| ethmoidal foramen | Either of two foramina formed by grooves on either edge of the ethmoidal notch of the frontal bone, and completed by similar grooves on the ethmoid bone: anterior ethmoidal foramen, located in an anterior position; posterior ethmoidal foramen located in a posterior position. Synonym: foramen ethmoidale. (05 Mar 2000) |
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| ethmoidal groove | A groove on the inner surface of each nasal bone, lodging the external nasal branch of the anterior ethmoid nerve. Synonym: sulcus ethmoidalis. (05 Mar 2000) |
| ethmoidal infundibulum | A passage from the middle meatus of the nose communicating with the anterior ethmoidal cells and frontal sinus. Synonym: infundibulum ethmoidale, ethmoid infundibulum. (05 Mar 2000) |
| ethmoidal labyrinth | 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) |
| ethmoidal-lacrimal fistula | A fistulous communication between the lacrimal sac and the ethmoidal sinus. Synonym: internal lacrimal fistula. (05 Mar 2000) |
| ethmoidal notch | An oblong gap between the orbital parts of the frontal bone in which the ethmoid bone is lodged. Synonym: incisura ethmoidalis. (05 Mar 2000) |
| ethmoidal veins | Veins that accompany the anterior and posterior ethmoidal arteries and pass into the superior ophthalmic vein; they drain the ethmoidal sinuses. Synonym: venae ethmoidales. (05 Mar 2000) |
| lateral nasal branches of anterior ethmoidal nerve | <anatomy, nerve> Branches of nasociliary nerve distributed to walls of nasal cavity. Synonym: rami nasales laterales nervi ethmoidalis anterioris. (05 Mar 2000) |
| ABC process | Purification of water or deodorization of sewage by a mixture of alum, blood, and charcoal. (05 Mar 2000) |
| accessory process | A small apophysis at the posterior part of the base of the transverse process of each of the lumbar vertebrae. Synonym: processus accessorius, accessory tubercle. (05 Mar 2000) |
| acromial process | <anatomy> The lateral triangular projection of the spine of the scapula that forms the point of the shoulder and articulates with the clavicle. (27 Sep 1997) |
| activated sludge process | <procedure> A method of treating sewage and wastewater through microbial oxidation. Sewage previously treated in settling tanks is aerated to encourage the growth of nonpathogenic aerobic microorganisms (bacteria, yeasts, moulds and protozoans) which break the organic matter down into carbon dioxide, water and simple salts. After this activated sludge is produced, the wastewater undergoes further processing through anaerobic digestion, filtering and chlorination. (29 Dec 1997) |
| adiabatic process | <chemistry> A process in which the system does not exchange heat with the surroundings. (15 Jan 1998) |
| agene process | Bleaching of flour with nitrogen trichloride (prohibited in the United States). (05 Mar 2000) |
| alar process | A small lateral expansion of the ethmoid bone from the front of the crista galli on each side that articulates with the frontal bone and forms the foramen caecum. Synonym: ala cristae galli, alar process. (05 Mar 2000) |