The thoracic cavity, or chest, is a protected space framed by the rib cage, which provides a bony shield for the soft tissues and organs within. The body’s internal geography is divided by the diaphragm, a large, dome-shaped muscle that separates the upper chest region from the lower abdominal region. While the thoracic cavity contains organs like the windpipe, esophagus, and major blood vessels, the most prominent structure on the right side is the largest organ of the respiratory system.
The Major Respiratory Organ
The primary organ occupying the right side of the chest cavity is the right lung, which performs the function of gas exchange, taking in oxygen and releasing carbon dioxide. This lung is notably wider and slightly shorter than the left lung due to the presence of the liver directly beneath it. Anatomically, the right lung is divided into three distinct sections, known as lobes: the superior, the middle, and the inferior lobes.
These lobes are separated by fissures, which allow the lung to expand and contract efficiently during breathing. The lung’s surface is covered by the visceral pleura, a smooth membrane that continues to form the parietal pleura lining the inner chest wall. A lubricating fluid between these layers prevents friction as the lung moves against the ribs during respiration.
The Large Organ Under the Ribcage
Directly inferior to the right lung and the diaphragm is the liver, the largest solid organ in the body. Although technically an abdominal organ, its substantial size means its upper surface is tucked up under the dome of the diaphragm and protected by the lower right ribs.
The liver’s primary roles involve filtering blood to remove harmful substances and regulating the body’s internal chemistry. It also produces bile, a fluid necessary for breaking down and absorbing fats in the digestive process.
Non-Visceral Structures and Referred Pain
The right chest area is composed of several supporting structures, including the ribs, the intercostal muscles, and a network of nerves. The ribs form a protective cage, and the intercostal muscles assist the diaphragm in the mechanical act of breathing. The diaphragm itself is a sheet of muscle that separates the chest and abdominal cavities.
Pain experienced in this area does not always originate from the chest structures themselves, a phenomenon known as referred pain. This occurs when nerve signals from an internal organ are mistakenly interpreted by the brain as coming from a different, more superficial location. For example, the gallbladder, situated beneath the liver, or the esophagus can cause discomfort felt near the right rib cage.
Causes of Discomfort in the Right Chest Area
Discomfort on the right side of the chest can stem from issues related to the respiratory, musculoskeletal, or digestive systems. Musculoskeletal problems are common, such as a muscle strain from physical activity or Costochondritis, which is inflammation of the cartilage connecting the ribs to the breastbone. Pain from these causes often worsens with movement, deep breathing, or when pressure is applied to the area.
Respiratory conditions affecting the right lung, such as pneumonia or pleurisy, can cause sharp pain that intensifies with a deep breath or cough. Pneumonia involves inflammation of the lung’s air sacs, while pleurisy is the inflammation of the pleural lining.
Digestive issues frequently manifest as right-sided pain, particularly those involving the liver or gallbladder. Conditions like gallstones or inflammation of the liver, such as hepatitis, can cause pain that may be felt in the upper right abdomen and sometimes radiate up into the lower chest.