The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal organs, and is composed of a layer of mesothelium supported by a thin layer of connective tissue. This peritoneal lining of the cavity supports many of the abdominal organs and serves as a conduit for their blood vessels, lymphatic vessels, and nerves.
The pleural cavity, pleural space, or interpleural space is the potential space between the pleurae of the pleural sac that surrounds each lung. A small amount of serous pleural fluid is maintained in the pleural cavity to enable lubrication between the membranes, and also to create a pressure gradient.
The thoracic diaphragm, or simply the diaphragm, is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the most important muscle of respiration, and separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity: as the diaphragm contracts, the volume of the thoracic cavity increases, creating a negative pressure there, which draws air into the lungs. Its high oxygen consumption is noted by the many mitochondria and capillaries present; more than in any other skeletal muscle.
In human anatomy, the abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta.
A side stitch is an intense stabbing abdominal pain under the lower edge of the ribcage that occurs during exercise. It is also called a side ache, side cramp, muscle stitch, or simply stitch, and the medical term is exercise-related transient abdominal pain (ETAP). It sometimes extends to shoulder tip pain, and commonly occurs during running, swimming, and horseback riding. Approximately two-thirds of runners will experience at least one episode of a stitch each year. The precise cause is unclear, although it most likely involves irritation of the abdominal lining, and the condition is more likely after consuming a meal or a sugary beverage. If the pain is present only when exercising and is completely absent at rest, in an otherwise healthy person, it does not require investigation. Typical treatment strategies involve deep breathing and/or manual pressure on the affected area.
In anatomy, the epigastrium is the upper central region of the abdomen. It is located between the costal margins and the subcostal plane. Pain may be referred to the epigastrium from damage to structures derived from the foregut.
In human anatomy, the internal thoracic artery (ITA), also known as the internal mammary artery, is an artery that supplies the anterior chest wall and the breasts. It is a paired artery, with one running along each side of the sternum, to continue after its bifurcation as the superior epigastric and musculophrenic arteries.
The lesser omentum is the double layer of peritoneum that extends from the liver to the lesser curvature of the stomach, and to the first part of the duodenum. The lesser omentum is usually divided into these two connecting parts: the hepatogastric ligament, and the hepatoduodenal ligament.
The abdomen is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. The area occupied by the abdomen is called the abdominal cavity. In arthropods, it is the posterior tagma of the body; it follows the thorax or cephalothorax.
The septum transversum is a thick mass of cranial mesenchyme, formed in the embryo, that gives rise to parts of the thoracic diaphragm and the ventral mesentery of the foregut in the developed human being and other mammals.
In the human mouth, the incisive foramen is the opening of the incisive canals on the hard palate immediately behind the incisor teeth. It gives passage to blood vessels and nerves. The incisive foramen is situated within the incisive fossa of the maxilla.
The greater omentum is a large apron-like fold of visceral peritoneum that hangs down from the stomach. It extends from the greater curvature of the stomach, passing in front of the small intestines and doubles back to ascend to the transverse colon before reaching to the posterior abdominal wall. The greater omentum is larger than the lesser omentum, which hangs down from the liver to the lesser curvature. The common anatomical term "epiploic" derives from "epiploon", from the Greek epipleein, meaning to float or sail on, since the greater omentum appears to float on the surface of the intestines. It is the first structure observed when the abdominal cavity is opened anteriorly.
The vitelline veins are veins that drain blood from the yolk sac and the gut tube during gestation.
The round ligament of the liver, ligamentum teres or ligamentum teres hepatis is a ligament that forms part of the free edge of the falciform ligament of the liver. It connects the liver to the umbilicus. It is the remnant of the left umbilical vein. The round ligament divides the left part of the liver into medial and lateral sections.
The central tendon of the diaphragm is a thin but strong aponeurosis situated slightly anterior to the vault formed by the muscle, resulting in longer posterior muscle fibers.
The coronary ligament of the liver refers to parts of the peritoneal reflections that hold the liver to the inferior surface of the diaphragm.
The left triangular ligament is a large peritoneal fold. It connects the posterior part of the upper surface of the left lobe of the liver to the thoracic diaphragm.
A portacaval anastomosis or portocaval anastomosis is a specific type of circulatory anastomosis that occurs between the veins of the portal circulation and the vena cava, thus forming one of the principal types of portasystemic anastomosis or portosystemic anastomosis, as it connects the portal circulation to the systemic circulation, providing an alternative pathway for the blood. When there is a blockage of the portal system, portocaval anastomosis enables the blood to still reach the systemic venous circulation. The inferior end of the esophagus and the superior part of the rectum are potential sites of a harmful portocaval anastomosis.
Diaphragmatic rupture is a tear of the diaphragm, the muscle across the bottom of the ribcage that plays a crucial role in breathing. Most commonly, acquired diaphragmatic tears result from physical trauma. Diaphragmatic rupture can result from blunt or penetrating trauma and occurs in about 0.5% of all people with trauma.
In human anatomy, the liver is divided grossly into four parts or lobes: the right lobe, the left lobe, the caudate lobe, and the quadrate lobe. Seen from the front – the diaphragmatic surface – the liver is divided into two lobes: the right lobe and the left lobe. Viewed from the underside – the visceral surface – the other two smaller lobes, the caudate lobe and the quadrate lobe, are also visible. The two smaller lobes, the caudate lobe and the quadrate lobe, are known as superficial or accessory lobes, and both are located on the underside of the right lobe.
