Differences Between the Small and Large Intestine- External Differences--Internal Differences-Liver Trauma-Liver Biopsy-Subphrenic Spaces-

Differences Between the Small and Large Intestine
  External Differences

■■ The small intestine has no fatty tags attached to its wall. The large intestine has fatty tags, called the appendices epiploicae.

■■ The small intestine is mobile( but not the duodenum), whereas the ascending and descending parts of the colon are fixed.

■■ The caliber of the full small intestine is smaller than that of the filled large intestine.

■■ The small intestine (with the exception of the duodenum) has a mesentery that passes downward across the midline into the right iliac fossa.

■■ The longitudinal muscle of the small intestine forms a continuous layer around the gut. In the large intestine (with the exception of the appendix), the longitudinal muscle is collected into three bands, the teniae coli

■■ The wall of the small intestine is smooth, whereas that of the large intestine is sacculated

Internal Differences

■■ The mucous membrane of the small intestine has permanent folds, called plicae circulares, which are absent in the large intestine.

■■ The mucous membrane of the small intestine has villi, which are absent in the large intestine.

■■ Aggregations of lymphoid tissue called Peyer’s patches are found in the mucous membrane of the small intestine; these are absent in the large intestine.

Liver Trauma

 Because The liver is a soft organ, it is a friable structure enclosed in a fibrous capsule. Fractures of the lower ribs or penetrating wounds of the thorax or upper abdomen are common causes of liver injury  because Its close relationship to the lower ribs must be emphasized.. Blunt traumatic injuries from automobile accidents are also common, and severe hemorrhage accompanies tears of this organ. Because anatomic research has shown that the bile ducts, hepatic arteries, and portal vein are distributed in a segmental manner, appropriate ligation of these structures allows the surgeon to remove large portions of the liver in patients with severe traumatic lacerations of the liver or with a liver tumor. (Even large, localized carcinomatous metastatic tumors have been successfully removed.)

 

Liver Biopsy

Liver biopsy is a common diagnostic procedure.  And to reduce the size of the costodiaphragmatic recess and the likelihood of damage to the lung the patient must  holding his or her breath in full expiration—a needle is inserted through the right 8th or 9th intercostal space in the midaxillary line. The needle passes through the diaphragm into the liver, and a small specimen of liver tissue is removed for microscopic examination.

 

Subphrenic Spaces

The important subphrenic spaces and their relationship to the liver are described on page 163. Under normal conditions, these are potential spaces only, and the peritoneal surfaces are in contact. An abnormal accumulation of gas or fluid is necessary for separation of the peritoneal surfaces. The anterior surface of the liver is normally dull on percussion. Perforation of a gastric ulcer is often accompanied by a loss of liver dullness caused by the accumulation of gas over the anterior surface of the liver and in the subphrenic spaces.

Ascites- Peritoneal Infection-Internal Abdominal Hernia-Peritoneal Dialysis

Ascites

Ascites an excessive accumulation of peritoneal fluid within the peritoneal cavity. it can occur as a result to hepatic cirrhosis (portal venous congestion), malignant disease (e.g., cancer of the testis), or congestive heart failure. In a thin patient, as much as 1500 mL has to accumulate before ascites can be recognized clinically. In obese individuals, a far greater amount has to collect before it can be detected.

Peritoneal Infection

Infection may gain entrance to the peritoneal cavity through several routes: from the interior of the gastrointestinal tract and gallbladder, through the anterior abdominal wall, via the uterine tubes in females (gonococcal peritonitis in adults and pneumococcal peritonitis in children occur through this route), and from the blood. Collection of infected peritoneal fluid in one of the subphrenic spaces is often accompanied by infection of the pleural cavity. It is common to find a localized empyema in a patient with a subphrenic abscess. It is believed that the infection spreads from the peritoneum to the pleura via the diaphragmatic lymph vessels. A patient with a subphrenic abscess may complain of pain over the shoulder. (This also holds true for collections of blood under the diaphragm, which irritate the parietal diaphragmatic peritoneum.) The skin of the shoulder is supplied by the supraclavicular nerves (C3 and 4), which have the same segmental origin as the phrenic nerve, which supplies the peritoneum in the center of the undersurface of the diaphragm. To avoid the accumulation of infected fluid in the subphrenic spaces and to delay the absorption of toxins from intraperitoneal infections, it is common nursing practice to sit a patient up in bed with the back at an angle of 45°. In this position, the infected peritoneal fluid tends to gravitate downward into the pelvic cavity, where the rate of toxin absorption is slow .

Internal Abdominal Hernia

When  a loop of intestine enters a peritoneal pouch or recess like the lesser sac or the duodenal recesses and becomes strangulated at the edges of the recess. Remember that important structures form the boundaries of the entrance into the lesser sac and that the inferior mesenteric vein often lies in the anterior wall of the paraduodenal recess.

Peritoneal Dialysis

Because the peritoneum is a semipermeable membrane, it allows rapid bidirectional transfer of substances across itself. Because the surface area of the peritoneum is enormous, this transfer property has been made use of in patients with acute renal insufficiency. The efficiency of this method is only a fraction of that achieved by hemodialysis.

A watery solution, the dialysate, is introduced through a catheter through a small midline incision through the anterior abdominal wall below the umbilicus. The technique is the same as peritoneal lavage. The products of metabolism, such as urea, diffuse through the peritoneal lining cells from the blood vessels into the dialysate and are removed from the patient.

Internal Thoracic Artery in the Treatment of Coronary Artery Disease- Lymph Drainage of the Thoracic Wall

Internal Thoracic Artery in the Treatment of Coronary Artery Disease

In patients with occlusive coronary disease caused by atherosclerosis, the diseased arterial segment can be bypassed by inserting a graft. The graft most commonly used is the great saphenous vein of the leg. In some patients, the myocardium can be revascularized by surgically mobilizing one of the internal thoracic arteries and joining its distal cut end to a coronary artery.


 Lymph Drainage of the Thoracic Wall

 The lymph drainage of the skin of the anterior chest wall passes to the anterior axillary lymph nodes; that from the posterior chest wall passes to the posterior axillary nodes. The lymph drainage of the intercostal spaces passes forward to the internal thoracic nodes, situated along the internal thoracic artery, and posteriorly to the posterior intercostal nodes and the para-aortic nodes in the posterior mediastinum.