per i posteri, tratto dal Gray "The anatomical bases of clinical practice"
The greater omentum
The greater omentum is the largest peritoneal fold and hangs inferiorly from the greater curvature of the stomach. It is a double sheet: each sheet consists of two layers of peritoneum separated by a scant amount of connective tissue. The two sheets are folded back on themselves and are firmly adherent to each other. The anterior sheet descends from the greater curvature of the stomach and first part of the duodenum. The most anterior layer is continuous with the visceral peritoneum over the anterior surface of the stomach and duodenum and the posterior layer is continuous with the peritoneum over the posterior wall of the stomach and pylorus. The anterior sheet descends a variable distance into the peritoneal cavity and then turns sharply on itself to ascend as the posterior sheet. The posterior sheet passes anterior to the transverse colon and transverse mesocolon. It is attached to the posterior abdominal wall above the origin of the small intestinal mesentery and anterior to the head and body of the pancreas. The anterior layer of the posterior sheet is continuous with the peritoneum of the posterior wall of the lesser sac. The posterior layer is reflected sharply inferiorly and is continuous with the anterior layer of the transverse mesocolon. The posterior sheet is adherent to the transverse mesocolon at its root and is often known as the gastrocolic ligament, which is the supracolic part of the greater omentum. In early foetal life the greater omentum and transverse mesocolon are separate structures, and this arrangement sometimes persists. During surgical mobilization of the transverse colon, the plane between the transverse mesocolon and greater omentum can be entered opposite the taenia omentalis, and the greater omentum can be separated entirely from the transverse colon and mesocolon if required. Access into the lesser sac can be obtained via this approach if the upper part of the posterior sheet of the greater omentum is then divided. This gives a relatively bloodless plane of entry for surgical access to the posterior wall of the stomach and to the anterior surface of the pancreas. The greater omentum is continuous with the gastrosplenic ligament on the left, and on the right it extends to the start of the duodenum. A fold of peritoneum, the hepatocolic ligament, may run from either the inferior surface of the right lobe of the liver or the first part of the duodenum to the right side of the greater omentum or hepatic flexure of the colon.
The right border of the greater omentum is occasionally adherent to the anterior surface of the ascending colon down as far as the caecum: its peritoneal layers are not continuous with the peritoneum over this part of the colon. A thin sheet of peritoneum referred to as Jackson's membrane may run from the front of the ascending colon and caecum to the posterolateral abdominal wall and may merge with the greater omentum. It often contains several small blood vessels. Occasionally, a band passes from the right side of the ascending colon to the lateral abdominal wall near the level of the iliac crest. It has been called the 'sustentaculum hepatis' but plays no role in the support of the liver. Other folds between the ascending colon and posterolateral abdominal wall may divide the right lateral paracolic gutter into several small recesses. Less commonly the greater omentum is adherent to the anterior surface of the left colon; very occasionally it extends to the level of the sigmoid colon.
When the undisturbed abdomen is opened, the greater omentum is frequently wrapped around the upper abdominal organs. Only rarely is it evenly dependent anterior to the coils of the small intestine, although this is the disposition which is frequently illustrated. It is usually thin and cribriform, but it always contains some adipose tissue and is a common site for storage of fat in obese individuals, particularly males.
Between the two layers of the anterior fold of the greater omentum, close to the greater curvature of the stomach, the right and left gastroepiploic vessels form a wide anastomotic arc. Numerous vessels are given off from the arc and extend the full length of the omentum. This supply appears to exceed the metabolic requirements of the omentum, and perhaps reflect the role the greater omentum may play in peritoneal disease processes. The greater omentum is highly mobile and frequently becomes adherent to inflamed viscera within the abdominal cavity. This action may help to limit the spread of infection and the omentum may provide a source of well-vascularized tissue to take part in the early reparative process. It contains numerous fixed macrophages, which are easily mobilized. These may accumulate into dense, oval or round visible 'milky-spots'.
purtroppo sto avendo a che fare con l'anastasi, e ho scaricato il gray in inglese, visto che la nuova edizione è uscita lo scorso settembre e non mi fidavo, dato che l'anastasi è comunque giudicato dai più come soddisfacente...ma se tutto il testo fosse chiaro come questo estratto consiglio a chi verrà dopo di lasciar marcire l'anastasi nelle librerie e andare di gray U_U
Schema circolazione arteriosa
Artropodi
Anatomia (riassunto)