A bruise or ecchymosis is a collection of blood that lies within body tissues or cavities. A bruise occurs when capillaries bleed under the skin whilst the overlying skin remains intact causing bluish-black or darkening discolouration. A haematoma is a deeper bruise. It is a collection of blood that lies within body tissues or cavities.
Larger blood vessels such as arteries may lead to more profuse or prolonged bleeding and thus deeper or bigger haematomas.
Predisposition to haematomas may be as a result of liver disease, clotting disorders or blood vessel defects.