Final answer:
Tenderness is not a peritoneal sign; peritoneal signs include guarding, rebound, and rigidity, which suggest irritation of the peritoneum, whereas tenderness can be due to different conditions.
Step-by-step explanation:
In the context of abdominal assessment, the finding that is NOT a peritoneal sign is tenderness.
Peritoneal signs are specific clinical indicators that suggest irritation of the peritoneum, the membrane lining the abdominal cavity. These signs include guarding, which is a voluntary or involuntary tensing of the abdominal muscles when pressed, rebound, which refers to increased pain upon sudden release of pressure on the abdomen, and rigidity, which signifies involuntary muscle spasm of the abdominal wall, indicative of severe inflammation underneath. While abdominal tenderness indicates discomfort upon application of pressure, it is not specific to peritoneal irritation and can be caused by a variety of conditions.