Foramen

The word [foramen] is a Latin word meaning "opening, aperture, hole", from the Latin term [forare] meaning to bore a hole, to pierce. The plural form of the word is [foramina]. There are many foramina in the human body.

• Epiploic foramen (of Winslow): An opening bound by the lesser omentum, the inferior vena cava, duodenum and liver. It is a communication between the main peritoneal cavity and lesser sac, an area found posterior to the stomach.
• Nutritional foramina: Openings found in most bones allowing for passage of blood vessels.
• Obturator foramen: An opening in the pelvis bound by the following bones: ilium, ischium, and os pubis. Indicated in the accompanying image by an arrow. 
• Foramen of Monro: A communication between the lateral ventricle and the third ventricle of the brain. There are actually two foramina of Monro (one on each side), and are important for cerebrospinal fluid circulation. Named after Alexander Monro Secundus (1733 - 1817).

 
Obturator Foramen