What Organs Are Under Your Right Breast?

Directly beneath your right breast sit several layers of anatomy stacked from the skin inward: the rib cage and intercostal muscles, the lower lobe of the right lung wrapped in its pleural membrane, the muscular diaphragm, and then a cluster of abdominal organs dominated by the liver. The gallbladder, a bend of the large intestine, and part of the right kidney also occupy this region. Because all of these structures share overlapping nerve pathways, pain felt “under the right breast” can originate from surprisingly different sources.

The Chest Wall and the Right Lung

The breast itself has a broad base that overlies roughly the second through sixth ribs, stretching from near the breastbone on the inner side to the midaxillary line on the outer side.¹ Beneath the breast tissue are the pectoralis major and minor muscles, then the ribs and the thin intercostal muscles running between them. These are not just structural scaffolding. The costal cartilages connecting your ribs to the breastbone are a common site of inflammation, and the intercostal muscles themselves can be strained, pulled, or bruised. Many cases of chest-wall pain in the area under the breast turn out to be musculoskeletal rather than organ-related.²

Behind the ribs sits the lower lobe of your right lung, enclosed in the pleura, a thin double-layered membrane that lets the lung glide as you breathe. The pleura is richly supplied with pain-sensing nerves, so conditions like pleurisy (inflammation of the pleura), pneumonia affecting the lower right lobe, or a pulmonary embolism can all produce sharp, sometimes stabbing pain that feels like it is coming from right under the breast. Because the lower lobe extends farther down than most people realize, lung problems can mimic abdominal pain and vice versa.

The Liver

The liver is the largest solid organ in your body and the dominant structure beneath the right breast once you cross below the diaphragm. It fills most of the right upper quadrant of the abdomen, with its right lobe stretching from just below the right nipple line down toward the lower rib margin. Ultrasound measurements of the right liver lobe typically come in around 13 to 15 centimeters from top to bottom, with men averaging a bit larger than women.³ That is a sizable organ pressing right up against the underside of the diaphragm, which is why liver enlargement, hepatitis, or a liver abscess can produce a dull ache or fullness felt in the area beneath the right breast.

The liver itself does not have many pain-sensing nerve fibers in its interior. Most liver pain comes from stretching of the capsule that wraps around it, called Glisson’s capsule. When the liver swells from infection, fatty liver disease, or congestion from heart failure, that capsule gets stretched, and you feel it as a heavy, aching discomfort in the right upper area. Because of its position directly below the diaphragm, liver problems can also irritate the diaphragm and produce referred pain in the right shoulder, a phenomenon we will come back to shortly.

The Gallbladder

Tucked into a shallow groove on the underside of the liver sits the gallbladder, a small pear-shaped sac that stores bile between meals. Its fundus, the rounded bottom end, peeks just past the front edge of the liver and sits roughly where the ninth rib meets the outer border of the right rectus abdominis muscle.⁴ That spot is clinically useful: pressing there while asking someone to breathe in is the basis of Murphy’s sign, a bedside test for gallbladder inflammation.

Gallstones and gallbladder inflammation (cholecystitis) are among the most common reasons people end up in an emergency department with pain under the right breast or in the right upper abdomen. The pain often starts after a fatty meal, builds over 30 minutes to an hour, and can radiate to the right shoulder blade. It is worth knowing that the gallbladder is nestled so close to the liver that imaging studies sometimes have difficulty distinguishing gallbladder wall thickening from adjacent liver tissue without careful technique.

The Hepatic Flexure of the Colon

Your large intestine makes a sharp turn in the right upper abdomen as the ascending colon bends to become the transverse colon. This bend, called the right colic flexure or hepatic flexure because of its proximity to the liver, sits just below the liver and gallbladder.⁵ Trapped gas at this flexure is a surprisingly common and underappreciated cause of pain beneath the right breast. Sometimes called “splenic flexure syndrome” when it happens on the left side, the same gas-trapping phenomenon on the right can produce a sharp, cramping ache that mimics gallbladder or even cardiac pain.

Conditions affecting this part of the colon, including diverticulitis (less common on the right side than the left, but it does happen), colitis, or even a partial bowel obstruction, can generate pain that localizes to the area below the right breast. Because this stretch of colon sits so close to the gallbladder and liver, distinguishing between a colonic source and a hepatobiliary one sometimes requires imaging.

