Definition
Like every joint, the finger joints are also surrounded by a capsule. This capsule can be injured by overstretching, for example if the joint is overstretched too much. This usually happens during sports, e.g. volleyball or basketball, when the ball hits the stretched finger.
Then the joint capsule on the flexion side ruptures. Usually you feel pain immediately and the affected area swells up. If the joint is also dislocated (the head jumps out of the socket), a malposition is visible.
If the joint is bent sideways, the collateral ligaments may also tear in or out. If necessary, a part of the bone can also tear off and a bone splintering can occur. To differentiate between a capsule tear on the finger and an overstretched finger, the editors recommend the following article: Overstretched finger
Causes of a capsule rupture on the finger
The capsules of the finger joints withstand normal loads well. The capsule and the surrounding ligament structures provide stability when bending and stretching the finger. The capsule can tear if the finger joint in question is not designed for a movement.
This happens particularly often during falls, where the fingers or one finger bends backwards, or during sports such as volleyball, where the ball pushes the stretched finger backwards towards the back of the hand. At a certain point the stretching can no longer be carried by the capsule. If there is too much tension on the finger, the joint can no longer bear the longitudinal stretch either.
In most cases, other structures are also injured. If the blood vessels of the finger tear, it can bleed into the joint, which can lead to painful swelling and restriction of movement. In the worst case, a finger joint can dislocate completely, which can lead to a capsule injury to the finger.
Accompanying symptoms with a capsule rupture on the finger
If a torn capsule in the finger is acute, the affected joint usually hurts sharply and is often swollen, and a bruise may also be visible. Since the drainage in this area no longer functions properly, joint fluid is deposited from the injured joint. Sometimes you can also hear a cracking sound when the capsule itself ruptures.
The acute permanent pain becomes stronger if you continue to strain the finger. In most cases, the mobility and function of the joint or finger is also severely restricted, either as a protective function or because structures important for movement have also been injured. If the joint itself is also injured, for example, if the head of the basic limb of the finger jumps out of the socket of the middle limb (dislocation), a malposition can be observed.
