What Are the Causes of Pain Below Sternum?

Many conditions can cause pain below the sternum. According to the American College of Gastroenterology, or ACG, abdominal pain can occur throughout the abdomen or in one specific abdominal location or quadrant 1. Some types of abdominal pain manifest in the upper middle part of the abdomen, below the sternum or breastbone. Pain in the upper middle abdomen may be mild, moderate or severe, depending on the cause of the pain and the tissues involved.

Acute Pancreatitis

Acute pancreatitis can cause substernal pain or pain below the sternum 2. According to MayoClinic.com, pancreatitis is the medical term that describes inflammation of the pancreas 2. The pancreas is a long, thin gland and organ that is situated behind the stomach in the upper abdomen. The pancreas generates digestive enzymes and hormones that assist glucose, or sugar, processing in the blood. Pancreatitis can occur as acute pancreatitis or chronic pancreatitis 2. Acute pancreatitis appears suddenly, whereas chronic pancreatitis occurs over many years 2. Common signs and symptoms associated with acute pancreatitis include:

• upper abdominal pain or pain below the sternum
  
• back pain
  
• abdominal pain that is worse after eating
  
• nausea
  
• vomiting
  
• abdominal tenderness 2

Possible causes of acute pancreatitis include alcoholism, cystic fibrosis and a family history of pancreatitis 2.

Lower Lobe Pneumonia

Lower lobe pneumonia can cause pain beneath the sternum. The University of Maryland Medical Center states that pneumonia, including pneumonia in the lower lung lobes, is inflammation of lung tissue caused bacterial or viral infections 3. In some cases, pneumonia may be caused by chemicals that irritate the lungs. The immune system of a healthy individual usually has no difficulty warding off pneumonia infections, although people with compromised immune systems may develop pneumonia more easily. According to the UMMC, avoiding sick people and practicing good hygiene are the most effective ways to prevent lower lobe pneumonia.

Abdominal Muscle Strain

An abdominal muscle strain or a partial tear of the fibers composing the abdominal muscles can cause pain below the sternum. According to the Sports Injury Clinic website, abdominal muscle strains usually occur in the rectus abdominis muscle -- a paired muscle that runs vertically on the front of the abdominal wall 4. These activities are similar in that they all require fast, whole-body movements and rapid changes of direction. Common signs and symptoms associated with abdominal muscle strains include pain below the sternum, tenderness in the affected area and pain when the abdominal muscles are contracted. The Sports Injury Clinic website states that most abdominal muscle strains respond well to conservative care methods such as rest, heat and ultrasound 4.