| PR | by way of the rectum [Lat. per rectum]; far point [of accommodation] [Lat. punctum remotum]; palindr... |
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| PT | pain threshold; parathormone; parathyroid; paroxysmal tachycardia; part time; patient; pericardial t... |
| ALS | acute lateral sclerosis; advanced life support; afferent loop syndrome; amyotrophic lateral sclerosi... |
| LGN | lateral geniculate nucleus; lateral glomerulonephritis |
| LL | large lymphocyte; lateral leminiscus; left lateral; left leg; left lower; left lung; lepromatous [in... |
| pyramidal decussation | The intercrossing of the bundles of the pyramidal tracts at the lower border region of the medulla oblongata. Synonym: decussatio pyramidum, decussatio motoria, motor decussation. (05 Mar 2000) |
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| pyramidal disease | A condition of the horse's foot in which there is exostosis of the extensor process of the third phalanx, with swelling and chronic inflammation at the coronary band on the anterior surface of the foot. Synonym: pyramidal disease. (05 Mar 2000) |
| pyramidal eminence | A conical projection posterior to the vestibular window in the middle ear; it is hollow and contains the stapedius muscle. Synonym: pyramid of tympanum, pyramidal eminence, pyramis tympani. (05 Mar 2000) |
| pyramidal fibres | The fibres that compose the pyramidal tract (corticospinalis). Synonym: fibrae corticospinales, corticospinal fibres, fibrae pyramidales. (05 Mar 2000) |
| pyramidal fracture | A fracture of the midfacial skeleton with the principal fracture lines meeting at an apex at or near the superior aspect of the nasal bones. Synonym: Le Fort II fracture. (05 Mar 2000) |
| pyramidal lobe of thyroid gland | <anatomy> An inconstant narrow lobe of the thyroid gland that arises from the upper border of the isthmus and extends upward, sometimes as far as the hyoid bone; it marks the point of continuity with the thyroglossal duct. Synonym: lobus pyramidalis glandulae thyroideae, Lallouette's pyramid, Morgagni's appendix, pyramid of thyroid. (05 Mar 2000) |
| pyramidal muscle | <anatomy, muscle> Origin, crest of pubis; insertion, lower portion of linea alba; action, makes linea alba tense; nerve supply, subcostal. Synonym: musculus pyramidalis, pyramidal muscle. (05 Mar 2000) |
| pyramidal muscle of auricle | <anatomy> An occasional prolongation of the fibres of the tragicus to the spina helicis. Synonym: musculus pyramidalis auriculae, Jung's muscle, pyramidal muscle of auricle. (05 Mar 2000) |
| pyramidal process | The portion of the palatine bone passing lateral and posterior from the angle formed by the vertical and horizontal plates. Synonym: processus pyramidalis. (05 Mar 2000) |
| pyramidal radiation | Corticospinal fibres passing from the cortex into the pyramid. Synonym: radiatio pyramidalis. (05 Mar 2000) |
| pyramidal tract | A massive bundle of fibres originating from pyramidal cells of various sizes in the fifth layer of the precentral motor (area 4), the premotor area (area 6), and to a lesser extent from the postcentral gyrus. Cells of origin in area 4 include the gigantopyramidal cells of Betz. Fibres from these cortical regions descend through the internal capsule, the middle third of the crus cerebri, and the ventral part of the pons to emerge on the ventral surface of the medulla oblongata as the pyramis. Continuing caudally, most of the fibres cross to the opposite side in the pyramidal decussation and descend in the dorsal half of the lateral funiculus of the spinal cord as the lateral pyramidal tract, which distributes its fibres throughout the length of the spinal cord to interneurons of the zona intermedia of the spinal gray matter. In the (extremity-related) spinal cord enlargements, fibres also pass directly to motoneuronal groups that innervate distal extremity muscles subserving particular hand-and-finger or foot-and-toe movements. The uncrossed fibres form a small bundle, the anterior pyramidal tract, which descends in the anterior funiculus of the spinal cord and terminates in synaptic contact with interneurons in the medial half of the anterior horn on both sides of the spinal cord. Interruption of the pyramidal tract at or below its cortical origin causes impairment of movement in the opposite body-half, especially severe in the arm and leg; characterised by muscular weakness, spasticity and hyperreflexia, and a loss of discrete finger and hand movements. Babinski's sign is associated with this condition of hemiplegia. Synonym: tractus corticospinalis, tractus pyramidalis, corticospinal tract. (05 Mar 2000) |
| pyramidal tractotomy | May be mesencephalic (pedunculotomy or crusotomy), medullary (medullary pyramidotomy), or spinal (spinal pyramidotomy). (05 Mar 2000) |
| direct pyramidal tract | 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) |