The area directly below your sternum is centered on a small piece of bone called the xiphoid process, and just behind it sits the epigastric region of your abdomen, home to your stomach, the left lobe of your liver, part of your pancreas, and the spot where your diaphragm anchors to your skeleton. Pain here is one of the most common reasons people show up at a doctor’s office or emergency room, and what makes it tricky is the sheer number of organs crowded into the space. The cause can be as minor as a bruised bit of cartilage or as urgent as a cardiac event disguising itself as indigestion.
The Xiphoid Process and What Sits Behind It
Your sternum, or breastbone, is not one solid slab. It has three parts: the broad manubrium at the top, the long body in the middle, and the xiphoid process at the very bottom. The xiphoid is a small, somewhat pointed projection of cartilage that gradually turns to bone over the course of your life. In young adults it is still largely cartilaginous; by middle age it has usually ossified and fused to the sternal body. You can feel it if you press your fingers into the soft spot where your lower ribs meet in front.
Directly behind and below the xiphoid lies the epigastric region. If you drew a triangle between the lower edges of your ribcage and the bottom of the breastbone, that triangle is roughly where the epigastrium sits. Within it you will find the body of the stomach curving to the left, the left lobe of the liver extending from the right, the tail of the pancreas running deep and horizontally, and the beginning of the duodenum connecting the stomach to the rest of the small intestine. The diaphragm, the large dome-shaped muscle that drives your breathing, attaches in part to the xiphoid process and spreads across the top of this region, separating the chest cavity from the abdomen. The celiac trunk, a major arterial branch off the aorta, supplies blood to many of these organs from just behind the stomach.
Because so many structures are packed into a compact space, pain felt “right below the sternum” can originate from the xiphoid itself, any of the organs just described, or even from the heart sitting just above and behind the breastbone. Sorting out the source is the central challenge.
When the Xiphoid Itself Is the Problem
One of the most overlooked causes of pain in this exact spot is xiphoidalgia, sometimes called xiphodynia. It is pain arising from the xiphoid process or the joint where it meets the sternal body. The condition is considered rare, but “rare” may partly reflect underdiagnosis: many clinicians do not think to press on the xiphoid during an exam, so the tenderness goes unnoticed and the patient gets worked up for gastric or cardiac disease instead.
Xiphoidalgia can follow direct trauma to the chest, like a steering-wheel impact or a fall. It can also develop from repeated minor stress, such as heavy lifting or prolonged coughing. The hallmark is localized tenderness when you press directly on the xiphoid, and the pain sometimes radiates into the chest, the back, or the upper abdomen. It is described as a debilitating condition that involves pain at the xiphoid or structures anchored to it.1PubMed Central. Treatment and Management of Xiphoidalgia Treatment usually starts with anti-inflammatory medications and avoiding activities that aggravate the area. In stubborn cases, a local corticosteroid injection at the xiphoid can help, and in very rare situations the xiphoid process is surgically removed.
Stomach and Esophageal Causes
The stomach sits right behind the xiphoid, so gastric problems are among the first suspects when you feel pain in this zone. Gastritis, peptic ulcers, and acid reflux all produce epigastric discomfort that patients frequently describe as burning, gnawing, or a dull ache. The pain from a gastric ulcer classically worsens after eating, while a duodenal ulcer tends to hurt when the stomach is empty and improves with food, though these textbook patterns do not hold for everyone.
A hiatal hernia, where the upper part of the stomach pushes upward through the diaphragm’s esophageal opening, is another common contributor. When a hiatal hernia is large enough or complicated by an ulcer at the junction between the esophagus and the stomach, the result can be progressive epigastric pain along with difficulty swallowing. In such cases, weakened function of the lower esophageal sphincter allows gastric acid to reflux upward, which worsens both the pain and the ulceration.2PubMed Central. Hiatal Hernia With Ulcer at the Gastroesophageal Junction Presenting With Progressive Dysphagia and Epigastric Pain: A Case Report The practical takeaway is that substernal pain accompanied by trouble swallowing, regurgitation, or a sour taste in the mouth points toward the esophagus or the gastroesophageal junction rather than the heart.
Functional dyspepsia is worth mentioning too. This is chronic or recurring pain and discomfort centered in the upper abdomen for which no structural cause can be found on endoscopy or imaging. It is extremely common and can persist for months or years. The mechanisms are not fully understood, but heightened sensitivity of the stomach’s nerves, delayed gastric emptying, and low-grade inflammation of the duodenum all seem to play a role. Treatment involves acid-suppressing medications, sometimes low-dose antidepressants that modulate gut nerve signaling, and dietary adjustments.
