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What is Hitchhiker's Thumb?

Hitchhiker's thumb is a recessive genetic trait.
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  • Written By: Mary McMahon
  • Edited By: Bronwyn Harris
  • Last Modified Date: 04 September 2014
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Someone who has a thumb which bends backward when extended is said to have a hitchhiker's thumb. This is a genetic trait, and it does not interfere with the thumb's normal functions. Hitchhiker's thumb is also not linked with any other genetic conditions; it is simply an interesting phenotype, akin to people who can curl their tongues. To see if you have a hitchhiker's thumb, make a fist and extend your thumb. If you notice a significant bend, you have inherited this trait.

Hitchhiker's thumb is a recessive trait, which means that people must inherit the gene from both parents for it to manifest. People can also carry the gene without exhibiting the trait, by inheriting the gene from one parent only. Recessive traits are particularly interesting because they can appear to flit in and out of a family with no apparent reason, thanks to the fact that they can lurk in generations of genes before manifesting.

Some people with a hitchhiker's thumb are capable of bending the joint in the thumb to extremes which may look uncomfortable to people who lack this genetic trait. You may also hear hitchhiker's thumb referred to as “hyperextension of the thumb” in a reference to this. There is no particular advantage or disadvantage of having a hitchhiker's thumb, and it certainly does not predispose people to hitchhiking.

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Having a hitchhiker's thumb is not the same thing as being double-jointed. People who are double-jointed display a trait known as hypermobility, which allows them to move their joints much further than is normal. In this case, all of the fingers of the hand can be bent and twisted in interesting ways, in addition to the thumb.

The study of recessive genetic traits can be very interesting, because it can reveal intriguing information about family and regional histories. Some teachers like to use the hitchhiker's thumb in classroom exercises which demonstrate the basic principles of genetic inheritance, showing students what a hitchhiker's thumb looks like and then encouraging them to collect data from classmates. In some families, such traits may become topics of discussion and commentary, with children being told that they have “inherited Aunt So-and-so's thumb” to give them a deeper connection with the rest of the family.

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anon968544
Post 16

There are advantages and disadvantages, Picking a guitar is a lot more challenging, in my opinion. My thumb starts to get sore after a while because when I hold my pick, my thumb naturally bends all the way back. I can't hold the pick normally.

anon357360
Post 15

It's been my observation that hitchhiker's thumbs is not only genetic but is frequent among Latina, Indian and Vietnamese women. Note Jessica Alba, Jennifer Lopez, Freda Pinto and Dr. Sapna Parikh. And men find this trait attractive in women!

I noted an article in a science and medical magazine that some women are pursuing the surgery to achieve this feature to please and attract men.

anon357347
Post 13

I have hitchhiker's thumb. There are advantages and disadvantages. Advantages: Unbeatable at thumb wrestling, can give great back massages. Disadvantages: Makes it harder to snap.

anon354265
Post 12

Both my thumbs bend back and I can also bend the MCP joint on my left hand forward but not on my right. I can also often fit my entire hand through small spaces that friends with thinner hands can't!

anon279529
Post 11

I remember doing an article in high school about what people will look like in the future, and found out humans are getting taller and more people are becoming double jointed with longer fingers. When I visited doctor for a broken and fractured finger, he saw my double jointed fingers and referred to them as deformities.

My mom quickly defended me telling him those are advances in human evolution and are blessings from our Lord. I have always been stronger than my peers in hand strength and feel truly blessed with my double jointed fingers. I have a history of jammed and fractured and broken fingers from playing basketball and football, but I am proud to be unique and unlike the majority of people. I feel blessed and feel I have an advantage over most people.

So to all double jointed people, I tell them to stay proud, stay strong, work out and strengthen your muscles around those joints you were blessed with. No, you are not deformed. You are the advanced version of human body. --Tim

anon253795
Post 10

I am 23 and only just came across this. I'm the only person I know with this trait. I can also touch my wrist with my thumb and even bend it past my wrist.

anon117248
Post 9

my thumb bends all the way back and all the way forward. Can anyone else's?

anon102245
Post 8

This is so weird. I have hitchhikers thumb and my sister can bend her thumb 25 percent more than me so I think she's double jointed.

anon100656
Post 7

Is hitchhikers thumb associated with any specific culture or nationality?

anon89429
Post 6

It's weird. I studied this in biology at school, and realised I have both. A hitchhiker's on the right, and a regular on the left.

anon76538
Post 4

A 1953 study found that the incidence of the trait in the US was 24.7 percent in white people and 35.6 percent in black people.

anon70522
Post 3

my thumb is really bent and the other is not, so what do i do?

anon26624
Post 1

What is the national percentage of those people with hitchhiker's thumb?

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