Hitchhiker's thumb: The myth. Some people have "hitchhiker's thumbs," which bend backwards with a large angle between the two segments (phalanges). The myth is that there are just two kinds of thumbs, straight thumbs (S) and hitchhiker's thumbs (H), and the trait is controlled by a single gene with two alleles, with the allele for S being dominant.
Jul 18, 2017 · Hitchhiker's thumb is otherwise known as distal hyperextensibility of the thumb. This is because of the genetic traits that make a person bend his 4.5/5(23).
Jun 18, 2019 · Hitchhiker’s thumb is a thumb that’s hypermobile, or very flexible, and able to bend backward beyond the normal range of motion. Known formally Author: Corey Whelan.