If your nighttime ritual involves holding your phone to your face and scrolling through Twitter or watching a couple (dozen) YouTube videos, you may notice your arm hurts the next day.
That pain has a name: “cell phone elbow,” medically known as ulnar nerve entrapment or cubital tunnel syndrome. Simply put, keeping an arm flexed for hours while holding a phone can put some serious strain on the ulnar nerve. This stress can stretch and constrict the nerve while limiting its blood supply.
What’s happening to your arm?
The ulnar nerve runs the length of the arm, from neck to little finger, and it’s the largest nerve in the human body not protected by muscle or bone. It gives sensation to your pinky and ring fingers and the portion of your palm beneath those digits. The most common place for this nerve to bind up is in that little groove on the outside of your elbow—the area you may know as your “funny bone.”
This can happen whenever your body remains in a flexed, static position for too long. “Motion is life,” says chiropractor Rudy Gehrman, noting that our relatively immobile lives make us susceptible to repetitive stress injuries like strained or pinched nerves. That stress creates microtraumas as muscles, ligaments, and tendons all start to stretch or compress in ways they are not supposed to, he explains.
In the case of cell phone elbow, continually flexing your arm stretches the ulnar nerve, which can cause tingling or numbness in your outer fingers. Left untreated, it can lead to permanent nerve damage and muscle degradation.