Sinusitis is characterized by the inflammation of which structures?

Sinusitis is specifically characterized by the inflammation of the sinuses, which are the air-filled cavities located within the bones of the face and skull. When these sinuses become inflamed, it is usually due to an infection, allergic reaction, or other factors that contribute to swelling and blockage of the sinus drainage pathways. This inflammation can lead to symptoms such as nasal congestion, facial pain, headache, and increased mucus production.

While other options refer to different bodily structures, they do not pertain to the condition of sinusitis. Glands are involved in producing hormones and other substances, muscles are responsible for movement, and nerves are related to the transmission of signals within the body. Therefore, recognizing that sinusitis directly involves the sinuses clarifies why this is the correct answer.