Give yourself a thumbs-up—then take a closer look.
If the tip of your thumb bends back toward your knuckle at more than a 50-degree angle, you might have what’s casually called hitchhiker’s thumb. This nickname refers to distal hyperextensibility, which simply means you have extra-flexible ligaments. It may make for a fun party trick, but could it also be a signal for something more?
We asked doctors to explain.
Hitchhiker’s thumb causes
Hitchhiker’s thumb can be “a harmless anatomy quirk localised to the thumb,” says assistant clinical professor of physical medicine and rehabilitation Dr Isabel Huang. But in some cases, it can be a clue to broader joint hypermobility, she adds. This includes conditions such as hypermobility spectrum disorder or hypermobile Ehlers-Danlos Syndrome (hEDS).
“Some people with hitchhiker’s thumb have very flexible joints throughout the body, while others don’t,” says internal medicine associate program director Dr Raj Dasgupta. The trait can also run in families, suggesting a genetic component.
Hitchhiker’s thumb hasn’t been widely studied, so prevalence data is limited. However, a 2012 study found that 32.3% of a sample group of 310 people had the trait—15.5% were male and 16.8% were female.
Associated conditions
Hitchhiker’s thumb isn’t always linked to an underlying condition—but in some cases, it can be associated with the following:
Hypermobility/hEDS
Joint hypermobility occurs when joints move beyond their normal range due to unusually loose ligaments, explains Dr Dasgupta. This can cause pain, instability, and in some cases, be part of a connective tissue disorder like hEDS.
People with hEDS often experience a “myriad of other complaints,” says Dr Huang, including anxiety, depression, insomnia, asthma, acid reflux, hives, postural orthostatic tachycardia syndrome (POTS), dislocations, back pain, jaw pain, constipation, nausea, vomiting and diarrhoea. That said, “just being hypermobile does not mean you have hEDS,” she stresses. Diagnosis should come from a physician experienced with hEDS.
Arthritis
Over-flexible joints, including the thumb, can lead to early-onset arthritis, says Dr Dasgupta. You may also notice reduced grip strength or frequent strains. “It’s usually more of an annoyance than a serious issue, but for some, it can affect everyday tasks,” he says. In some cases, developing hitchhiker’s thumb later in life could also be related to arthritis.
Diastrophic dysplasia
Hitchhiker’s thumb may also appear in people with diastrophic dysplasia, a rare condition that impacts cartilage and bone development. People with this condition may also have short limbs, club foot or a cleft palate.
Ageing with hitchhiker’s thumb
If your hitchhiker’s thumb is part of broader joint hypermobility, it may increase your risk of developing joint pain, arthritis or tendon issues as you age, says Dr Dasgupta. “If it’s related to a connective tissue disorder, it might also come with chronic pain, fatigue or cardiovascular concerns,” he adds.
Hitchhiker’s thumb treatment
Since hitchhiker’s thumb on its own isn’t a medical condition, Dr Dasgupta says it doesn’t usually need treatment. But if it causes discomfort or interferes with function, there are ways to manage it. Strengthening the muscles around the joint, working on grip strength and avoiding repetitive strain can help. “Bracing or taping can offer extra support if needed,” he adds.
If you suspect your hitchhiker’s thumb could be a sign of something more complex, speak with your doctor for personalised guidance.
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