| ala cristae galli | 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) |
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| ala major ossis sphenoidalis | Strong squamous processes extending in a broad superolateral curve from the body of the sphenoid bone. The greater wing presents these suraces (facies): 1) cerebral surface: forms anterior third of the floor of the lateral portions of the middle cranial fossa; 2) temporal surface: forms the deepest portion of the temporal fossa; 3) infratemporal surface, forms the "roof" of the infratemporal fossa; 4) orbital surface: forms posterolateral wall of orbit. The greater wing forms the inferior border of the supraorbital fissure, and is perforated at its root by foramina rotundum ovale, and spinosum and the pterygoid canal. Synonym: ala major ossis sphenoidalis, ala temporalis. (05 Mar 2000) |
| ala minor ossis sphenoidalis | One of a bilateral pair of triangular, pointed plates extending laterally from the anterolateral body of the sphenoid bone. Forming the posteriormost portion of the floor of the anterior cranial fossa, their sharp posterior edge forms the sphenoidal ridge separating anterior and middle cranial fossae. The medial end of the lesser wing attaches to the body by means of two pedicles, thus forming the optic canal. The wing itself forms the superior margin of the supraorbital fissure. Synonym: ala minor ossis sphenoidalis, ala orbitalis, Ingrassia's apophysis, Ingrassia's wing. (05 Mar 2000) |
| ala nasi | The outer more or less flaring wall of each nostril. Synonym: ala nasi, pinna nasi. (05 Mar 2000) |
| ala orbitalis | One of a bilateral pair of triangular, pointed plates extending laterally from the anterolateral body of the sphenoid bone. Forming the posteriormost portion of the floor of the anterior cranial fossa, their sharp posterior edge forms the sphenoidal ridge separating anterior and middle cranial fossae. The medial end of the lesser wing attaches to the body by means of two pedicles, thus forming the optic canal. The wing itself forms the superior margin of the supraorbital fissure. Synonym: ala minor ossis sphenoidalis, ala orbitalis, Ingrassia's apophysis, Ingrassia's wing. (05 Mar 2000) |
| ala ossis ilii | The upper flaring portion of the ilium. Synonym: ala ossis ilii. (05 Mar 2000) |
| ala sacralis | The upper surface of the lateral part of the sacrum adjacent to the body. Synonym: ala sacralis. (05 Mar 2000) |
| ala temporalis | Strong squamous processes extending in a broad superolateral curve from the body of the sphenoid bone. The greater wing presents these suraces (facies): 1) cerebral surface: forms anterior third of the floor of the lateral portions of the middle cranial fossa; 2) temporal surface: forms the deepest portion of the temporal fossa; 3) infratemporal surface, forms the "roof" of the infratemporal fossa; 4) orbital surface: forms posterolateral wall of orbit. The greater wing forms the inferior border of the supraorbital fissure, and is perforated at its root by foramina rotundum ovale, and spinosum and the pterygoid canal. Synonym: ala major ossis sphenoidalis, ala temporalis. (05 Mar 2000) |
| ala vespertilionis | An obsolete term for broad ligament of the uterus. Origin: L. Bat's wing (05 Mar 2000) |
| ala vomeris | An everted lip on either side of the upper border of the vomer, between which fits the rostrum of the sphenoid bone. Synonym: ala vomeris. (05 Mar 2000) |
| RNA, transfer, ala | A transfer RNA which is specific for carrying alanine to sites on the ribosomes in preparation for protein synthesis. (12 Dec 1998) |
| area centralis | An oval area of the sensory retina, 3 by 5 mm, temporal to the optic disk corresponding to the posterior pole of the eye; at its centre is the central fovea, which contains only retinal cones. Synonym: area centralis, macula lutea, macular area, punctum luteum, Soemmerring's spot, yellow spot. (05 Mar 2000) |
| arteria centralis brevis | <anatomy, artery> A branch of the precommunical part of the anterior cerebral artery. Synonym: arteria centralis brevis. (05 Mar 2000) |
| arteria centralis longa | <anatomy, artery> Arises at or just distal to the anterior communicating artery; distribution: anterior caudate and putamen and anterior limb of internal capsule. Synonym: arteria centralis longa, arteria recurrens, artery of Heubner, long central artery, recurrent artery of Heubner, recurrent artery. (05 Mar 2000) |
| arteria centralis retinae | A branch of the ophthalmic artery which penetrates the optic nerve 1 cm behind the eye to enter the eye at the optic papilla in the retina; it divides into superior and inferior temporal and nasal branches. Synonym: arteria centralis retinae, arteria retinae centralis, Zinn's artery. (05 Mar 2000) |