Mr Smith Staggered Home After a Long Night at the Local

Essay

Mr. Smith staggered home after a long night at the local pub. While attempting to navigate the stairs, he passed out cold and lay all night with his right armpit straddling the staircase banister. When he awoke the next morning, he had a severe headache, but what bothered him more was that he had no sensation in his right arm and hand. Explain what caused this symptom in his arm.