Pain in the left arm can be a sign of an impending heart attack, according to Mayo Clinic. A physical problem, such as tennis elbow, may also be the root cause of the pain.
Pain in the left arm is usually caused by heart trouble, but this is not always the case, notes HealthCentral. However, left arm pain from heart complications is indicative of a myocardial infraction, which takes place when the heart does not receive sufficient oxygen due to blood flow constriction. The restriction can cause pain in different areas, such as the lower jaw, left arm or chest. Left arm pain from heart trouble is linked to the nerves. The connection between the nerves and heart causes mixed pain signals, but the true pain occurs when the heart undergoes cardiac arrest. The discomfort may begin in the chest but channels from the face to the arms, particularly the left arm.
Chest pain may take the form of pressure or a squeezing sensation, explains Healthgrades. Other symptoms include nausea, excessive sweating, vomiting, swallowing difficulties or an abnormal heart rhythm. Left arm pain may also stem from a sprain of the acromioclavicular joint, which is connected to the shoulder blade and collarbone, claims HealthCentral. This type of injury may occur from an accident or fall.