| Mz | longitudinal magnetization |
|---|---|
| OALL | ossification of anterior longitudinal ligament |
| OPLL | ossification of posterior longitudinal ligament |
| PLL | peripheral light loss; phase-locked loop; poly-L-lysine; pressure length loop; posterior longitudina... |
| T1 | longitudinal relaxation time |
| longitudinal magnification | <microscopy> A certain distance, measured axially, in the object space as referred to the respective distance in the image space. The ratio of the distance D' in the image space to the distance D in the object space equated to the square of the linear magnification M of the system. Thus: M exp2 =D'/D. (05 Aug 1998) |
|---|---|
| longitudinal method | In developmental psychology, the study of the life span of one individual involving comparisons of different age levels. Compare: cross-sectional method. (05 Mar 2000) |
| longitudinal oval pelvis | A pelvis in which the anteroposterior diameter is longer than the transverse. Synonym: longitudinal oval pelvis. (05 Mar 2000) |
| longitudinal pontine bundles | The massive bundles of corticofugal fibres passing longitudinally through the ventral part of pons; they are composed of corticopontine, corticobulbar, and corticospinal fibres. Synonym: fasciculi longitudinales pontis, longitudinal pontine bundles. (05 Mar 2000) |
| longitudinal pontine fasciculi | The massive bundles of corticofugal fibres passing longitudinally through the ventral part of pons; they are composed of corticopontine, corticobulbar, and corticospinal fibres. Synonym: fasciculi longitudinales pontis, longitudinal pontine bundles. (05 Mar 2000) |
| longitudinal relaxation | In nuclear magnetic resonance, the return of the magnetic dipoles of the hydrogen nuclei (magnetization vector) to equilibrium parallel to the magnetic field, after they have been flipped 90 |
| longitudinal section | A section that is cut along the long axis of a structure. The opposite is a cross-section. (12 Dec 1998) |
| longitudinal sinus | See: inferior sagittal sinus, superior sagittal sinus. Longitudinal vertebral venous sinus, large, plexiform veins forming portions of the anterior internal vertebral venous plexus lying on the posterior surfaces of the vertebral bodies on either side of the posterior longitudinal ligament. Synonym: sinus vertebrales longitudinales. Luschka's sinus, venous sinus in the petrosquamous suture. (05 Mar 2000) |
| longitudinal studies | Studies in which variables relating to an individual or group of individuals are assessed over a period of time. (12 Dec 1998) |
| longitudinal study | <epidemiology> A study taking place over time. If individuals are followed, this is a longitudinal cohort study. If individuals are not followed, but classes (usually age classes) are restudied, this is a longitudinal cross-sectional study. The converse of a horizontal study. (05 Dec 1998) |
| longitudinal sulcus of heart | See: anterior interventricular groove, posterior interventricular groove. (05 Mar 2000) |
| longitudinal wave | <physics> Waves where the variation of the field is partially or totally in the direction of propagation (parallel to wavennumber, k [a vector]). Examples include sound waves and Langmuir waves. Contrasted with transverse waves, where the variation is perpendicular to the direction of propagation, such as light waves. (13 Nov 1997) |
| anterior pyramidal fasciculus | Uncrossed fibres forming a small bundle in the pyramidal tract. See: pyramidal tract. Synonym: tractus corticospinalis anterior, tractus pyramidalis anterior, anterior corticospinal tract, anterior pyramidal fasciculus, direct pyramidal tract, fasciculus corticospinalis anterior, fasciculus pyramidalis anterior, Turck's bundle, Turck's column, Turck's tract. (05 Mar 2000) |
| arcuate fasciculus | Long association fibre bundle lateral to the centrum ovale of the cerebral hemisphere, connecting the frontal, occipital, and temporal lobes; the fibres pass from the frontal lobe through the operculum to the posterior end of the lateral sulcus where many fibres radiate into the occipital lobe and others turn downward and forward around the putamen and pass to anterior portions of the temporal lobe. Synonym: fasciculus longitudinalis superior, arcuate fasciculus. (05 Mar 2000) |
| Burdach's fasciculus | The larger lateral subdivision of the posterior funiculus. Synonym: fasciculus cuneatus, Burdach's column, Burdach's fasciculus, Burdach's tract, cuneate funiculus, wedge-shaped fasciculus. (05 Mar 2000) |