When the Heart Mimics a Stomach Problem
This is the scenario that keeps emergency physicians on edge. Pain just below the sternum can be the sole symptom of a cardiac problem, and patients and doctors alike sometimes mistake it for indigestion. The phenomenon has been recognized for nearly a century. A classic clinical account described an elderly man whose only complaint was a sense of oppression in the lower sternal and epigastric region when he carried a heavy basket. He would pause, bring up a little gas, feel completely relieved, and walk home. He had no chest pain, no anxiety, only what he called “indigestion and gas.” The diagnosis turned out to be myocardial disease.3JAMA. Myocardial Disease and Its Gastric Masquerades
The reason the heart can produce epigastric pain is that the inferior wall of the heart sits on top of the diaphragm, very close to the stomach. An inferior myocardial infarction, a heart attack affecting the bottom of the heart, commonly refers pain downward into the epigastrium rather than into the left arm or jaw. Patients may report nausea, belching, or a heavy feeling in the upper belly with no classic chest tightness at all. If you are over 50, have risk factors for heart disease, and develop unexplained substernal or epigastric discomfort especially with exertion, it is worth considering a cardiac cause even in the absence of “textbook” heart attack symptoms.
Acute pericarditis, inflammation of the sac surrounding the heart, can go even further down the misleading path. The pain of pericarditis usually centers on the front of the chest and behind the sternum, but it can radiate forcefully into the abdomen. In some documented cases the abdominal pain, cramps, distention, tenderness, and vomiting were so severe that patients were taken to surgery for a suspected abdominal emergency before the true diagnosis was recognized.4JAMA. Acute Idiopathic Pericarditis Simulating Acute Abdominal Disease A useful clue to pericarditis is that the pain tends to worsen when you lie flat and improve when you lean forward, a pattern that stomach and intestinal problems rarely follow.
Vascular Causes You Would Not Expect
Two vascular conditions can produce pain right below the sternum, and both are easy to miss because they are uncommon and mimic more familiar diagnoses.
Median arcuate ligament syndrome, often abbreviated MALS, occurs when a fibrous band of the diaphragm compresses the celiac trunk where it branches off the aorta. That compression reduces blood flow to the stomach, liver, and spleen, and it can also irritate the celiac nerve plexus that runs alongside the artery. The result is upper abdominal pain that characteristically worsens after eating. Nausea, vomiting, food avoidance, and weight loss round out the picture, closely mimicking other forms of reduced blood supply to the gut.5PubMed Central. Treatment of median arcuate ligament syndrome via traditional and robotic techniques MALS is estimated to affect roughly 2 per 100,000 people and is more common in women.6PubMed Central. Another Sherlock Holmes Mystery: Abdominal Pain Explained by Median Arcuate Ligament Syndrome In some patients the celiac trunk also develops atherosclerotic narrowing on top of the external compression, compounding the problem.7American Journal of Case Reports. Chronic Post-Prandial Epigastric Pain Associated with Median Arcuate Ligament Syndrome and Atherosclerosis of the Celiac Trunk in An Elderly Woman: A Case Report Treatment can involve surgical release of the ligament, sometimes with stenting of the artery.
A ruptured abdominal aortic aneurysm is in a different league altogether. This is a life-threatening emergency in which the wall of the aorta, the body’s largest artery, balloons out and tears open. Most ruptures occur in the section of the aorta that runs through the abdomen, and they classically produce sudden severe pain, a drop in blood pressure, and a pulsatile mass that can sometimes be felt in the belly.8Postgraduate Medical Journal. Ruptured abdominal aortic aneurysm: a surgical emergency with many clinical presentations The pain often starts in the back or flank but can be felt in the epigastric area too. What makes this dangerous from a diagnostic standpoint is that the presentation varies widely; not every patient shows the classic triad, and the condition can initially be confused with kidney stones, a perforated ulcer, or pancreatitis. Anyone with sudden, severe upper abdominal pain and lightheadedness needs emergency evaluation.
Epigastric Pain During Pregnancy
In pregnancy, pain below the sternum takes on an additional layer of urgency. While heartburn from acid reflux is extremely common in the second and third trimesters due to a growing uterus pushing the stomach upward, a specific and dangerous condition called HELLP syndrome can present with right upper quadrant or epigastric pain. HELLP stands for hemolysis, elevated liver enzymes, and low platelets, and it is a severe variant of preeclampsia. The epigastric pain comes from liver swelling and reduced blood flow caused by damage to the cells lining small blood vessels.
Pain in the right upper quadrant or epigastric area is the most common symptom of HELLP syndrome, reported in about 65% of cases, often accompanied by nausea and vomiting in about 35% and headaches in about 30%.9PubMed Central. A typical presentation of previable HELLP syndrome: a case report The condition can appear as early as the second trimester, and because the initial symptoms overlap with ordinary pregnancy-related heartburn or stomach upset, it is sometimes caught late. Any pregnant person experiencing persistent upper abdominal pain, especially with swelling, visual changes, or a headache that will not go away, should be evaluated promptly. Blood pressure measurement and basic blood work can usually identify HELLP syndrome quickly.
How Doctors Sort Through the Possibilities
Given how many organs can generate pain in the same small area, the diagnostic approach relies heavily on combining physical examination findings with targeted testing. A study of patients presenting to the hospital with acute abdominal pain found that on multivariate analysis, abdominal guarding, an elevated white blood cell count, a fast heart rate, and vomiting were the clinical variables most reliably associated with significant underlying pathology.10PubMed Central. What clinical and laboratory parameters determine significant intra abdominal pathology for patients assessed in hospital with acute abdominal pain? In plain terms, a tense abdomen that hurts when you press on it, combined with signs of infection or physiological stress, raises the odds that something serious is going on.
