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.
Annulus: A ringlike structure, or any body part that is shaped like a ring. Applied to many small ring-shaped structures. The base of a heart valve that supports the valve's leaflets is called the annulus. A ring-shaped pancreas that encircles the duodenum is an annular pancreas. Annulus is a misspelling of the Latin anulus (a little ring), the diminutive of the Latin anus (a ring of more substantial size).