A dog's ear is responsible for hearing and balance. It has three parts: the outer ear, the middle ear, and the inner ear.
The outer ear includes the pinna (the flap of cartilage covered by skin and hair) and the ear canal.
The size and shape of the pinna vary by breed. The pinna catches sound and channels it down the ear canal to the eardrum. Dogs can move the left and right pinna independently.
The dog’s ear canal is much longer than a human’s, which makes dogs better at detecting sound and able to hear higher frequencies. On average, dogs hear roughly 4 times better than people.
The middle ear contains the eardrum and a small air-filled chamber with three tiny bones. It also contains two small muscles, an opening called the oval window, and the auditory tube, which links the middle ear to the back of the nose and lets air enter the middle ear.
The inner ear is complex and includes thecochlea(the hearing center) and the system that controls balance.
Physical Examination of the Ear
Ear infections and other ear problems are common in dogs. Veterinarians check a dog’s ears as part of a routine exam.
A vet starts by checking the outer ear for inflammation, injuries, swelling, unusual discharge, or excess wax. A tool called an otoscope is used to look down the ear canal and view the eardrum. Hair sometimes must be removed from the ear canal for a clear view of the eardrum.
If infection is suspected, the vet will sample and test fluid or discharge in the ear to find the organisms involved and pick the right treatment. Ear infections in dogs are most often caused by bacteria or yeast.
Additional tests—x-rays, CT scan, MRI testing, or electronic hearing tests—might be needed to confirm certain conditions, including deafness. Diagnosing a tumor usually requires a biopsy.