The Diaphragm

Separating the chest cavity from the abdominal cavity is the diaphragm, a broad dome-shaped muscle that is the primary driver of breathing. The right dome of the diaphragm sits slightly higher than the left because the liver pushes it up from below. This means the diaphragm is directly under the right breast area, sandwiched between the lower right lung above and the liver below.

The diaphragm matters for understanding pain in this region because of its nerve supply. The phrenic nerve, which originates from the neck (spinal levels C3 through C5), controls the diaphragm and carries sensory information from the diaphragm, the lower pleura, the pericardium, and parts of the peritoneum covering the liver.⁶ This shared wiring explains a well-known clinical phenomenon: irritation of the diaphragm from below, whether by a liver abscess, gallbladder inflammation, or a subdiaphragmatic collection of blood or pus after surgery, can produce referred pain in the right shoulder or the base of the neck. It also means that a problem originating in the diaphragm itself, such as a diaphragmatic hernia or spasm, can mimic pain from the organs above or below it.

Deeper Structures You Might Not Expect

Behind the liver and colon, in the retroperitoneal space (the area behind the main abdominal cavity), sit the right kidney and the right adrenal gland. The upper pole of the right kidney is roughly at the level of the twelfth rib, which places it in the general neighborhood of the structures beneath the right breast, though it is farther back toward the spine. Kidney stones, a kidney infection (pyelonephritis), or a mass on the right kidney can produce flank pain that wraps around toward the front and is sometimes felt beneath the breast.

The right adrenal gland sits like a cap on top of the right kidney, directly behind the liver. Problems with the adrenal gland are relatively rare, but a large adrenal tumor or hemorrhage into the gland can cause vague right-sided pain that is difficult to localize. Organ volumes in this area are not static over a lifetime: while the liver, kidneys, and spleen do not change much in overall size in adults, adrenal gland volume does increase with age, and the density of these organs gradually decreases.⁷

Why Pain Under the Right Breast Can Be So Confusing

One reason right-sided pain sends people to emergency departments in a state of alarm is that the area beneath the right breast is an anatomical crossroads. Structures from three body compartments converge here: the chest (lung, pleura), the abdomen (liver, gallbladder, colon), and the musculoskeletal system (ribs, cartilage, muscles). The nerve supply to the breast skin comes primarily from the anterior and lateral cutaneous branches of the second through sixth intercostal nerves.⁸ These same intercostal nerves supply the chest wall, parts of the pleura, and the upper abdominal wall. So a single irritated nerve root can produce pain that feels like it is in the breast, the ribs, or the upper abdomen all at once.

Referred pain adds another layer. As noted in the diaphragm section, phrenic nerve irritation from abdominal organs can create shoulder pain.⁹ The reverse can also happen: a thoracic spine problem or a pinched intercostal nerve can produce what feels like abdominal organ pain. Clinicians sometimes describe the right upper quadrant as a “referred pain magnet” because signals from so many different structures converge on the same nerve pathways.

Common Conditions That Produce Pain in This Area

Because so many structures sit beneath or near the right breast, the list of conditions that can cause pain here is long. The most frequent culprits fall into a few broad categories:

Musculoskeletal: Costochondritis (inflammation of the costal cartilage), intercostal muscle strain, rib fracture or bruising, and chest-wall “fibrositis” are among the most common causes of chest-wall pain in general.² These are usually worse with movement, twisting, or pressing on the painful area.
Gallbladder: Gallstones and cholecystitis produce episodic or sustained pain in the right upper quadrant, often with nausea and sometimes fever. The pain typically peaks within an hour and can last several hours.
Liver: Hepatitis, fatty liver disease, liver congestion from heart failure, and less commonly liver abscess can produce a dull, persistent ache or a sense of fullness under the right ribs.
Lung and pleura: Pneumonia of the right lower lobe, pleurisy, and pulmonary embolism can all cause sharp pain that worsens with breathing. A pulmonary embolism is especially treacherous because it can initially present with symptoms similar to pneumonia, including cough and right-sided pleuritic chest pain, sometimes delaying diagnosis.
Colon: Trapped gas at the hepatic flexure, right-sided diverticulitis, inflammatory bowel disease flares, and, rarely, a right-sided colon tumor can produce pain in this region.
Kidney: A kidney stone lodged in the upper right ureter or a right kidney infection typically produces flank pain but can wrap around to the front, overlapping with the area under the right breast.

