How should a rectal thermometer be inserted in adults?

The correct method for inserting a rectal thermometer in adults involves specific guidelines to ensure accurate readings and patient safety. When inserting a rectal thermometer, it should be lubricated to minimize discomfort and facilitate smooth insertion. The thermometer is directed towards the umbilicus (belly button) because this orientation aligns with the natural curvature of the rectum and ensures that the thermometer is positioned appropriately in the rectal cavity for accurate temperature measurement.

Inserting the thermometer towards the umbilicus also helps reduce the risk of damaging the rectal lining and ensures the thermometer reaches the appropriate area for reading core body temperature. Proper insertion depth is generally around 1 inch to 1.5 inches in adults, depending on the specific thermometer and patient size, but option B correctly states to direct it towards the umbilicus while maintaining the appropriate depth to achieve an accurate reading.