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What Is a Carpal Boss?

Medically Reviewed by Dan Brennan, MD on April 22, 2021

A carpal boss, also known as a carpometacarpal boss or a bossing, is a bony lump on your wrist where your finger bones meet the bones of your arm. It may be painful, but it will be a firm, immobile lump. Carpal bossing can be mistaken for other, more serious problems like ganglion cysts or tumors, so it’s important to understand the difference.

What Causes a Carpal Boss?

There isn’t one specific cause of a carpal boss. However, there are several conditions that may be related to the formation of a bossing, including:

Atypical bone formation. If your wrist bones formed incorrectly when you were born, then you may have or develop a carpal boss.

Arthritic conditions. Conditions like osteoarthritis can damage the cartilage in your joint, leading bones to rub together and possibly form bone spurs. In the wrist, this may appear as a bossing.

Overuse. If you use your wrist heavily in a repetitive way, you may irritate the joint bone and cartilage and develop a bossing from overuse.

Injuries.Wrist sprains, broken bones in the hand and wrist, and other injuries can all cause you to develop a carpal boss.

Impact of a Carpal Boss on Your Health

Most carpal bosses are completely benign. They lead to a lump on your wrist and nothing more. They can occur on one or both wrists, depending on what caused them.

In most cases, a bossing is not painful, but it can lead to pain or discomfort if it presses against a nerve or rubs against another bone. In this case, you may find it hard to flex your wrist in certain ways or to use your hand like you normally would. If this is the case, your doctor may recommend that you take action to treat the boss to reduce your discomfort.

How to Prevent a Carpal Boss From Affecting Your Health

It’s likely that a carpal boss on one or both wrists won’t impact your health at all. If your bossing isn’t uncomfortable or painful, then it’s safe to leave in place. Your doctor may want to monitor it at your regular physical exam to make sure it hasn’t changed or grown. As long as it doesn’t bother you, you can simply leave it alone.

If your carpal boss does bother you, you have several treatment options. If it causes you discomfort, your doctor may recommend the following treatments to help the joint heal from irritation:

  • Wearing a wrist brace to immobilize your wrist and let it rest
  • Icing your wrist to reduce any swelling, pain, and tenderness
  • ‌Using over-the-counter pain relievers and anti-inflammatory drugs like ibuprofen and aspirin to reduce inflammation and pain
  • ‌ Having a doctor inject steroid into the boss, if other methods don’t relieve the pain and stiffness

‌If none of the above treatment options work to fix your discomfort, or if you dislike the appearance of your boss, you can also consider getting surgery to remove it. This surgery can help prevent the boss from getting worse or causing damage to nearby tendons if it’s in an uncomfortable position.

The goal of carpal boss surgery is to simply remove the bony lump without affecting the surrounding tissue. As with any surgery, you may experience pain and swelling afterward. In most cases, the boss will be entirely removed, and the joint will heal. Some patients might need a second surgery to fuse the joint if the pain doesn’t ease.

When to Go to the Doctor

A carpal boss can be mistaken for a ganglion cyst or a tumor, and vice versa. If you develop a lump on your wrist and you’re not sure what it is, you should talk to your doctor about it. They will be able to help you determine whether you have a bossing or something more serious.

A ganglion cyst has many of the same symptoms as a boss. They both create lumps on the wrist that are usually painless, but they may cause pain if they press on nerves or tissue. They can both make it hard to move your wrist in certain ways if they’re in a difficult location.

However, while a boss is a hard, immobile lump of bone, a ganglion cyst is more likely to be softer and possibly able to move slightly if you press on it gently. 

Tumors in your wrist are also likely to be soft and may be mobile, but there are many possible ways for wrist and hand tumors to present. If you are concerned about your wrist lump, you should talk with your doctor to make sure you know what to expect.

Show Sources

Sources:‌

American Society for Surgery of the Hand: “Carpal Boss,” “Wrist or Hand Tumor.”

‌Cleveland Clinic: “Have a Carpal Boss?”

Journal of Clinical and Diagnostic Research: “Diagnosis and Treatment of Symptomatic Carpal Bossing.”

Journal of Hand Surgery: “The Preliminary Results of Treatment of Symptomatic Carpal Boss by Wedge Joint Resection, Radial Bone Grafting and Arthrodesis with a Shape Memory Staple.”

‌Mayo Clinic: “Ganglion Cyst."

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