Percussion is a valuable technique that helps determine whether the viscera present under the percussed area is a solid mass or has some air.
How to perform percussion? What is the technique of percussion?
• Place your middle finger over and parallel to the organ to be percussed. The middle phalanx should be in firm contact with the surface of the body while other fingers must be placed gently over the skin.
• Flex the middle finger of the right hand at the proximal interphalangeal joint and strike the middle phalanx of the left hand at a right angle.
• The movement must be at the wrist joint and not at the elbow joint.
• Strike the phalanx two times.
• Percuss lightly, as heavy percussion can aside discomfort to the patient.
While examining the abdomen, we do

• Inspection of abdomen
• Palpation of abdomen
• Percussion of abdomen
• Auscultation of abdomen
Why do we do percussion of the abdomen?
• To define the boundaries of different organs
• To detect if a patient has ascites

• To differentiate between ascites and ovarian cysts
Which organs do we percuss while examining the abdomen?
• Liver
• Lower border of the Spleen

• Enlarged urinary bladder
• Ascites
• Ovarian cyst
Percussion of liver
The liver is percussed to determine the location of its upper and lower border. The liver span is then measured to see if the liver is enlarged or not. The average liver span is 12-15cm. It will be increased if the liver is enlarged.
The method of percussion is the same as discussed above. Keep the following points in mind while percussing the liver.
• Start from the second right intercostal space in the midclavicular line.
• Move downward and percuss the second and third intercostal spaces, and so on. The note heard is resonant due to the presence of the right lung. Note when the note becomes impaired instead of resonant.
• The impaired note denotes the presence of the upper border of the liver.

• Plapate the lower border of the liver, or you can percuss it, starting from the right iliac fossa towards the right costal margin.
• Measure the distance between the upper and lower border using tape in the midclavicular line. This is called the liver span.
Percussion of the lower border of the spleen
The upper border of the spleen is usually under the left costal margin. The lower border can be percussed.

Start percussing from the right iliac fossa placing your finger parallel to the left costal margin.
The point at which the note becomes dull instead of resonant is the lower border of the spleen.
Percussion of the enlarged urinary bladder
The urinary bladder is percussed from the epigastrium towards the hypogastrium. The note becomes dull only if the urinary bladder is enlarged.
Ascites refer to abnormal free fluid accumulation in the abdomen(peritoneum). It can be detected by percussing the abdomen.
On percussion, you can feel two signs
• Shifting dullness
• Fluid thrill
Shifting dullness
It refers to the shifting of dull sound from one part of the abdomen to the other.
First, the abdomen is percussed from the epigastrium up to the umbilicus and then laterally. Usually, the note is resonant up to the extreme of flanks, where it becomes dull. Note the dull point and ask the patient to turn to opposite side. Wait a few seconds to allow the possible fluid to move to the other side.
Now percuss the dull point. If it has become resonant, percuss towards the umbilicus, shifting dullness is said to be present if the previously resonant area towards the umbilicus has become dull.
It marks the presence of ascites.
Fluid thrill
To elicit a fluid thrill, place your hand over the left lumber region. Tap on the opposite side and feel a thrill from the hand placed over the lumber region. In the case of obese persons, ask the attendant or the patient to place their hand firmly in the midline to prevent pulse transmission through the fat in the abdominal wall.
Ovarian cyst
In the case of ovarian cysts in women, the note felt on percussion will b dull in the midline while resonant in the flanks due to lateral pushing of the intestinal loops. It is opposite to the ascites, where the note is resonant in the midline and dull in the flanks. Moreover, the swelling starts from the lower part of the abdomen in the ovarian cyst while from the flanks in the case of ascites.
These organs can be purchased, and we can pick different findings while examining the abdomen.