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.