Angina pectoris literally means "pain in the chest". It results from arteriosclerosis of the arteries that supply the heart muscle itself, i.e., the coronary arteries. Arteriosclerosis is the hardening of arteries and arterioles due to thickening of the fibrous tissue, and the consequent loss of elasticity. Due to the lack of required expansion, the arteries are unable to carry extra blood to the heart muscle at the time of stress when the heart is beating more vigorously. Deprived of oxygen the heart muscle experiences constricting pain.