Sexadactyly or hexadactyly is a genetic condition in which a person has six fingers on one or both hands, or six toes on one or both feet. This is a genetically inheritable condition; it is actually autosomal-dominant; and some populations feature a larger proportion of six-fingered people. Sexadactyly, or hexadactyly, is not merely defined as having six finger per hand or six toes per foot. It requires that each of the six fingers have its own ray, so that no two fingers would be more "merged" than on a normal hand on X-rays (as in most forms of polydactyly). Nonspecialists and the media however use the terms interchangeably.
Notable cases
It has been rumored that Anne Boleyn, wife of King Henry VIII of England and mother of Queen Elizabeth I of England, had six fingers on one hand. The biblical giant Goliath is said to have had six fingers on each hand and six toes on each foot: 2 Samuel 21:20 And there was yet a battle in Gath, where was a man of great stature, that had on every hand six fingers, and on every foot six toes, four and twenty in number; and he also was born to the giant. - KJV 1 Chronicles 20:6 And yet again there was war at Gath, where was a man of great stature, whose fingers and toes were four and twenty, six on each hand, and six on each foot and he also was the son of the giant. - KJV In fiction, Thomas Harris' character Hannibal Lecter has sexadactyly of the left hand, with mid-ray duplication. Count Tyrone Rugen of The Princess Bride also had six fingers on each hand, which made finding a good sword difficult for him.
