Pain in your arms is a common symptom with many different causes, from arthritis and overuse injuries like tendonitis to a heart attack.

Skeletal muscle is joined to bones. Its cells contract ... on the back of the upper arm. To raise the forearm, the biceps contract and the triceps relax. To lower the forearm, the triceps contract ...

From your shoulders to your fingers, your arms have many moving parts: joints, bones, muscles, nerves, tendons and ligaments. Mysterious arm pain that seemingly comes out of nowhere can arise if ...