Pain of the upper arm on the left outer side
Pain that radiates outwards into the left upper arm or is localized there at certain points can theoretically be caused by a blocked coronary vessel. In order to differentiate between a heart attack and a more muscular problem, the medical history is particularly important. Here it is found out whether the patient has accompanying complaints such as shortness of breath or pressure on the chest, whether he has had a heart attack before or whether heart diseases are known to him or his family.
Finally, the question should not be omitted as to whether the patient has done heavy work with his left arm before the onset of the complaints or whether he has performed an unusual movement. This would rather indicate a local cause in the sense of muscle hardening or strain. The deltoid muscle (Musculus deltoideus) runs along the left side of the upper arm.
This muscle is responsible for the lateral movement of the arm. If this movement was performed more frequently before the onset of symptoms, this does not indicate cardiac involvement as the triggering cause. Nerves that run in the area of the left-sided upper arm can also be compressed by muscles or bone protrusions and lead to painful pulling of the left outer upper arm.
The examiner can use relatively simple methods to find out whether the left-sided, outer upper arm pain is more of a muscular problem or a heart problem. First, the patient is asked to move the arm forward, backward and sideways by himself. If the pain can be intensified in this way, this indicates a muscular cause.
In most cases, the deltoid muscle is affected. In the next step, the examiner will ask the patient to lift the arm laterally against resistance (usually the examiner presses against the hanging arm while the patient tries to lift the arm). If the patient then indicates an increase in pain, it is more likely to be a muscle problem. In most cases, this is due to a pulled or overstrained deltoid muscle.
