Alphabetical list

FMC rules and notations
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Lateral ( Barclay, 1803 ) : Away from the median plane (Henle, 1855) of the body, in the frontal plane (Henle, 1855); the opposite of medial (Schulze, 1893). Use of the term seems to go at least as far back as the second century and Galen (see, for example, translation by May, 1968, p. 701), but its formal use was introduced by Barclay (1803, pp. 121, 163), who paired it with mesial. Also see Brusca & Brusca (1990, Fig. 4-A). more details

Lateral ventricles ( VL ; Vesalius, 1543 ) : The part of the ventricles (Hippocrates) in the right and left endbrain (Kuhlenbeck, 1927); they communicate with the unitary third ventricle (Galen, c173) through the interventricular foramina (one for each lateral ventricle). They correspond to the first and second ventricles, were known in macrodissected adult humans to Erasistratus (c310-c250 BC; see Clarke & O'Malley, 1996, p. 12), and were named such by Vesalius (1543; see translation by Singer, 1952, pp. 41, 68). more details

Leptomeninges : The pia (Galen, c192) and arachnoid (Blasius, 1666) considered together; see Standring (2008, p. 389). more details

Local connection : Often a synonym for intraregional connection, though its meaning can be vague and its use is thus discouraged. more details

Local tract : A white matter tract having a short course entirely within a gray matter region. more details

Longitudinal axis ( Barclay, 1803 ) : The oral-aboral axis (Schulze, 1893) of the body in all animals with a nervous system (Monro, 1783); term probably introduced by Barclay (1803, p. 117); also see Henle (1855, p. 1), Willmer (1990, p. 15). Other synonyms include rostrocaudal axis, central axis, long axis, midsagittal axis, principal axis, and anteroposterior axis, the latter being discouraged as especially ambiguous in comparative anatomy. The longitudinal axis is orthogonal to the transverse axis (Henle, 1855). The concept was clearly described by Aristotle in De Partibus Animalium, where he wrote that "a straight line as an axis has at the upper end the mouth, followed by the gullet, stomach, intestine, and excremental vent"; and that furthermore in some animals like humans, quadrupeds, crustacea, and insects the axis is essentially straight, whereas at the other extreme in animals like the Cephalopods it can be highly curved and thus U-shaped; see translation by Ogle (1912, 685a-686b). Kuhlenbeck (1973, p. 111) provided a nice modern statement of the concept: "Three so-called "axial lines" [longitudinal or rostrocaudal, dorsoventral, and mediolateral] which can be conceived as geodesics and therefore not necessarily ‘straight', provides an essentially nonmetric and non-Euclidean (Euclidoid), ameboid three-dimensional coordinate system (German: "Bezungsmollusk") of anatomical space…" more details

Longitudinal plane ( Henle, 1855 ) : A plane of section passing through the longitudinal axis (Barclay, 1803) in animals with radial symmetry, dividing the body into roughly equal longitudinal halves; term alluded to by Henle (1855, p. 1). In animals with bilateral symmetry there are two orthogonal longitudinal planes, the sagittal plane (Henle, 1855) and frontal plane (Henle, 1855). A synonym is rostrocaudal plane. more details

Longitudinal tract : A white matter tract coursing essentially along the longitudinal axis (Barclay, 1803) of the nervous system (Monro, 1783); if a longitudinal tract crosses the median plane (Henle, 1855) in an animal with bilateral symmetry, the segment related to that plane is a decussation. The basically transverse and longitudinal organization of nervous system tracts was emphasized early on by Spencer (1881) and Cajal (1899-1904, vol. 1, p. 12), and more recently in the orthogon theory of Reisinger (1925, 1972). more details

Loop : Typically and logically it is synonymous with closed chain. more details