A part of the abdominal examination. Hyperextend your nondominant middle finger and place the distal interphalangeal joint over the abdomen. Strike the joint with the other middle finger and evaluate the elicited sound over all four quadrants. Normal findings include tympanic sounds over air-filled or bowel-containing quadrants, with muffled sounds over solid organs (e.g., liver, spleen). Can be used to determine the size and location of intraabdominal organs.