He touched the roll-edged brim of his sombrero, and Drew noted that his arm was crooked as if in the past it had been broken and poorly set.
Drew noted the man had no arms past the shoulder socket. 
mnli hypothesis: Drew noted the man had no arms past the shoulder socket.  premise: He touched the roll-edged brim of his sombrero, and Drew noted that his arm was crooked as if in the past it had been broken and poorly set.