Definition of fornix in US English:



  • 1A vaulted or arched structure in the body.

    • ‘This again removes debris that could have hung up at the edge of the keratectomy and not run to the fornices.’
    • ‘The lateral fornices may be lavaged without manipulation by directing the stream into them.’
    • ‘Excessively large implants may also compromise the fornices and possibly limit motility.’
    • ‘The fornices should be palpated around the cervix for nodules suggestive of endometriosis, and may also be the etiology for fixed adnexa or may result from pelvic inflammatory disease.’
    • ‘The anterior part of the septum and the third ventricular roof were deficient with a narrow Monro's foramen and the third ventricular floor was visible through the space between both fornices.’
    1. 1.1 A triangular area of white matter in the mammalian brain between the hippocampus and the hypothalamus.
      • ‘The fornix, mamillary bodies, and part of the anterior commissure can also be seen.’
      • ‘The fornix is an arching, fibrous band of nerve fibers.’
      • ‘Between the two crura of the fornix is a white, triangular lamina, known as the fornical commissure.’
      • ‘The septum pellucidum stretches across the interval between the genu of the corpus collosum and the columns of the fornix, separating the frontal horns of the two lateral ventricles.’
      • ‘Axons of neurons in the hippocampus (a specialized part of the cerebral cortex involved in conscious memory) run in a tract called the fornix, which ends on neurons in the mammillary bodies of the hypothalamus.’


Late 17th century: from Latin, literally ‘arch, vaulted chamber’.