Define nadir. nadir synonyms, nadir pronunciation, nadir translation, English dictionary definition of nadir. n. 1. Astronomy A point on the celestial sphere directly below the observer, diametrically opposite the zenith. 2. The lowest point: the nadir of their...
Annular tear â definition and causes. By Michael Perry, M.D. An annular tear is one of the most common degenerative spine conditions that develop with the natural aging process of the spine. In fact, many people over the age of 50 have an annular tear and never know it.
Mitral annular calcification (MAC) is a common degenerative process involving the fibrous annulus of the mitral valve.It is generally an incidental finding associated with aging, although it occasionally is prominent enough to cause significant left ventricular inflow obstruction and symptomatic mitral stenosis.itral annular calcification (MAC) is a common degenerative process involving the fibrous annulus of the mitral valve.