Tympanic bulla

Tympanic Bulla

The tympanic bulla is a hollow bony structure that forms part of the middle ear in mammals. It is responsible for housing and protecting the delicate structures of the middle ear, including the auditory ossicles and the Eustachian tube. The tympanic bulla is particularly prominent in certain species, such as cetaceans and carnivores, where it is often used in taxonomic identification.

Structure and Function

The tympanic bulla is typically a rounded or oval structure, located at the base of the skull. It is formed by the tympanic part of the temporal bone, and is separated from the rest of the skull by a thin layer of connective tissue. The interior of the bulla is filled with air, which allows for the transmission of sound waves from the ear drum to the inner ear.

The primary function of the tympanic bulla is to protect the structures of the middle ear. It also plays a role in the amplification of sound, as the air-filled space within the bulla can resonate with incoming sound waves, increasing their intensity before they reach the inner ear.

Clinical Significance

In veterinary medicine, diseases of the tympanic bulla are relatively common, particularly in cats and dogs. These can include otitis media, or inflammation of the middle ear, and neoplasia, or abnormal growth of tissue. Treatment for these conditions often involves surgery to open the bulla and remove the diseased tissue.

In humans, the tympanic bulla is less prominent, but can still be affected by disease. Conditions such as cholesteatoma, a benign growth of skin cells in the middle ear, can cause damage to the bulla and other structures of the ear.

See Also

• Middle ear
• Auditory ossicles
• Eustachian tube
• Otitis media
• Cholesteatoma