Examination of the abdomen begins with inspection. The shape of the abdomen in most normal persons with normal musculature is boat-shaped i.e. the abdominal wall sinks slightly within the bony margins of the abdominal surface.
In a very muscular person, the lateral margin of the rectus muscle is visible in the center. Usually the medial edges of both the recti are contiguous. However they may be separated as a congenital defect, after pregnancy or with obesity and ascites. This is called divarication of recti.
Scaphoid or sunken abdomen is seen with starvation and malignancy especially of stomach and esophagus.
Normal umbilicus is usually inverted and situated centrally in the mid-abdomen. The distance between the xiphisternum and the umbilicus is equal to the distance between the umbilicus and symphysis pubis.
In ascites, the distance between xiphisternum and umbilicus is greater than that between umbilicus and symphysis pubis, whereas in ovarian tumour the distance between xiphisternum and umbilicus is less than that between umbilicus and symphysis pubis.
In ascites, te umbilicus is transversely stretched (smiling) or flattened or everted whereas in obesity, the umbilical cleft is deeper than norma.
Everted umbilicus may occur with herniation of bowel or fat into the widened umbilical ring. Sometimes, umbilicus may exude fluid e.g. ascetic fluid in massive ascites or feculent material in enteric fistulae, or clear fluid in patent urachus (crying umbilicus).
Bluish discoloration or periumbilical region (Cullen sign) occurs in acute haemorrhagic pancreatitis or ruptured ectopic pregnancy.
Cherry-red swelling of the umbilicus suggests inflamed Meckel’s diverticulum.
Normally the abdominal wall bulges during inspiration and falls during expiration. In diaphragmatic paralysis the abdomen bulges during expiration. In peritonitis, the abdominal movements are absent.
Normally pulsations are not visible over the abdomen. They may be visible in the following conditions:
- Aortic pulsations are visible in the nervous, anaemic individual.
- Aortic aneurysm produces expansile pulsations in any position.
- Transmitted pulsations from a tumour overlying the aorta disappear in knee-elbow position because the tumour falls away from the aorta in that position. This is not so if the tumour is adherent to the aorta.
- Right ventricular pulsations are seen only in the epigastrium and correspond with the apex beat.
- Congested liver, in addition, produces pulsations posteriorly.
Suggest venous obstruction. When dilated veins are present, the direction of the blood flow can be found by emptying (milking) a section of the vein and pressing each end of the emptied part with a finger. One finger is released and the filling of the vein is noted. Similarly, the other finger is released and filling of the vein is noted. Blood enters more rapidly and fills the veins from the direction of the blood flow.
Inferior vena cava obstruction
There will be dilated veins on the sides with flow of blood from below upwards. This occurs because the blood bypasses the inferior vena cava and travels from the lower limbs to the thorax via the veins of the abdominal wall. These veins are anastomotic channels between the superficial epigastric vein and circumflexiliac veins below and the lateral thoracic vein above conveying the diverted blood from the long saphenous vein to the axillary vein.
Portal vein obstruction
The engorged veins are centrally placed and may form a cluster around the umbilicus (caput medusa). The blood in these veins flows in all directions away from the umbilicus. They represent opening of anastomosis between portal and systemic veins.
Peristalsis is best elicited by patiently observing the abdomen of the patient for some time. If it is not visible, an attempt to visualize it should be made either by making the patient swallow fluids or by applying sharp tap with the finger over the abdominal wall.
Peristaltic wave of the stomach is seen in pyloric stenosis in the epigastrium and left hypochondriac region, moving from left to right. Peristaltic wave of the large intestine (transverse colon) is seen in the same region but moving from right to left. Peristaltic wave of small intestine is seen in a ladder pattern down the centre of the abdomen.
The hernial sites in the groin should be seen for any swelling. If there is no swelling, the patient should be asked to stand up, turn his head to one side and cough. If there is an impulse on coughing it suggests hernia.
Smooth and glossy skin indicates abdominal distension whereas wrinkled skin suggests old distension which has been relieved.
Abdominal striae (stretch marks) represent the rupture of subepidermal connective tissue as a result of recent or past abdominal distension. It is seen commonly following pregnancy, in obesity, in massive ascites and following corticosteroid therapy. When they first form, the striae are reddish or pink. If the state of distension stabilizes or the cause regresses, the colour fades to white.