Cat owners are almost as curious as the cats they own. Cat anatomy is fairly straightforward, but have you ever noticed, when petting your cat, those odd little pockets on the side of your cat's ears? What are these strange pockets for? It's a question we hear frequently from cat owners so we figured we'd take the opportunity to shed some light on this odd part of your cat's ear anatomy.
But first, a brief anatomy overview. Cats have been around for a long time and have evolved into well-adapted animals for their environments. Like human ears, the cat's ear is an organ for hearing and balance. It consists of an outer, middle and inner ear (see the graphic below right).
The inner ear is a complex structure that includes the cochlea (the organ of hearing) and the vestibular system (the organ of balance). The semicircular canals, which are found within the inner ear, are filled with fluid and are important for maintaining balance. These are highly developed in the cat, accounting for its agility and excellent sense of balance.
The middle ear includes the eardrum and a small, air-filled chamber that contains 3 tiny bones: the hammer, anvil, and stirrup. It also includes 2 muscles, the oval window, and the eustachian tube (a small tube that connects the middle ear with the back of the nose, allowing air to enter the middle ear).
The outer ear includes the pinna (the part you see that is made of cartilage and covered by skin, fur, or hair) and the ear canal. The pinna is shaped to capture sound waves and funnel them through the ear canal to the eardrum. In cats, the pinnae are mobile and can move independently of each other. The ear canal of cats is deeper and more tapered than in humans, creating a better funnel to carry sound to the eardrum. This deeper canal is subject to buildup of dirt and wax that can lead to inflammation and secondary infection, although to a lesser degree than in dogs.
information quoted from merckvetmanual.com
The little pocket in your cat's ear we referred to at the beginning of this post is called the cutaneous marginal pouch or Henry's pocket or pouch. [My own curious mind wondered, "Why Henry's pocket?" but after much online searching I couldn't find the answer and it will have to remain a mystery.] Interestingly enough, no one really knows what this pocket is for but it is speculated that it enhances your cat's hearing, possibly of higher frequency sound. The cutaneous marginal pouch isn't just found in cats— it can be seen on various animals, including dogs.
As we know, parasites love to gather in dark, recessed areas and the pouch fits the bill. During an exam your veterinarian may check your cat's ear and pay special attention to Henry's pocket to make sure it's clear. Regular and proper ear care for you cat is important! Clean your cat's ear at least once a week. For more information on how to do this, follow this link.