The most common causes of arm pain and numbness include an injury or a disturbance of blood flow to the arm. Injuries can include fractures, sprains, stains, and nerve problems. A change in blood flow to the arm can occur with any of these injuries and with certain medical conditions.
An injury to the muscles or the supporting tendons and ligaments which connect the upper and lower arm bones can cause pain throughout the arm. Injury to the shoulder or neck area can also bring about arm pain. Damage to the brachial plexus, a nerve cluster in the arm pit area, for example, can bring about pain which travels down the arm and even into the hand.
Pressure on the nerves in the neck area can produce radiating pain which spreads to bring about pain and numbness in the arms. Nerve pressure can occur with bulging or herniated discs, tumors, swelling issues, and some infection processes. In addition to pain and numbness, symptoms of nerve irritation or damage can include a burning sensation or the feeling of small needles being jabbed continually into the arm.
When there is a change in blood flow, arm pain and numbness can be experienced. Atherosclerosis, commonly referred to as hardening of the arteries, is a condition where the diameter of a blood vessel gets smaller. Compression of the blood vessels can also happen if the tissues surrounding it are inflamed or swollen. The result is a slowing of the flow of blood. Pain in the chest and left arm is a condition called angina. This pain, similar to a heart attack, is triggered by a reduction of blood flow to the heart.
Another change in blood flow can occur with a medical warning sign called a transient ischemic attack, or TIA. This is sudden drop in the blood flow to the brain, and it can produce one-sided arm pain and numbness. Though the resulting throbbing and tingling arm sensation is temporary, it is the body's way of alerting the person of a possible stroke.
Certain medical conditions may cause arm pain and numbness. Diabetes can cause neuropathy or damage to the nerves. Another source of nerve damage where the body's immune system destroys the nerve's protective covering is multiple sclerosis. Rheumatoid arthritis causes joint changes and can bring about arm pain when the joints or connection of bones in the arm are affected. Lupus can damage the joints and blood vessels causing pain or numbness all over the body, including the arm.