What binds the tympanic membrane to the temporal bone?

The structure that binds the tympanic membrane to the temporal bone is the annular ligament. This ligament acts as a supportive ring that holds the tympanic membrane in place at its periphery, ensuring that the membrane is securely connected to the bony structure of the temporal bone. This connection is essential for the functioning of the tympanic membrane, as it vibrates in response to sound waves, ultimately contributing to the process of hearing.

The other choices relate to different components of the ear or structures that do not provide this specific connection. The tensor tympani muscle, for instance, is involved in dampening the vibrations of the tympanic membrane to protect the inner ear from loud sounds, but it does not provide a binding connection to the temporal bone. The cochlear duct is part of the inner ear and plays a role in the auditory pathway but doesn't bind the tympanic membrane. The eustachian tube is responsible for equalizing pressure between the middle ear and the atmosphere, again not involving the binding of the tympanic membrane to the bone. Each of these structures has its own important function, but only the annular ligament serves this specific purpose regarding the tympanic membrane's attachment to the temporal bone.