in the anterior commissure of the cord to the opposite> Hence intractable pain over the right leg is benefited by left spinothalamic tract cordotomy.> In anterolateral cordotomy, the spinothalamic tracts are carefully cut to relieve severe pain.