| false projection | <ophthalmology> The faulty visual sensation arising secondarily to underaction of an ocular muscle. Synonym: erroneous projection. (05 Mar 2000) |
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| Fischer projection formula | <biochemistry> Of sugars, representations, by projection, of cyclic sugars, or derivatives thereof, in which the carbon chain is depicted vertically. The lowest-numbered asymmetric carbon atom (C-1 in aldoses; C-2 in 2-ketoses, e.g., fructose) is drawn at the top, and the rest of the carbon atoms of the chain are drawn in sequence below the top carbon atom. For each carbon atom, depicted in projection as lying in the plane of the paper, the carbon-to-carbon bond(s), which actually point away from the viewer, are drawn as vertical lines. The left-hand and right-hand bonds of each carbon atom, which actually point toward the viewer, are, in projection, depicted as horizontal lines. The conventions for the Fischer formulas of cyclic sugars are as follows: 1) if the highest-numbered asymmetric carbon atom has its OH (or its replacement) lying to the right, as is the 2-OH of d-glyceraldehyde, the sugar has the d configuration; if the OH is to the left, the sugar has the l configuration. 2) On the anomeric carbon atom (C-1 in the aldoses; C-2 in the 2-ketoses), an OH or substituted OH that lies to the right, with the OH of the highest-numbered asymmetric carbon atom also to the right is defined to be a; if it is to the left, with the OH of the highest-numbered carbon atom still to the right, it is b; the reverse applies if the latter OH is to the left. 3) The orientation of a terminal CH2OH group in the aldoses carries no configurational significance, as it contains no asymmetric carbon atom. (05 Mar 2000) |
| lateral projection | Radiographic projection with the X-ray beam in a coronal plane. (05 Mar 2000) |
| frog-leg lateral projection | A lateral projection of the femoral neck made with the thigh maximally abducted. (05 Mar 2000) |
| ascending frontal convolution | Bounded posteriorly by the central sulcus and anteriorly by the precentral sulcus. Synonym: gyrus precentralis, anterior central convolution, anterior central gyrus, ascending frontal convolution, ascending frontal gyrus. (05 Mar 2000) |
| ascending frontal gyrus | Bounded posteriorly by the central sulcus and anteriorly by the precentral sulcus. Synonym: gyrus precentralis, anterior central convolution, anterior central gyrus, ascending frontal convolution, ascending frontal gyrus. (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) |
| caecal 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) |
| parietal border of frontal bone | The margin of the frontal bone that articulates with the parietal bone. Synonym: margo parietalis ossis frontalis. (05 Mar 2000) |
| median frontal sulcus | A relatively shallow sagittal fissure of the brain dividing the middle frontal convolution into an upper and lower part; this sulcus is found only in humans and anthropoid apes; at its anterior extremity it bifurcates, the two branches spreading out laterally and constituting the frontomarginal sulcus. Synonym: median frontal sulcus, sulcus frontalis medius. (05 Mar 2000) |
| middle frontal convolution | A convolution on the convexity of each frontal lobe of the cerebrum running in an anteroposterior direction between the superior and inferior frontal sulci. Synonym: gyrus frontalis medius, middle frontal convolution. (05 Mar 2000) |
| middle frontal gyrus | A convolution on the convexity of each frontal lobe of the cerebrum running in an anteroposterior direction between the superior and inferior frontal sulci. Synonym: gyrus frontalis medius, middle frontal convolution. (05 Mar 2000) |
| middle frontal sulcus | A relatively shallow sagittal fissure of the brain dividing the middle frontal convolution into an upper and lower part; this sulcus is found only in humans and anthropoid apes; at its anterior extremity it bifurcates, the two branches spreading out laterally and constituting the frontomarginal sulcus. Synonym: median frontal sulcus, sulcus frontalis medius. (05 Mar 2000) |
| septum of frontal sinuses | The bony partition between the right and left frontal sinuses; it is often deflected to one side of the middle line. Synonym: septum sinuum frontalium. (05 Mar 2000) |
| squamous part of frontal bone | The broad curved portion of the frontal bone forming the forehead. Synonym: squama frontalis. (05 Mar 2000) |