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.
The renal arteries are paired arteries that supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle.
The periaortic lymph nodes are a group of lymph nodes that lie in front of the lumbar vertebrae near the aorta. These lymph nodes receive drainage from the gastrointestinal tract and the abdominal organs.
The renal veins in the renal circulation, are large-calibre veins that drain blood filtered by the kidneys into the inferior vena cava. There is one renal vein draining each kidney. Each renal vein is formed by the convergence of the interlobar veins of one kidney.
In human anatomy, the inferior mesenteric artery (IMA) is the third main branch of the abdominal aorta and arises at the level of L3, supplying the large intestine from the distal transverse colon to the upper part of the anal canal. The regions supplied by the IMA are the descending colon, the sigmoid colon, and part of the rectum.
The superior thoracic aperture, also known as the thoracic outlet, or thoracic inlet refers to the opening at the top of the thoracic cavity. It is also clinically referred to as the thoracic outlet, in the case of thoracic outlet syndrome. A lower thoracic opening is the inferior thoracic aperture.
The renal circulation supplies the blood to the kidneys via the renal arteries, left and right, which branch directly from the abdominal aorta. Despite their relatively small size, the kidneys receive approximately 20% of the cardiac output.
The inferior phrenic veins drain the diaphragm and follow the course of the inferior phrenic arteries;
The inferior thyroid veins appear two, frequently three or four, in number, and arise in the venous plexus on the thyroid gland, communicating with the middle and superior thyroid veins. While the superior and middle thyroid veins serve as direct tributaries to the internal jugular vein, the inferior thyroid veins drain directly to the brachiocephalic veins.
The inferior phrenic artery is a bilaterally paired artery of the abdominal cavity which represents the main source of arterial supply to the diaphragm. Each artery usually arises either from the coeliac trunk or the abdominal aorta, however, their origin is highly variable and the different sites of origin are different for the left artery and right artery. The superior suprarenal artery is a branch of the inferior phrenic artery.
The middle suprarenal artery is a paired artery in the abdomen. It is a branch of the aorta. It supplies the adrenal gland.
The inferior suprarenal artery is a paired artery that supplies the adrenal gland. It usually originates at the trunk of the renal artery before its terminal division, but with many common variations. It supplies the adrenal gland parenchyma, the ureter, and the surrounding cellular tissue and muscles.
The adrenal arteries are arteries in the human abdomen that supply blood to the adrenal glands.
The suprarenal plexus is formed by branches from the celiac plexus, from the celiac ganglion, and from the phrenic and greater splanchnic nerves, a ganglion being formed at the point of junction with the latter nerve.
The phrenic plexus accompanies the inferior phrenic artery to the diaphragm, some filaments passing to the suprarenal gland.
The superior suprarenal artery is an artery in the abdomen. It is a branch of the inferior phrenic artery, itself a branch of the aorta. It supplies the adrenal gland.
The following outline is provided as an overview of and topical guide to human anatomy:
