👉 Sinuses are openings or cavities in the inner ear that contain a small amount of fluid, called mucus. They help to filter out sound waves from the outer ear and allow for better hearing. In humans, there are two types of sinuses: 1. The frontal sinus (also known as the mastoid sinuses) are located above the ears and provide protection against external sounds. 2. The maxillary sinus (also known as the submandibular sinuses) is located below