In biology, antrum is a general term for a cavity or chamber, which may have specific meaning in reference to certain organs or sites in the body.
In vertebrates, it may refer specifically to:
- Antrum follicularum, the cavity in the epithelium that envelops the oocyte
- Mastoid antrum, a cavity between the middle ear and temporal bone in the skull
- Stomach antrum, either[1]
- Pyloric antrum, the initial portion of the pyloric part of the stomach. This is what is usually referred to as "antrum" in stomach-related topics,[citation needed]
- or Antrum cardiacum, a dilation that occurs in the esophagus near the stomach (forestomach)
- Maxillary antrum or antrum of Highmore, the maxillary sinus, a cavity in the maxilla and the largest of the paranasal sinuses
In invertebrates, it may refer specifically to:
- Antrum of female lepidoptera genitalia
- ^ "What Is an Antrum?". healthline.com.
There are two different antra that exist in or near the stomach