Compartment syndrome happens when excessive pressure builds up inside the body's enclosed muscle space. Compartment syndrome is usually the result of bleeding or swelling following an injury. What is Compartment Syndrome? The hazardously high compartment syndrome pressure impedes blood flow to and from the tissues affected. It can be an emergency that requires surgery to avoid permanent injury. Behind the Muscle in Compartment Syndrome? Organ or muscle groups are organized into areas which are called compartments. The walls of these compartments are formed by strong connective tissue webs, called fascia. Blood or edema (fluid resulting from inflammation or injury) may build up in the compartment following an injury. Fascia's tough walls can't easily expand, and compartment pressure increases, preventing adequate blood flow to tissue inside the compartment. Severe damage to tissue may result, with loss of body function or even death. The legs, arms, and abdomen are more lik...