What cause hand to swell after injury?

Swelling is a normal inflammatory response to injury, as it helps to protect the injured area and promote healing. In the case of hand injuries, swelling can be caused by several factors:

1. Inflammation: When the hand is injured, the body's inflammatory response kicks in, causing increased blood flow to the area. This increased blood flow brings with it immune cells and other substances that help to heal the injury, but it can also lead to swelling.

2. Extravasation of fluid: As blood vessels in the injured area dilate (widen), some fluid can leak out of the vessels and into the surrounding tissues. This extra fluid contributes to swelling.

3. Increased permeability of blood vessels: The increased blood flow to the injured area can also cause the blood vessels to become more permeable, meaning that they allow more fluid and proteins to leak out. This also contributes to swelling.

4. Lymphatic obstruction: The lymphatic system helps to drain fluid from the tissues, but if this system is damaged or obstructed by the injury, fluid can accumulate in the hand and cause swelling.

5. Tight bandages or constrictive clothing: If the hand is too tightly bandaged or wrapped, it can restrict blood flow and lymphatic drainage, leading to increased swelling.

6. Gravity: If the injured hand is held down below the level of the heart, gravity can contribute to swelling by pulling fluid into the hand.

In some cases, severe swelling can be a sign of a more serious underlying condition, such as a fracture, dislocation, or infection. If swelling is accompanied by severe pain, deformity, or other concerning symptoms, it is important to seek prompt medical attention.