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.
Although annular calcification is associated with mitral regurgitation, this is usually trivial and asymptomatic. Calcification of the annulus can however impede AV nodal conduction and therefore lead to varying degrees of heart block.ompared to aortic valve calcification, calcification of the mitral annulus is not significantly associated with stenosis of the valve and it is no longer felt to represent an independent risk factor for stroke 1.