Pain under the left shoulder blade can be a symptom of a heart event, which raises a serious concern. While the heart can project pain to this area, the majority of discomfort in the left shoulder blade is related to less severe, non-cardiac issues. However, the potential for a cardiac connection is significant enough that everyone should know how to distinguish between a simple muscle ache and a medical emergency. Understanding the mechanism behind this phenomenon and recognizing accompanying symptoms is crucial.
Understanding Referred Pain
A problem in the heart can be felt in the shoulder blade due to referred pain. This neurological phenomenon occurs because internal organs, such as the heart, lack dedicated sensory nerves that travel directly to the brain to signal pain. Instead, nerves carrying pain signals from the heart converge with nerves from other areas, including the left arm, jaw, and upper back, as they enter the spinal cord.
These converging nerve fibers travel to the same area of the spinal cord, primarily the T1 to T4 segments. When the heart experiences distress, such as a lack of oxygen during a heart attack, the brain mistakenly interprets the strong pain signals as originating from superficial areas like the shoulder blade or arm. The brain is confused by this signal crossover, projecting the visceral pain onto the body’s surface. This mechanism explains why shoulder blade pain may be the only symptom a person experiences, without any chest discomfort.
Recognizing Heart-Related Pain
Heart-related pain, often from angina or a heart attack, typically presents as a deep pressure, squeezing, or fullness rather than a sharp, localized stab. This sensation may begin in the chest but frequently radiates to the jaw, neck, left arm, or between the shoulder blades. The pain is not positional, meaning it does not change when you move, press on the area, or take a deep breath.
The presentation of cardiac pain often differs significantly between men and women. While men are more likely to experience the classic “elephant sitting on the chest” pressure, women often report more atypical symptoms. For women, pain in the upper back or between the shoulder blades can be a primary symptom of a heart attack, sometimes without chest pain.
This back pain in women may be accompanied by extreme fatigue, nausea, vomiting, or a feeling of indigestion. Other accompanying signs for both sexes include sudden shortness of breath, cold sweat, lightheadedness, or a sense of dread. If the shoulder blade discomfort occurs during physical exertion and subsides with rest, it may signal angina (reduced blood flow to the heart). Pain that persists or worsens is a sign of a more serious event.
Other Common Sources of Pain in the Area
The majority of pain felt under the left shoulder blade is not heart-related but stems from musculoskeletal or nerve issues. The rhomboid muscles, which sit beneath the shoulder blade and connect it to the spine, are a frequent source of discomfort. Strain from poor posture, prolonged sitting, or repetitive motions can lead to a dull, persistent ache that often improves with movement or massage.
Pain originating from the cervical or thoracic spine can also refer to the shoulder blade. A pinched nerve, perhaps from a bulging or herniated disc in the neck, can cause a sharp, burning, or tingling sensation that travels to the shoulder blade. Unlike heart pain, this type of nerve pain is aggravated by specific neck movements, coughing, or sneezing.
Less common but serious non-cardiac causes must also be considered. An aortic dissection, a tear in the body’s main artery, typically causes sudden, severe, tearing pain in the chest or upper back that requires immediate emergency care. Other visceral issues, like a pulmonary embolism (a clot in the lung), can cause sudden, sharp pain between the shoulder blades alongside severe shortness of breath.
Immediate Action: When to Call 911
If left shoulder blade pain is accompanied by red flag symptoms, call emergency services immediately. The threshold for urgent action is when the pain is sudden, intense, or coupled with symptoms like crushing chest pressure, severe shortness of breath, or fainting. Any new, unexplained pain occurring with cold sweating, dizziness, or nausea should be treated as a medical emergency.
Do not attempt to drive yourself or a loved one to the hospital; medical staff can begin life-saving treatment immediately upon the ambulance’s arrival. While waiting for emergency responders, rest quietly in a seated position and remain calm. If you are not allergic and have been directed by the emergency dispatcher, chewing a standard 325 mg aspirin can help thin the blood and limit damage to the heart muscle.