1. Drains CSF from the fourth ventricle into the cisterna magna. The two other openings of the fourth ventricle are lateral apertures (foramina of Luschka), one on the left and one on the right, which drain cerebrospinal fluid into the cerebellopontine angle cistern. The median foramen on axial images is posterior to the pons and anterior to the caudal cerebellum. It is surrounded by the obex and gracile tubercles of the medulla, tela choroidea of the fourth ventricle and its choroid plexus, which is attached to the cerebellar vermis. (wikipedia.org)
2. A passage through the midline of the roof of the fourth ventricle of the brain that gives passage to the cerebrospinal fluid from the ventricles to the subarachnoid space. (merriam-webster.com)
3. One of the foramina in the ventricular system and links the fourth ventricle and the quadrigeminal cistern. It is one of the three ways that CSF can leave the fourth ventricle and enter the subarachnoid space. (radiopaedia.org)
4. An opening from the fourth ventricle in the brain to the central canal of the upper end of the spinal cord. (medterms.com)
Syn: Medial aperture, median aperture
Word origin: From Latin foramen “hole, opening, aperture, orifice,” from forare “to pierce.”