The abdominal cavity extends from the lower border of the ribs to the pelvis. The abdominal wall is made up of muscle, layers of connective tissue, and fat and is lined by a thin double layered membrane called the periosteum. The abdominal cavity contains all of the organs of the digestive system and the genitourinary system. Research Abdominal Cavity
Appendicitis is a disease which became well-known during the 19th century. It consists in inflammation of the vermiformappendix of the large intestine, a somewhat wormlike hollow body, several inches long, projecting from and opening into the intestine, but closed at the opposite extremity. In appendicitis proper the inflammation begins in the appendix and spreads to neighbouring parts, and thus the disease is sometimes included under the term perityphlitis, which more strictly belongs to inflammation connected with the caecum, and not necessarily with the appendix.
Appendicitis is usually set up by more or less hard bodies that become lodged in the appendix, especially particles of food that have not been sufficiently masticated. The disease may be very slight, lasting for a day or two, and accompanied with some pain and sickness; or it may take a severe and violent form, the result being death in a few hours. Death may also occur at a longer interval, when an abscess forms, which bursts into the abdominal cavity. There are also cases of chronic and of relapsing appendicitis, and in these removal of the organ is necessary. Some surgeons resort to removal of the appendix in all cases of the disease. The usual symptoms are such as pain in the belly, especially low down on the right side, fever, constipation, nausea, and vomiting. Early remedies were such as rest in bed, hot fomentations or poultices applied to the belly, with opium to relieve pain, food being given in small quantities, in the fluid form and hot. During the 20th century surgery became the preferred treatment, the appendix being cut out by a surgeon. Research Appendicitis
The colon is the central part of the large intestine. Extending from the cecum to the rectum, it is descriptively subdivided into four parts: the ascending, the transverse, the descending, and the sigmoid colon. The ascending colon extends upward from the cecum to lead into the transverse portion. The transverse extends across the abdominal cavity from the end of the ascending part to lead into the descending section of the colon. The descending colon extends from the end of the transverse colon to the sigmoid colon. The sigmoid colon connects the end of the descending colon to the rectum. The rectal and sigmoid sections are often referred to as the rectosigmoid. Research Colon
The diaphragm is the primary muscle responsible for respiration. Connected to the abdominal wall, the lumbar vertebra, the lower ribs, the sternum, and the pericardium of the heart by tendinous tissue, the thin diaphragm creates a partition between the thoracic and abdominal cavity. The
diaphragm forms a domed structure, and when the diaphragm muscle contracts, it lowers to a more flattened arrangement. This flattening causes a vacuum in the thoracic cavity and pressure in the abdominal cavity. The vacuum is filled by the expanding lung tissue and inhaled air. The pressure on the lower viscera are helpful in childbirth and in pushing fecal matter through the lower intestinal tract for expulsion. When the diaphragm relaxes to its domed structure, the air is exhaled and the lungs contract. Though the intercostal and abdominal muscles are also used in respiration, during sleep, it is primarily due to contractions of the diaphragm. The diaphragm is supplied by the inferior and superior phrenic arteries and the musculophrenic artery. It is innervated phrenic nerve. Research Diaphragm
The horizontal fissure divides the middle and upper lobes of the right lung and the upper and lower lobes of the left lung. The right and left lung feature fissures which divide the overall structures into smaller lobes. The left lung has one horizontal fissure which divides it into two lobes (upper and lower). The right lung has one horizontal fissure and one oblique fissure, dividing the right lung into three lobes (upper, middle, and lower). Because of this third lobe, the right lung is larger than the left, extending further down in the abdominal cavity. The right and left lung are each enclosed in a pleural sac and are separated by the mediastinum, a membrane which extends from the vertebral column in back to the sternum in front. Research Horizontal Fissure
A laparotomy is a surgical incision through the abdominal walls into the abdominal cavity, such as a Caesarean operation. The use of laparotomy, as an exploratory surgery technique, has decreased sharply with advances in medical imaging and the direct-viewing technique known as endoscopy. Research Laparotomy
The obturator foramen is the large opening in each pubis. These openings admit blood vessels and nerves from the abdominal cavity to the inside of the upper legs. Research Obturator Foramen
The omentum is a long fold of the peritoneum. It is loaded with fat and lies in front of the bowels in the abdominal cavity. It protects the bowels and keeps them warm. Research Omentum
The pelvis creates the basin of the lower abdominal cavity. It is formed by three separate bones which become fused: the ilium, the ischium, and the pubis. The ilium is the broad, wing-like segment which features the wide, slightly concave surfaces of the back and sides of the pelvic girdle. The ischium forms the smaller, lower, portion which bears the weight of the body while sitting. The pubis creates an archway in the front of the basin which allows the urethra, blood vessels, and nerves to pass through the pelvic girdle to the external genitalia and lower body. The pelvis articulates with the sacrum in the back (and thereby connects to the rest of the vertebral column) and to the legs through the ball- and-socket joint formed by the two acetabula of the
pelvis and the head of each femur. Research Pelvis
The peritoneum is a complex, serous membrane lining the lower abdominal cavity. Its function is to provide a lubricating surface against which the viscera may move so that they are not damaged by friction. In the male body, the peritoneum is predominately a closed, sac-like structure, while in the female, the fallopian tubes penetrate the peritoneum. The peritoneum contains the lesser cavity at the upper abdomen, near the stomach and transverse colon. The duplicating folds of the peritoneum are called omenta. The greater omentum is the largest of these and hangs down from the stomach over the small intestine. The greater omentum is composed of highly vascularized and innervated fatty tissue, protecting the lower viscera from shock and infection. Research Peritoneum
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Abdominal Cavity
