Why does swelling occur in emily's left knee following the injury?

Swelling in Emily's left knee after the injury is likely due to inflammation caused by the body's response to trauma. When an injury occurs, blood vessels may become damaged, leading to fluid accumulation in the joint area as the body sends white blood cells and other healing substances to the site. This increased fluid can cause swelling, pain, and limited mobility in the affected knee. Additionally, the release of inflammatory mediators contributes to the swelling as part of the healing process.