Also called tympanic antrum, the mastoid antrum is located in the the temporal bone. It is part of the middle ear, and is localized after the tympanic membrane. The size of this cavity varies from person to person, and it can be proportional to body size. Small air cells surround the mastoid antrum, which is frequently a site for ear infections that are difficult to eradicate.
The pyloric antrum is an area of the stomach near the pyloric valve, which controls the exit of food to the intestines. The pyloric antrum mucosa, which is the membrane that covers this cavity, has an irregular pattern of ridges, slits and furrows. The membrane also contains structures called pyloric foveolae, which are responsible for the production of mucus, a secretion that protects the stomach cells.
The follicular antrum is part of the ovarian follicule, which in a sexually mature woman is developed and liberated from the ovary only once a month. The small cavity of the follicular antrum contains a liquid called follicular fluid, which is rich in hyaluronic acid. The egg cell, or oocyte, is found in the follicular antrum, surrounded by the follicular fluid. In the case of fertilization and pregnancy, the follicular antrum eventually become part of the placenta.
Located in the human face, just below the prominence of the cheek, the maxillary antrum is also called maxillary sinus or Antrum of Highmore. It is an air-filled cavity of pyramidal shape, which communicates with the nose. It is the largest of the paranasal sinuses. Mucus protects the maxillary antrum and the other sinuses against bacteria and infection. However, too much mucus can block the air passage in the maxillary antrum, causing the growth of bacteria and the infection sinusitis.