It's a common misconception that muscle injuries only happen to athletes -- not so. A pulled arm muscle, also known as an arm strain, can happen to anyone. This type of injury typically occurs when you're engaged in strenuous physical activity involving one or both of your arms. An arm strain involves mild to severe tearing of muscle or tendon fibers in one of your arm muscles. Signs and symptoms of a pulled arm muscle help distinguish this painful injury from other arm ailments.
Pain and Tenderness
Pain is the hallmark symptom of a pulled arm muscle. Sudden pain typically occurs at the time of the injury, when the muscle or tendon fibers tear while the muscle is actively engaged. For example, a biceps strain commonly occurs when lifting a heavy object, either during weight training or while performing everyday tasks. The pain typically decreases when your arm is at rest, but quickly flares when using the injured muscle. The pain is focused over the area of the tear, which is typically tender if you press on it. Pain associated with an arm strain varies, depending on the severity of the tear.
Swelling and Deformity
A pulled arm muscle often causes swelling at the site of the tear. This swelling occurs as part of the body's normal response to the injury, and might reflect localized bleeding associated with the tear. Skin bruising, however, is relatively uncommon with a nontraumatic arm strain because any bleeding that occurs is deep within the arm. In cases of a moderate to severe arm muscle or tendon tear, you might notice a lump deformity. This sign is most likely with a complete tear, or rupture, of an arm muscle.
A mild arm strain usually causes no loss of muscle strength. However, a moderate to severe tear characteristically leads to weakness of the affected muscle and a reduce range of motion of the arm. The combination of pain and weakness can make everyday activities difficult, such as washing your hair, brushing your teeth and loading or unloading groceries. Avoiding arm movement due to pain can also cause weakness in muscles near the site of the injury due to lack of use.
Warnings and Precautions
A mild arm strain usually heals within a few weeks, if the injured muscle is rested. However, if your pain fails to improve or is of moderate intensity, see your doctor as soon as possible. A variety of arm ailments lead to signs and symptoms similar to that of a pulled arm muscle, so it's important to get an accurate diagnosis. Seek immediate medical care if you sustain a traumatic arm injury, or if you experience any warning signs and symptoms, including:
-- arm or hand numbness or tingling
-- severe or rapidly worsening pain
-- inability to move your upper or lower arm
Reviewed and revised by: Tina M. St. John, M.D.