The diaphragm, the main muscle involved in breathing, separates the thoracic and abdominal cavities. When a person inhales, it decreases pressure in the lungs and helps expand the rib cage. As with any organ or muscle, the diaphragm is subject to disorders and abnormalities, which come in many different forms and can stem from injury or illness.


Symptoms vary based on the disorder, but may include:

  • Discomfort or difficulty breathing
  • Pain in the chest, shoulder or abdominal area
  • Hypoxemia (a lack of oxygen in the blood)
  • Fewer breath sounds
  • Paralysis, in rare cases


Causes of diseases of the diaphragm vary, but they are usually a result of problems with the anatomy or the neurologic system, such as:

  • Congenital defects, which happen at birth and have no known cause
  • Acquired defects, which occur as the result of an injury, accident or surgery
  • Stroke
  • Muscular disorders, such as muscular dystrophy
  • Multiple sclerosis
  • Thyroid disorders
  • Lupus
  • Radiation therapy
  • Infection
  • Malnutrition
  • Trauma to the muscle or nerve going through the chest to the muscle