| Hyrtl's foramen | An occasional foramen in the sphenoid bone through which passes the motor portion of the trigeminal nerve; it is formed by ossification of a ligament below and lateral to the foramen ovale. Synonym: Hyrtl's foramen. (05 Mar 2000) |
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| Hyrtl, Joseph | <person> Austrian anatomist, 1810-1894. See: Hyrtl's anastomosis, Hyrtl's foramen, Hyrtl's loop, Hyrtl's epitympanic recess, Hyrtl's sphincter. (05 Mar 2000) |
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| Hyrtl's anastomosis | A communicating loop between the right and left hypoglossal nerves, lying between the geniohyoid and genioglossus muscles or in the substance of the geniohyoid; it is found in about one in ten persons. Synonym: Hyrtl's anastomosis. (05 Mar 2000) |
| Hyrtl's epitympanic recess | The upper portion of the tympanic cavity above the tympanic membrane; it contains the head of the malleus and the body of the incus. Synonym: recessus epitympanicus, attic, epitympanic space, epitympanum, Hyrtl's epitympanic recess, tympanic attic. (05 Mar 2000) |
| Hyrtl's loop | A communicating loop between the right and left hypoglossal nerves, lying between the geniohyoid and genioglossus muscles or in the substance of the geniohyoid; it is found in about one in ten persons. Synonym: Hyrtl's anastomosis. (05 Mar 2000) |
| Hyrtl's sphincter | A band, generally incomplete, of circular muscular fibres in the rectum about 10 cm above the anus (upper rectal ampulla). See: Nelaton's sphincter. (05 Mar 2000) |
| anterior condyloid foramen | The canal through which the hypoglossal nerve emerges from the skull. Synonym: canalis hypoglossalis, anterior condyloid canal of occipital bone, anterior condyloid foramen. (05 Mar 2000) |
| anterior palatine foramen | An opening in the posterolateral corner of the hard palate opposite the last molar tooth, marking the lower end of the pterygopalatine canal. Synonym: foramen palatinum majus, anterior palatine foramen. (05 Mar 2000) |
| aortic foramen | The opening in the diaphragm bounded by the two crura, the vertebral column, and the median arcuate ligament, through which pass the aorta and thoracic duct. Synonym: hiatus aorticus, aortic foramen, aortic opening. (05 Mar 2000) |
| apical dental foramen | The opening at the apex of the root of a tooth that gives passage to the nerve and blood vessels. Synonym: foramen apicis dentis, apical dental foramen, root foramen. (05 Mar 2000) |
| apical foramen of tooth | The opening at the apex of the root of a tooth that gives passage to the nerve and blood vessels. Synonym: foramen apicis dentis, apical dental foramen, root foramen. (05 Mar 2000) |
| arachnoid foramen | The large midline opening in the posterior inferior part of the roof of the fourth ventricle, connecting the ventricle with the cerebellomedullary cistern. Synonym: apertura mediana ventriculi quarti, arachnoid foramen, Magendie's foramen, median aperture of the fourth ventricle. (05 Mar 2000) |
| Bichat's foramen | <anatomy, vein> An expansion of the subarachnoid space extending forward between the corpus callosum and the thalamus; it encloses the internal cerebral veins which caudally join to form the vena magna cerebri (Galen's vein). Synonym: ambient cistern, Bichat's canal, Bichat's foramen, cistern of great vein of cerebrum, cisterna ambiens, cisterna superioris, cisterna venae magnae cerebri, superior cistern. (05 Mar 2000) |
| blind foramen of frontal bone | <anatomy> Blind or caecal foramen of the frontal bone; the blind foramen formed immediately anterior to the crista galli by a notch at the lower end of the frontal crest and its articulation with the ethmoid bone. It is insignificant postnatally, but gives passage to vessels during development. Synonym: foramen caecum ossis frontalis, blind foramen of frontal bone, caecal foramen of frontal bone. (05 Mar 2000) |
| blind foramen of the tongue | <anatomy> A median pit on the dorsum of the posterior part of the tongue, from which the limbs of a V-shaped furrow run forward and outward; it is the site of origin of the thyroid gland and subsequent thyroglossal duct in the embryo. Synonym: foramen caecum linguae, blind foramen of the tongue, caecal foramen of the tongue, Morgagni's foramen, pleuroperitoneal foramen. (05 Mar 2000) |
| Bochdalek's foramen | An opening through the diaphragm, connecting pleural and peritoneal cavities, usually the result of defective development of the pleuroperitoneal membrane in the embryo; if the defect is extensive there may be herniation of digestive organs into the pleural cavity. See: diaphragmatic hernia. Synonym: Bochdalek's foramen. (05 Mar 2000) |