Procedure
- Carefully lay the dominant (palpating) hand on the abdomen with fingers together [Figure 20]; the wrist of this hand held straight. The patient can breathe normally
- Feel for any subcutaneous masses
- Determine abdominal muscle tone by pressing lightly on the abdominal wall using the volar side of the fingertips of the second through fifth fingers
- If necessary, to avoid abdominal wall contraction, have the patient bend the knees or place a pillow under the knees
Figure 20
Points to consider
- Describe the degree of abdominal muscle tension qualitatively: normal (soft abdomen), moderately rigid, very rigid, or completely rigid.
- For cases of increased abdominal muscle tone, distinguish between active and passive (involuntary) muscle guarding. Involuntary guarding is an important symptom.
Active muscle guarding can be overcome by distracting the patient (e.g. have the patient breathe deeply, talk to the patient, apply light pressure on abdominal muscles for a longer period while talking to the patient); passive guarding will remain unchanged - Determine whether the increased muscle tension is localised or diffuse
- Determine whether light palpation is painful. Determine the perimeters of the painful region using palpation
- Determine whether any masses can be felt through the abdominal wall.
Sometimes it is unclear whether the mass (or cause of palpation tenderness) lies in the abdominal wall or abdominal cavity. Differentiation is possible as follows:
– have the patient tense the abdominal muscles by raising both outstretched legs slightly from the table;
– palpate again;
– if the mass remains palpable and moveable, it is located in the subcutaneous tissue; if the mass remains palpable but fixed, it is located in the abdominal muscle; if the mass is no longer palpable, it is located in the abdominal cavity;
– if the pain upon palpation persists, the cause is located in the abdominal wall; if not, then it is found in the abdominal cavity.