What instrument is used to examine the external ear and eardrum?

The instrument used to examine the external ear and eardrum is the otoscope. This specialized tool is designed with a light source and a magnifying lens to provide a clear view of the ear canal and the tympanic membrane (eardrum). By utilizing the otoscope, a healthcare provider can assess for various conditions such as infection, blockages, or abnormalities in the ear structure, allowing for an accurate diagnosis and effective treatment.

The other instruments listed have different purposes: a stethoscope is used to listen to heart and lung sounds, a thermometer measures body temperature, and a sphygmomanometer is used to measure blood pressure. Each of these instruments serves a unique function in medical examinations, but for examining the ear, the otoscope is the specific tool necessary.