| incisura ethmoidalis | An oblong gap between the orbital parts of the frontal bone in which the ethmoid bone is lodged. Synonym: incisura ethmoidalis. (05 Mar 2000) |
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| labyrinthus ethmoidalis | A mass of air cells with thin bony walls forming part of the lateral wall of the nasal cavity; the cells are arranged in three groups, anterior, middle, and posterior, and are closed laterally by the orbital plate which forms part of the wall of the orbit. Synonym: labyrinthus ethmoidalis, ectethmoid, ectoethmoid, lateral mass of ethmoid bone. (05 Mar 2000) |
| lamina cribrosa ossis ethmoidalis | A horizontal lamina from which are suspended the labyrinth, on either side, and the lamina perpendicularis in the centre; it fits into the ethmoidal notch of the frontal bone and supports the olfactory lobes of the cerebrum, being pierced with numerous openings for the passage of the olfactory nerves. Synonym: lamina cribrosa ossis ethmoidalis, cribrum, sieve bone, sieve plate. (05 Mar 2000) |
| lamina orbitalis ossis ethmoidalis | A thin plate of ethmoid bone forming part of the medial wall of the orbit and the lateral wall for the ethmoidal labyrinth. Synonym: lamina orbitalis ossis ethmoidalis, lamina papyracea, orbital lamina of ethmoid bone, orbital layer of ethmoid bone, orbital plate, paper plate, papyraceous plate. (05 Mar 2000) |
| lamina perpendicularis ossis ethmoidalis | A thin plate of bone projecting downward from the crista galli of the ethmoid; it forms part of the nasal septum. Synonym: lamina perpendicularis ossis ethmoidalis. (05 Mar 2000) |
| fovea ethmoidalis | The roof of the ethmoid air cells. (05 Mar 2000) |
| adductor hiatus | The aperture in the aponeurotic insertion of the adductor magnus that transmits the femoral artery and vein from the adductor canal to the popliteal space. Synonym: hiatus tendineus, hiatus adductorius, femoral opening, tendinous opening. (05 Mar 2000) |
| aortic hiatus | 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) |
| Breschet's hiatus | <anatomy> The opening by which the two scalae communicate at the top of the cochlea of the ear. Origin: NL, fr. Gr, a helix + a hole. Source: Websters Dictionary (01 Mar 1998) |
| maxillary hiatus | The large opening into the maxillary sinus on the nasal surface of the maxilla. Synonym: hiatus maxillaris. (05 Mar 2000) |
| pleuropericardial hiatus | An opening connecting the pleural and pericardial cavities; usually the result of incomplete development of the pleuropericardial fold of the embryo. (05 Mar 2000) |
| pleuroperitoneal hiatus | 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) |
| cornu inferius marginalis falciformis hiatus sapheni | The lower part of the falciform margin of the opening in the fascia lata through which the greater saphenous vein passes. Synonym: cornu inferius marginalis falciformis hiatus sapheni. (05 Mar 2000) |
| sacral hiatus | A normally-occurring gap at the lower end of the sacrum, exposing the vertebral canal, due to failure of the laminae of the last sacral segment to coalesce. It is closed by the sacrococcygeal ligament, and provides cannular access to the sacral epidural space for administration of anaesthetics (caudal nerve blocks). Synonym: hiatus sacralis. (05 Mar 2000) |
| saphenous hiatus | The opening in the fascia lata inferior to the medial part of the inguinal ligament through which the saphenous vein passes to enter the femoral vein. Synonym: hiatus saphenus, fossa ovalis, saphenous hiatus. (05 Mar 2000) |