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.

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] .
References in periodicals archive ?
Shang et al., "Multipotential differentiation of human anulus fibrosus cells: an in vitro study," The Journal of Bone and Joint Surgery-American Volume, vol.
Pichika et al., "Platelet-rich plasma (PRP) stimulates the extracellular matrix metabolism of porcine nucleus pulposus and anulus fibrosus cells cultured in alginate beads," Spine, vol.
Bir Wilson hastasinda da intervertebral diskte kalsiyum pirofosfat dihidratin fokal birikimi histokimyasal ve patoloji calismalariyla gosterilmis, birikimin hem anulus fibrosus hem de nukleus pulposusta bulundugu, en yogun olarak disk ile vertebral son plak arasindaki yuzde konsantre oldugu belirlenmistir.
Exposure of the nucleus pulposus to the outside of the anulus fibrosus induces nerve injury and regeneration of the afferent fibers innervating the lumbar intervertebral discs in rats.
Some scholars thought the scar tissue around dura mater of the spinal cord was originated from the posterior injured sacrospinalis and the anterior injured anulus fibrosus as well as the posterior longitudinal ligament.
Mow, "Degeneration affects the anisotropic and nonlinear behaviors of human anulus fibrosus in compression," Journal of Biomechanics, vol.
Weidenbaum, "Degeneration and aging affect the tensile behavior of human lumbar anulus fibrosus," Spine, vol.
Specifically, water is incompressible and therefore the nucleus pulposus (i.e., approximately 70%-90% water) exerts pressure in all directions on the surrounding rings of the anulus fibrosus through a process known as radial expansion [13,14].
As for other movements, axial rotation and/or side-bending will result in torsional forces applied to the lumbar IVDs, and resisted by the nature of the rings of the anulus fibrosus [13,14].
Appropriate antibiotic therapy usually results in a fall in the erythrocyte sedimentation rate, yet this was not seen in our patient, further evidence of the lack of an antibiotic response.[1] Interestingly, animal research has suggested that cefazolin can penetrate the intervertebral disc through the anulus fibrosus, yet may be unable to affect the course of the discitis.[9] This finding may have resulted from the rapid multiplication of bacteria within the disc and the inability of the relatively small concentration of antibiotic in the disc to effectively eradicate the organism.
Investigation of the laminate structure of lumbar disc anulus fibrosus. Spine (Phila Pa 1976) 1990; 15:402-10.