Breastbone Pain and Causes of Retrosternal Pain (Behind Sternum)

The breast bone, also known as the sternum, is a flat bone located in the middle of the thorax (chest) and serves two important functions in the body. Firstly, the breast bone protects the vital organs lying behind it, primarily the heart and airways, and secondly, it serves as a central point where the ribs and shoulder bones (clavicle) connect and articulate.

The breast bone can be divided into three distinct parts :

1. Manubrium
2. Body
3. Xiphoid process

Breast bone pain is a common symptom that is experienced at frequent intervals in life and may be harmless in most cases. However, persistent pain or pain that is increasing in intensity or frequency, should be investigated by a medical doctor.

Breast bone pain is usually experienced and described as pain in the bone, under the breast bone or to the side of the bone. Pain may range from sharp and stabbing sensations to mild soreness or a bruised feeling.

In some cases there are reports of a popping sternum which is a clicking or cracking noise from the breastbone  joints that may be present along with pain, tenderness and swelling. Although referred to as the breast bone, the sternum does not lie under the breast but rather in between the breast, extending above (manubrium) and through the cleavage in women.

Causes of Breast Bone Pain

• Heartburn or reflux is the most common cause of a burning pain along and under the breast bone as a result of esophagitis. Gastroesophageal reflux (GERD) may also result in episodes of severe sharp pains in the chest and is often mistaken for a myocardial infarction (heart attack) during these episodes. Other types of esophagitis may also cause breastbone pain.
• Fractures of the sternum is rare but may occur in car accident injuries due to the impact with the steering wheel.
• Joint pain at the points where the shoulder bone (1) and ribs (2) articulate with the breast bone can be due to inflammatory joint disorders like arthritis although this is uncommon. More commonly, joint pain may be due to strain during impact or when exercising, specifically weight lifting. Joint pain is usually felt on either side of the breast bone. Costochondritis and Tietze’s syndrome are two common causes of breastbone pain due to the inflammation of the costal cartilage and joint.
• Muscle pain, specifically of the pectoral muscles, may cause breast bone pain as they attach at this site. Muscle strain is the most common cause and results typically in a bruised or sore pain, often described as an ache. The intercostal muscles, which lie between the ribs, may also cause breast bone pain and these muscles may get strained during constant deep and forced breathing, particularly in respiratory disorders like emphysema and asthma.
• Cardiac conditions like coronary artery disease, angina, myocardial infarction (heart attack), myocarditis and pericarditis are serious causes of pain under the breast bone.
• Respiratory causes of breast bone pain include bronchitis, bronchiectasis and tracheitis. Tuberculosis and pneumonia may also cause pain under the breast bone although these conditions usually affect the sides of the chest around the area of the lungs.
• Psychological conditions like panic and anxiety attacks may cause a perceived pain under the breast bone which may be related to an increased heart rate (palpitations), heartburn or psychogenic pain (perceived pain).
• Surgery of the organs within the thoracic (chest cavity) may require separation of the bones of the chest. Cardiothoracis or open heart surgery may be the cause of long term pain in or on the sides of the breast bone even after the wounds heal.
• Other conditions, which are not common causes of breast bone pain, may include acute pancreatitis, hiatal hernia, stomach ulcers and causes of excessive belching or upper middle abdominal pain. Cancer of the lungs, airways, lung abscess and sarcoidosis may also cause breast bone pain.

Pain Behind Sternum

Pain behind the sternum (retrosternal pain) is often associated with cardiac conditions, however, the more common causes are related to acid reflux and related gastrointestinal conditions. Rarely, retrosternal pain may be a consequence of referred pain from neighboring structures, especially those in the abdominal cavity as is seen with gastritis, peptic ulcer, gallstones and pancreatitis.

If retrosternal chest pain presents with shortness of breath, dizziness and severe weakness, then cardiovascular conditions needs to be considered. Retrosternal chest pain with coughing, particularly a productive cough, may be attributed to respiratory conditions. Cardiovascular conditions may be life-threatening. The onset of retrosternal chest pain, especially when associated with shortness of breath, sweating, radiation of pain to the left arm, jaw, neck or abdomen, dizziness, fainting, nausea and/or vomiting, needs to be immediately assessed by a medical professional.

Organs Behind the Breastbone

It is important to consider the structures that lie in the central part of the chest cavity, behind the breastbone.

• Thymus gland (remnants)
• Heart
• Great blood vessels (portion originating or ending in the heart)
• Esophagus
• Trachea
• Bronchi (origin)
• Vertebrae (cervical and thoracic)

However, this may be too simplistic of an overview of the anatomy in this region. Many organs and tissues overlap slightly into the central part of the chest cavity and may partly lie in the area behind the breastbone. This includes the mediastinal lining, pericardium, pleura and lungs. Expansion of the chest cavity with breathing (inspiration) and subsequent contraction (expiration) can also cause slight changes in anatomical position that may also account for retrosternal pain.

Causes of Chest Pain Behind the Breastbone

Pain being the sternum most likely arises from disease of the organs behind the breastbone. However, it is also important to note that sometimes the pain may not originate from this area. Instead it may arise elsewhere and radiate or refer to the region behind breastbone. Therefore evaluating the pain alone in trying to isolate the cause can often be inaccurate. Instead other symptoms and even the patient’s medical history should be taken into account in order to more accurately identify a possible cause. This can then be confirmed with various investigations to reach a final diagnosis.

Gastrointestinal

These are conditions affecting the throat, esophagus (gullet) and upper stomach which may present with chest pain behind sternum. Most often it is diseases, damage and irritation of the esophagus that is responsible for retrosternal chest pain. The most common of these is gastroesophageal reflux disease (GERD) where acid flows backward from the stomach into the esophagus. This causes heartburn.

• Acid reflux (acute)
• GERD / Gastroesophageal reflux disease (chronic)
• Esophagitis
• Esophageal spasms
• Esophageal ulcer
• Esophageal tear
• Foreign body

Cardiovascular

The heart and great blood vessels are the most important structures in the chest cavity lying behind the breastbone. Therefore pain behind the sternum always raises the concerns of damage or disease of the heart and the root of these large blood vessels. Cardiovascular conditions of this nature can be rapidly life threatening and therefore has to be taken seriously.

• Angina
• Myocardial infarction (heart attack)
• Pericarditis
• Aortic dissection
• Pulmonary embolism
• Atrial fibrillation
• Mitral valve prolapse
  

Respiratory

The lungs and lower air passages lie within the thoracic cavity. The trachea runs down the center and then branches out to either side via the bronchi. This divides into smaller airways and carries air to the air sacs of the lungs. Diseases of the trachea, bronchi and medial portions of the lung are therefore more likely to contribute to retrosternal chest pain. Furthermore, the ling around the lungs known as the pleura may also be a source of the pain.

• Tracheitis
• Pleuritis
• Cancer (airway, lung pleura), especially if there is spread to the mediastinal lymph nodes.

Tumors

Tumors, whether benign (non-cancerous) or malignant (cancerous), may also be the cause of pain behind the breastbone. It is not the most common cause but needs to be considered when other causes have been excluded, there are other symptoms indicative of a tumors and there are relevant findings on imaging studies like chest x-rays, CT scans or an MRI.

• Mediastinal lymphadenopathy, often in lung cancer and mesothelioma
• Thymoma (thymus gland)

References

1. Sternal Fracture. Medscape
2. Chest Pain. MSD Manual

Last updated on August 23, 2018.