Auscultation of Abdomen
The patient is positioned comfortably in the supine position.
The stethoscope is used to listen over several areas of the abdomen for several minutes for the presence of bowel sounds. The diaphragm of the stethoscope should be applied to the abdominal wall with firm but gentle pressure.
It is often helpful to warm the diaphragm in the examiner’s hands before application, particularly in ticklish patients. When bowel sounds are not present, one should listen for a full 3 minutes before determining that bowel sounds are, in fact, absent.
Auscultation for abdominal bruits is the next phase of abdominal examination. Bruits are “swishing” sounds heard over major arteries during systole or, less commonly, systole and diastole. The area over the aorta, both renal arteries. and the iliac arteries should be examined carefully for bruits.
Rubs are infrequently found on abdominal examination but can occur over the liver, spleen, or an abdominal mass.
Clinical Significance
Peristalsis
These are intestinal sounds generated by contractions of the muscular walls of the gut and resultant vibration of the gut wall produced by movement of a gas-fluid mixture through the gut. These bowel sounds (peristalsis) persist in the fasting state due to the presence of intestinal secretions and swallowed air.
Loud bowel sounds (hyperperistalsis) accompanied by abdominal distension and crampy abdominal pain suggests partial bowel obstruction.
Arterial Bruit
These may occur by unusually acute angulations at arterial branch points arteriosclerotic plaques, extreme tortuousity of an artery, or massive blood flow through very vascular tumours like hemangiomas or hepatoma.
Bruits over the liver suggests very vascular tumour like hepatoma or angioma, Similarly, over the spleen it suggests hemangioma or vascular tumour. Bruit over the aorta, if soft, has no significance. A loud bruit suggests aortic aneurysm, atherosclerosis or extreme tortuousity of the aorta.
Bruit over the kidneys in the flanks suggests renal artery stenosis.
Venous Hum
Venous hum is continuous, softer and lower pitched than bruit. It signifies portal systemic shunting of venous flow when portal flow is obstructed. It is usually heard over the liver area and umbilicus.
