Abdominal symptoms are common. Mastery of the abdominal examination is essential since judgments based primarily on history and physical examination are the basis for differential diagnosis and selection of laboratory and imaging studies to confirm a diagnosis. An accurate and thorough history is essential to delineate the specific characteristics and sequence of the patient's symptoms. Frequent repetition of the abdominal exam and correlation with the patient's symptoms are essential. Correct assessment of abdominal findings requires familiarity with anatomic pathology and pathophysiology. Surgeons must excel in abdominal examination because their findings influence the decision to operate.
In the supine position, the abdominal cavity is a shallow oval basin with a rigid W-shaped bottom of vertebral column and back muscles. Heavy flank muscles constitute the long sides and the diaphragm and pelvic floor muscles close either end. The brim is formed by the lower rib margins at one end, and the pubes and ilia at the other. The cover is formed by the flat muscles and fascia of the anterior abdominal wall, reinforced by two parallel bands of rectus muscles attached to the ends of the basin.
The abdominal viscera are solid or hollow. The solid viscera are the liver, spleen, kidneys, adrenals, pancreas, ovaries, and uterus. Most of these organs retain their characteristic shapes and positions as they enlarge. Many are clustered under the protecting eaves of the lower ribs. The hollow viscera are the stomach, small intestines, colon, gallbladder, bile ducts, fallopian tubes, ureters, and urinary bladder. They are normally not palpable, unless distended by gas, fluid or solid masses.
Two systems have been used to describe abdominal topography (Fig. 9–1). Most physicians prefer the simpler division into quadrants by an axial and a transverse line through the umbilicus; we use that plan here.
Topographic Divisions of the Abdomen.On the left are the regions of the abdomen as defined in the Basle Nomina Anatomica terminology. Most of the nine regions are small, so that enlarged viscera and other structures occupy more than one. On the right is a simpler plan with four regions; it is preferred by most clinicians and is employed in this book. Many occasions arise when the quadrant scheme needs supplementing by reference to the epigastrium, the flanks, or the suprapubic region.
The alimentary system is responsible for converting ingested foodstuffs into biologically available nutrients and fuels, and for eliminating solid wastes while maintaining a barrier to an enormous variety of microorganisms, parasites, and toxic molecules. This is a complex process involving ingestion, mastication, bulk transport, storage, mechanical disruption, mixing, and digestion of ingested food and absorption of nutrients coordinated with production, storage, transport, and carefully timed release of digestive enzymes and bile acids. The alimentary system starts at the mouth and ends at the anus. The oral cavity and pharynx, were discussed previously. Most of the alimentary system is located in the abdomen, extending from the gastroesophageal junction at or near the diaphragmatic hiatus to the anus. Normal motility and digestion are dependent upon coordination of muscular and secretory functions via local and systemic neural and endocrine mechanisms. The bowel is a muscular tube suspended by a mobile mesentery (stomach, small intestine, cecum, transverse and sigmoid colon) or anchored to the posterior abdominal wall (duodenum, ascending and descending colon) or pelvic floor (rectum). It is susceptible to intraluminal obstruction at narrow points (gastroesophageal junction, pylorus, ileocecal valve), to extraluminal obstruction by compression anywhere in its course, and to twisting or kinking when suspended on a mesentery (especially the small bowel, cecum, and sigmoid). Disruption of this system by local or systemic disease results in symptoms and signs referred to the abdomen. Symptoms include changes in appetite and interest in food, changes in abdominal sensations, including pain, and alterations in stool character and frequency. Physical signs are reflective of changes in overall nutrition, abnormal abdominal contour, evidence of altered intestinal motility or obstruction, solid-organ enlargement, increased peritoneal fluid, and localized mass or tenderness.
Hepatobiliary and Pancreatic System
The hepatobiliary-pancreatic system arises from condensation of mesenchymal tissues around embryonic evaginations of the gut (biliary and pancreatic ducts). The pancreas produces bicarbonate and digestive enzymes (amylase, lipase, and proteinases), which are released in response to ingestion of specific foodstuffs and changes in duodenal contents. It also contains the endocrine islets of Langerhans, which release insulin, glucagon, and somatostatin in response to changes in the blood glucose level and a variety of other stimuli. The liver receives venous blood from the gut, pancreas, and spleen via the portal vein, and percolates it from the portal triads through a radial array of sinusoids to the central vein. From the central vein, blood passes to the heart via the hepatic vein and inferior vena cava (IVC). Hepatocytes perform three general functions: (1) they remove toxic molecules derived from the intestinal contents and systemic metabolism, process them, and release them back into the circulation or secrete them with the bile; (2) they synthesize many of the molecules necessary for maintenance of systemic homeostasis including albumin, coagulation factors, lipoproteins, and transport molecules; and (3) they synthesize and secrete the bile salts that are necessary for digestion and absorption of fats. Kupffer cells are found within the sinusoids. They are phagocytic antigen-presenting cells that clear bacteria from the portal circulation and release cytokines, which enter the systemic circulation. Symptoms related to the hepatobiliary-pancreatic system are changes in general and specific food interest, pain or discomfort associated with the ingestion of food, and maldigestion with changes in bowel function, stool consistency, and frequency. Physical signs relate to (1) changes in the size, consistency, and shape of the liver; (2) to localized pain and masses; and (3) to local and systemic changes caused by alterations in hepatobiliary-pancreatic ...