Introduction
The breastbone (lat. sternum) is the structure in the middle of the bony thorax and consists of 3 bone parts: 1. handle (lat. manubrium sterni), 2. body (lat.
corpus sterni) and 3. sword process (lat. processus xiphoideus). The breastbone is articulated with the ribs (lat.
Costae) and the left and right clavicle (lat. Clavicula). The names of the joints are named after the structures that articulate with each other: Articulatio sternocostale connects sternum and ribs, Articulatio sternoclaviculare connects sternum and clavicle.
The sternum itself is a relatively flat bone and is easily palpable from the outside over its entire length. Together with the ribs, the sternum forms a bony protective cage for many vital organs (heart, lungs, etc. ).
Causes of pain
Pain in or around the sternum can have various causes and can also be variable in its characteristics. Breastbone pain is caused by problems with the heart (cardiac causes), with the musculature, the bone itself or by complaints of other organs. Depending on what the cause of the pain is, more harmless triggers can be differentiated from life-threatening causes.
The sternum can break like any other bone through traumatic force, so the dull to stabbing pain is directly causally related to the fracture. If suspicion exists, an imaging procedure such as X-ray can provide clarity. Other bony structures that can break and cause similar pain are the ribs.
If a fracture is ruled out, a bruised sternum should still be considered, as this also causes severe pain. In addition to the bony structures, pain in the sternum can also be caused by the surrounding muscles. Muscle tension and soreness of the chest and back muscles provoke pain which is mainly motion-dependent or can be aggravated by movement.
A harmless cause that is not considered by most people is heartburn. This is a burning and pulling pain behind the breastbone. The reason for this is the gastric acid that flows unphysiologically from the stomach back into the esophagus (Latin: esophagus) and irritates the wall of the esophagus due to the acidic property (clinical picture: reflux esophagitis).
A change in eating and drinking habits and drug treatment can quickly lead to pain relief. Other causes in the gastrointestinal tract are diaphragmatic hernia, inflammation of the gall bladder and pancreas. The diaphragm is a muscle that separates the organs of the chest from those in the abdomen.
This boundary layer can be permeable due to holes or weak points, so that abdominal organs are pressed into the chest from the bottom to the top. If the stomach is able to move into the chest because of such a malformation, severe chest pain can occur: This is called diaphragmatic hernia. Inflammation of abdominal organs such as the gallbladder or pancreas (lat.
pancreas) causes pain under the breastbone in addition to their classic symptoms. An infection with the “Varizella zoster virus” (VZV; or chickenpox virus infection) can also be a harmless trigger of sternum pain. The result of an initial infection with VZV is chickenpox.
After a second infection with the virus, shingles (herpes zoster) can develop, which is a belt-shaped skin rash. This rash often causes a burning or pulling pain over a dermatome (= skin area supplied by a nerve branch) and in the sternum region. Cardiac causes are less harmless, but there is a clinical picture with reflex heart complaints, which is simply caused by an accumulation of gases in the abdominal cavity, the “Roemheld syndrome”.
Through excessive food intake and bloated food, the resulting gases can put pressure on the heart. This leads to symptoms such as angina pectoris with a feeling of tightness in the chest, shortness of breath and chest pain. Symptoms that can be confused with angina pectoris are sometimes of psychological origin.
Fortunately, this factor is also harmless, but should not be underestimated, as sufferers experience severe pain and an oppressive feeling. In most cases, stress, anxiety and stressful everyday problems are triggers for the psychologically caused sternum pain.It is important to consider the serious and life-threatening triggers. Cardiac (affecting the heart) and pulmonary (affecting the lungs) causes are the most common.
In order to be able to assess the probability of coronary heart disease (CHD) in the case of chest pain, the “Marburg Heart Score” helps. This is a point system of 0-5 points with increasing probability of coronary heart disease (0-1 points: < 1%, 2 points: 5%, 3 points: 25%, 4-5 points: 65%). Criteria are age and sex, known vascular diseases, load dependence of pain, provocation of pain by pressure and the patient’s self-assessment.
The cardinal symptom of coronary heart disease is angina pectoris (“chest tightness”). Triggered by a reduced blood supply to the heart, pressing, constricting and burning pain develops at the sternum. The pain usually lasts only a few minutes and can be triggered by increased strain, cold weather or stress.
Far more severe pain is caused by a myocardial infarction, which is defined as the loss of muscle tissue (lat. myocardium) due to reduced blood flow. As with angina pectoris, the characteristic of sternum pain is accompanied by additional severe pain, also called “pain of destruction”.
This is accompanied by cold sweat, paleness, radiating pain, nausea, dyspnoea (subjectively perceived difficulty in breathing) and dizziness. If a myocardial infarction is suspected, emergency treatment must be initiated immediately, which involves the administration of morphine, oxygen, acetylsalicylic acid (ASA) and nitrates. Another serious trigger of sternal pain is inflammation of the pericardium (pericarditis).
As is typical of inflammation, the pain is accompanied by fever. Breastbone pain in pericarditis is described as stabbing, sharp and cutting and usually lasts for several hours to days. The large arterial vessel that transports the blood of the left heart into our body’s circulation is the aorta.
A pathological splitting of the aortic wall layers (mainly due to tearing of the innermost “tunica intima” layer) is called aortic dissection and leads to severe pain in addition to the previous cardiac causes. The pain is mainly localized in the front thorax at the sternum and can radiate into the back, since the aorta is also located very far back as it passes through the body. The pain is excruciating, stabbing and tearing and usually occurs suddenly.
A dissection can also occur in the esophagus. One cause of esophageal dissection can be reflux esophagitis, which is mentioned among the harmless triggers. The pain is similar in its characteristics and localization to the pain of aortic dissection.
Finally, sternal pain due to pulmonary causes such as pulmonary embolism, pneumonia, spontaneous pneumothorax, bronchial asthma and pulmonary hypertension should be explained as serious triggers of sternal pain. In pulmonary embolism, blood vessels in the lung are blocked by an embolus (= vascular plug made of the body’s own or foreign material). Such an event does not always lead to severe pain comparable to that of angina pectoris, but can only trigger symptoms such as dizziness, tachycardia (=increased heart rate) and fever.
However, severe pulmonary embolisms are usually accompanied by stabbing pain behind the breastbone and in the affected part of the lung for minutes to hours. In addition to the acute occlusion of a pulmonary artery, the pulmonary vessels can be continuously constricted for various reasons. The increased vascular resistance causes the blood pressure in the pulmonary circulation to rise and is then referred to as “pulmonary hypertension”.
The pain is located behind the breastbone and is described as an oppressive feeling of pressure. The pain is usually persistent and can be intensified by exertion. The lung is surrounded by a pleura, the lung membrane.
In between there is the pleural gap, which is not really a real gap, because there is a negative pressure and the pleura is directly adjacent to the lung. If a rupture of the pleura occurs as a result of a traumatic experience or spontaneously, air or even blood enters the gap and the negative pressure is lost. As a result, the lung on the affected side collapses, i.e. it contracts and shrinks. This causes sharply defined pain on the side of the pneumothorax, shortness of breath and a stabbing in the chest.Lastly, pneumonia (inflammation of the lung tissue), caused by a bacterial or viral infection, must be mentioned. The symptoms of a typical pneumonia are cough, high fever, sputum, shortness of breath and stabbing pain in the breastbone.
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