Carpometacarpal bossing

Overview
Carpometacarpal bossing is a condition in  the  small, immovable mass of bone called the carpometacarpal joint and occurs when this joint becomes swollen or bossed. The carpometacarpal joint is usually found at the base of the second and third metacarpal bones at the point where they meet the small bones of the wrist. This condition can result in sensitivity in the immediate area and/or an unsightly bulge on the back of the hand. In most cases, the boss does not result in any injury or further problems, but in some cases, the patient may feel pain, aching, or even possibly a slight lack of mobility in the wrist joint. Often, this condition will be mistaken for a ganglion cyst due to its location and external appearance.

A carpometacarpal boss may exist from birth or may be the result of a trauma or injury in the affected area. There are also indications that those with careers involving repetitive movements in the hands and fingers may develop this condition. Typically, this condition will begin to show itself in the 3rd or 4th decade.