The character of the pain often gives a clue. Sharp pain that worsens with each breath points toward the pleura or chest wall. Colicky pain that builds and fades suggests the gallbladder or bowel. A deep, constant ache that does not change with breathing or movement leans toward the liver or kidney. But these rules are rough guidelines, not reliable diagnostics, which is why imaging usually becomes necessary.

How Imaging Sorts It Out

When someone presents with pain in the right upper quadrant, the two most commonly ordered imaging studies are ultrasound and CT. Each has strengths. Ultrasound is the first-line tool for evaluating the gallbladder and liver because it is fast, radiation-free, and highly specific for gallstones. CT, on the other hand, has a much broader field of view. In a large retrospective review of over 2,800 emergency-department cases with right upper quadrant pain, ultrasound and CT performed similarly for detecting cholecystitis, with sensitivity in the range of roughly 55 to 61 percent and specificity above 90 percent for both.¹⁰

Where CT pulled clearly ahead was in finding non-gallbladder problems. In about a third of cases where ultrasound was done first and then followed by CT, the CT revealed an acute abnormality that the ultrasound had missed, such as appendicitis, pancreatitis, kidney stones, or a pulmonary embolism in the lung base.¹⁰ The reverse was rare: ultrasound caught something CT missed in fewer than one percent of cases. This does not mean everyone with right-sided pain needs a CT scan. If the clinical picture strongly points to gallstones, ultrasound is the right starting point. But when the diagnosis is unclear, especially when the pain could be coming from the lung, kidney, or bowel rather than the gallbladder, CT gives the broader picture.

How Body Shape and Breathing Change the Map

Anatomy diagrams show organs in fixed positions, but the reality is more fluid. The liver moves up and down with every breath because it is attached to the diaphragm. A deep inhale can push the lower edge of the liver a couple of centimeters below the rib margin, while a full exhale lets it tuck back up behind the ribs. This is why doctors ask you to take a deep breath during an abdominal exam: it brings the liver edge down where they can feel it.

Body habitus matters too. In someone with a tall, thin frame, the liver tends to hang lower and may be palpable even when it is a normal size, a variant sometimes called a Riedel’s lobe. In someone with a shorter, wider torso, the liver sits higher and more protected behind the ribs. Obesity changes the picture further: fat deposits within the liver (non-alcoholic fatty liver disease) can increase liver volume and push adjacent structures around, and a thicker abdominal wall makes physical examination less reliable.

Pregnancy shifts things dramatically. As the uterus grows, it pushes abdominal organs upward and to the sides. The gallbladder and hepatic flexure of the colon get displaced, which is one reason gallbladder disease in late pregnancy can present with pain in unusual locations. The diaphragm gets pushed up as well, reducing lung volume and occasionally making lower-lobe lung problems feel more like upper abdominal pain than chest pain.

The Internal Thoracic Artery and Other Vascular Structures

Running along the inside of the chest wall, just behind the costal cartilages and about a centimeter from the edge of the breastbone, is the right internal thoracic artery. This vessel averages around 185 millimeters in length and roughly 2.3 millimeters in diameter at the second intercostal space.¹¹ It is a critically important artery in cardiac surgery, where it is frequently used as a bypass graft, but in everyday life most people are unaware it exists. Injuries to the chest wall, such as a sternal fracture or a misplaced needle during a procedure, can occasionally damage this artery and cause internal bleeding that presents as pain and swelling under the breast.

The intercostal arteries and veins run along the underside of each rib, feeding the chest wall muscles and skin. While these vessels are small, they bleed persistently when injured, which is relevant if you have had a rib fracture or a chest-wall procedure. The venous drainage of the breast itself feeds into the internal thoracic veins and the axillary vein, creating a vascular network that surgeons must carefully navigate during breast surgery.

When Children’s Anatomy Differs

In children, the organs under the right breast region are the same structures but in different proportions. Every abdominal organ grows in volume throughout childhood, with the liver, kidneys, and spleen all showing a strong positive relationship between organ size and age in pediatric populations.⁷ A child’s liver is proportionally larger relative to body size than an adult’s, which means it extends further below the rib margin and is more easily palpable on exam. Pediatricians routinely feel a liver edge in young children and do not consider it abnormal.

The rib cage in children is also more pliable because the bones have not fully calcified. This means a blow to the right chest wall can injure underlying organs without necessarily fracturing a rib, a pattern that is less common in adults. For the same reason, children with right upper quadrant pain are evaluated with a higher index of suspicion for organ injury even when the chest wall looks intact from the outside.

1
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