When taking a client's temperature with an aural thermometer, where should it be placed?

When using an aural thermometer, it is specifically designed to measure temperature via the ear canal. The ear is an optimal site for measuring body temperature because it is close to the body's core and can provide a fairly accurate reading. The tympanic membrane (eardrum) reflects the body’s internal temperature, making this method both reliable and quick.

In contrast, the other options do not pertain to the proper use of an aural thermometer: measuring temperature in the mouth uses an oral thermometer, the armpit is used with an axillary thermometer, and the nose is not a conventional site for temperature measurement with any standard thermometers. This highlights why placing the thermometer in the ear is the correct choice. The design of an aural thermometer ensures that it can properly accommodate the auditory canal structure, making it essential to use it as intended for accurate results.