Which test measures the physical volume of air in the ear canal?

The test that measures the physical volume of air in the ear canal is known as tympanometry. This test evaluates the mobility of the eardrum by creating variations in air pressure in the ear canal. During tympanometry, a probe is inserted into the ear, and it measures how well the eardrum moves in response to changes in pressure. This allows the clinician to determine the ear canal volume as well as assess how well the eardrum is functioning, which can be indicative of various conditions affecting the middle ear.

Static acoustic impedance assesses the physical characteristics of the ear and can provide information about the ear's conductive function, but it does not specifically measure the volume of air in the ear canal. Pure tone audiometry is used to assess hearing sensitivity across different frequencies and does not involve measuring ear canal volume. Impedance audiometry is a general term that includes tests like tympanometry, but it is not specific to measuring ear canal volume directly. Thus, tympanometry is the precise test used for this purpose.