The anatomical snuff box (or the radicular fold), is a long, triangular depression shaped on the outer side of your hand just below the first joint of your thumb. It’s located at the upper part of the carpal bones above the pinky finger. It’s best seen when the middle finger is depressed. In olden days, this depression has been used to hold ground tobacco before inhaling through the nose. Today, it’s not used that way any more.
If you were to blow into the anatomical snuff box, the air would go directly into your stomach where your blood supply is greatest. But what happens if you don’t blow in the right way? The air goes back up the esophagus – back to the heart. This is why it’s so important to blow your nose gently – because if you don’t, you run the risk of creating the reverse flow of blood, from your lower extremities to your heart.
If you do create an anatomical snuff box when you blow your nose, there’s a good chance one of two things will happen: either a newscaphoid fracture will result, or your carpi radialis will break in two. (The words “carpi radialis” are Latin for “long bone” and “radial bone” – which is exactly what your thumb actually is.) When your carpi radialis breaks in two, it’s known as carpi recurrent adhesion. (pronounced “rek-sigh-ee-uh”)
In a normal anatomical snuff box, the tissue that acts as a finger tendon, or tendon sheath, will wrap around the inside of your thumb. The tissue sheath will run diagonally up your thumb (toward your pick) and then wrap around the top side of your index finger. This is what creates the second problem with a normal anatomical snuff box. In this case, the tendon sheath doesn’t wrap properly around the finger – creating a loop of weakened tendons and causing acute pain.
If you have an outstretched hand with your thumb bent at the elbow, and you blow your nose – you run the risk of creating a shearing tension across the tendon sheath running between your thumb and index finger. Because you’re bending your thumb, it’s possible to get a higher force through this area than if you were not. (You can use a tennis or golf ball to help you “hammer” the tendons in your outstretched hand – the same action – with your thumb outstretched. The same effect applies to the lateral (outside) part of your forearm.)
This means that when you bend your hand, you run the risk of deforming your median nerve. Most of us don’t like to think about our nerves, but when you have one damaged by a trauma (not from a football injury, although that is a common source of injury for athletes), it can be very serious. The median nerve supplies the voice in your body and is responsible for your singing, swallowing, and wind-sucking capabilities. In addition, it provides the nutrients needed by your immune system. And, without it, your body cannot function properly.
When you blow your nose – which happens more than you think – you run the risk of damaging your radial artery. The radial artery is the blood vessel carrying oxygenated blood from the heart to your brain. If it’s cut or damaged, you can have brain or cardiac arrest, and death may occur within seconds. You should be aware that the anatomical snuff box only cuts the blood vessels that are directly under your skin, so if there are tendons directly under your skin, they will not be cut, too.
So, we have established that the anatomical snuff box is ineffective in terms of treating tennis elbow symptoms. How can you prevent the tendon sheath from being cut? Very simple. What you want to do is strengthen your thumb (and the muscles that comprise it) so that you have a stronger grip. One exercise that strengthens the muscles of your thumb and forefinger is the “overhand pick.”