For imaging, standard abdominal ultrasound and upper endoscopy (where a camera is passed into the stomach) are the most common first-line tools. However, endoscopic ultrasound, which combines the camera with an ultrasound probe on the tip of the scope, has shown promise as a single test that can evaluate both the lining of the stomach and the structures outside the gut in one session. A head-to-head comparison found that endoscopic ultrasound matched the combined diagnostic rate of standard endoscopy plus external ultrasound, and it proved superior for visualizing the pancreas and detecting chronic pancreatitis and bile duct stones.11Gastrointestinal Endoscopy. EUS compared with endoscopy plus transabdominal US in the initial diagnostic evaluation of patients with upper abdominal pain The advantage is efficiency: one procedure replaces two, which can also reduce costs.12PubMed Central. Endoscopic ultrasound, the one-stop shop for abdominal pain?
An electrocardiogram is a standard part of the workup when upper abdominal pain could conceivably be cardiac, particularly in older adults or anyone with cardiovascular risk factors. Blood tests for cardiac enzymes (troponin), liver enzymes, lipase for the pancreas, and basic markers of inflammation and infection fill in the rest of the initial picture. CT scanning comes into play when vascular emergencies like aortic aneurysm rupture are suspected or when the initial round of tests leaves the diagnosis unclear.
Pain After Cardiac or Upper Abdominal Surgery
People who have undergone open-heart surgery through a median sternotomy, where the breastbone is split down the middle, can develop a specific complication called a subxiphoid incisional hernia. This occurs when tissue or part of an organ pushes through a weakness in the area where the lower end of the sternotomy meets the abdominal wall. The hernia can cause a palpable bulge and aching pain right below the sternum, especially with straining or coughing.
Several factors raise the risk of this complication, including obesity, diabetes, chronic lung disease, surgical site infections, and the need for repeat operations. Left-sided heart failure and low cardiac output after surgery also contribute, likely because poor blood flow impairs wound healing at the incision site.13PubMed Central. Subxiphoid Incisional Hernia Following Cardiac Procedures: A Narrative Review If you have had a sternotomy and notice a new bulge or aching below the lower end of your scar, particularly months or years after the original surgery, it is worth mentioning to your surgeon.
An Anatomical Quirk Worth Knowing About
A small percentage of people have a hole in their sternum that they are born with and never know about. Called a sternal foramen, this opening results from the incomplete fusion of the cartilaginous segments that form the breastbone during fetal development. It shows up in roughly 2.5% to nearly 14% of the population depending on the study, and it is almost always located in the lower third of the sternal body, close to the xiphoid process, with an average diameter of about 6.5 millimeters.14PubMed Central. A Comprehensive Review of the Sternal Foramina and its Clinical Significance
A sternal foramen by itself does not cause pain and is not a disease. The reason it matters is procedural safety: acupuncture needles, sternal bone marrow biopsies, and sternal wire closures during heart surgery all assume the breastbone is a solid shield in front of the heart. A needle or wire that passes through an unsuspected foramen can enter the pericardium or even the right ventricle. Radiologists and surgeons who are aware of the variation can spot it on a CT scan and adjust their approach. For the average person, the foramen is a harmless footnote in their anatomy, but it is a good example of how the area right below the sternum holds more structural variety than most people would guess.
Red Flags That Warrant Immediate Attention
Most episodes of pain below the sternum turn out to be acid-related or muscular and resolve with over-the-counter treatment or time. But certain features should prompt you to seek emergency care rather than waiting it out:
- Sudden onset: Pain that arrives abruptly and at full intensity, rather than building gradually, raises concern for a vascular event, a perforation, or a cardiac cause.
- Exertional pattern: Discomfort that reliably comes on with physical effort and eases with rest is a hallmark of reduced blood flow to the heart, even when the pain is felt in the belly rather than the chest.
- Lightheadedness or fainting: Feeling faint, especially with abdominal pain, suggests falling blood pressure, which can mean internal bleeding or a cardiovascular emergency.
- Rigid abdomen: A belly that feels board-like and involuntarily tenses when touched indicates peritoneal irritation, often from a perforation or significant inflammation.
- Vomiting blood or black stool: These are signs of gastrointestinal bleeding, which can originate from ulcers, varices, or other lesions in the upper digestive tract.
- Pregnancy with persistent pain: Upper abdominal pain in the second or third trimester that does not behave like typical heartburn warrants blood pressure and lab checks to rule out preeclampsia or HELLP syndrome.
Pain below the sternum occupies an anatomical crossroads. The stomach, the esophagus, the heart, the diaphragm, the pancreas, major blood vessels, and the xiphoid itself all converge in a space you could cover with both hands. That density is what makes the symptom both common and diagnostically challenging. Paying attention to the character of the pain, what brings it on, what relieves it, and what other symptoms travel with it gives clinicians the best clues for narrowing down the source.