Complex sentence: Henry's naked and decapitated body could only be identified by his wife, thanks to a unique anatomical defect: on his left foot, he had six toes (polydactyly), which was confirmed when his tomb was opened in 1832.
Split into simpler sentences: Henry's naked and decapitated body could only be identified by his wife, because of his polydactyly. He had six toes on his left foot, which was confirmed when his tomb was opened in 1832.