| OPLL | ossification of posterior longitudinal ligament |
|---|---|
| PLL | peripheral light loss; phase-locked loop; poly-L-lysine; pressure length loop; posterior longitudina... |
| riMLF | rostral interstitial median longitudinal fasciculus |
| T1 | longitudinal relaxation time |
| T1 | spin-lattice or longitudinal relaxation time; tricuspid first sound |
| 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) |
| axis | <botany> A stem, commonly used for the main stem of a whole plant or of an inflorescence. (09 Oct 1997) |
| axis bulbi externus | That part of the optic axis from the midpoint of anterior surface of the cornea to the posterior surface of the posterior pole of the external surface of the sclera. Synonym: axis bulbi externus. (05 Mar 2000) |
| axis bulbi internus | <anatomy> That part of the optic axis from the midpoint of the posterior surface of the cornea to the anterior surface of the retina opposite the posterior pole. Synonym: axis bulbi internus. (05 Mar 2000) |
| axis corpuscle | Axile corpuscle, the central portion of a tactile corpuscle. (05 Mar 2000) |
| axis, crystallographic | <microscopy> One of several imaginary lines assumed in describing the positions of the planes by which a crystal is bounded, the positions of the atoms in the structure of the crystal and the directions associated with vectorial and tensorial physical properties. (05 Aug 1998) |
| axis cylinder | An obsolete term for axon. (05 Mar 2000) |
| axis deviation | Deflection of the electrical axis of the heart to the right or left of the normal. See: left axis deviation, right axis deviation, axis. Synonym: axis shift. (05 Mar 2000) |
| axis fracture | <radiology> Incidence: 6% of cervical spine injuries, associated with atlas fractures in 8%, hyperflexion injury: odontoid fracture, type I avulsion of tip of odontoid (5-8%) difficult to detect, type II fracture through base of dens (54-67%) complication: nonunion, type III subdental injury (30-33%) prognosis: good, Differential diagnosis: os odontoideum, ossiculum terminale, hypoplasia/aplasia of dens, hyperextension injury: hangman's fracture (12 Dec 1998) |
| axis lentis | A line connecting the anterior and posterior poles of the lens of the eye. Synonym: axis lentis. (05 Mar 2000) |