Case 5: Question 3

A 35-year-old woman complained that she had no feeling in her hands. She had burned her right hand on a hot pan but had not felt it. She said the feeling of numbness in her hands had a gradual onset, starting about 6 months previously. Examination indicated the following:

• normal strength and reflexes
• normal proprioception and vibration sense
• no response to pinprick and no temperature sensation in the thumb, index finger and third finger of both hands

Question 3: Where is the lesion?