anulus fibrosus

anulus

 [an´u-lus] (pl. a´nuli) (L.) a small ring or encircling structure; also spelled annulus.anulus fibro´sus 1. fibrous ring of heart; any of four dense fibrous rings, one of which surrounds each of the major cardiac orifices.2. fibrous ring of intervertebral disk; the circumferential ringlike portion of an intervertebral disk.anulus of spermatozoon a dark ringlike structure at the posterior end of the middle piece of a spermatozoon. Called also ring centriole.

(right and left) fi·brous rings of heart

[TA] two fibrous rings that surround atrioventricular orifices of the heart, providing attachment for the atrioventricular valve leaflets and maintaining patency of the orifices. As part of the fibrous skeleton of the heart, the fibrous rings also provide origin and insertion for the myocardium. Synonym(s): anulus fibrosus (1) [TA], anulus fibrosus dexter/sinister cordis, coronary tendon, fibrous ring (1) , Lower ring

an·u·lus fi·bro·sus of in·ter·ver·te·bral disc

(an'yū-lŭs fī-brō-sŭs in-tĕr-vĕr'tĕ-brăl disk) [TA] The ring of fibrocartilage and fibrous tissue forming the circumference of the intervertebral disc; surrounds the nucleus pulposus, which can herniate when the anulus is diseased or injured.
Synonym(s): anulus fibrosus disci intervertebralis [TA] , anulus fibrosus (2) [TA] .

right and left fi·brous rings of heart

(rīt left fī'brŭs ringz hahrt) Two fibrous rings that surround the atrioventricular orifices of the heart, providing attachment for the atrioventricular valve leaflets and maintaining patency of the orifices. As part of the fibrous skeleton of the heart, the fibrous rings also provide origin and insertion for the myocardium.
Synonym(s): anulus fibrosus (1) [TA] .