Abdominal rigidity is a state of involuntary contraction in the muscles of the abdominal wall resulting from a stimulation of either the spinal cord or the basal ganglia that is not transmitted to the visceral nerves. Involuntary guarding of the abdominal musculature, and rebound tenderness (pain when pressure is released) may accompany this state. A patient exhibiting both rebound tenderness and abdominal rigidity is an urgent surgical condition that requires immediate transport to a surgical receiving facility.
During this process, the physician should ask questions concerning the nature of the pains - are they dull or sharp, do they recur or travel to other parts of the body? When did they start and how long have they lasted? The physician should also determine whether the pains are constant or come and go, and if they are worse or better after eating.
The doctor should perform a thorough physical examination of the abdomen. This examination should include a pelvic and rectal exam. During the exam, the physician should inspect for masses. He should also recheck for the presence of fluid in the membrane surrounding the abdomen (the peritoneum), and note its location, size, and tenderness. He should check for movement of the mass with respiration and for a pulsating sensation, which can indicate a dilated bowel.
If a mass is found, the physician should attempt to differentiate the mass from a hernia of the abdominal wall. The physician can do this by asking the patient to raise his head off the examining table or his feet off the table. This will tense the abdominal wall muscles and make an intra-abdominal mass more prominent.