Annulus (or anulus) or annular indicates a ring- or donut-shaped area or structure. It may refer to:
Human anatomy
* ''
Anulus fibrosus disci intervertebralis'', spinal structure
*
Annulus of Zinn, a.k.a. annular tendon or ''anulus tendineus communis'', around the optic nerve
*
Annular ligament (disambiguation)
* ''Digitus anularis'', a.k.a.
ring finger
* ''Anulus ciliaris'', a.k.a.
ciliary body
* ''Anulus femoralis'', a.k.a.
femoral ring
* ''Anulus inguinalis superficialis'', a.k.a.
superficial inguinal ring
The inguinal canals are the two passages in the anterior abdominal wall of humans and animals which in males convey the spermatic cords and in females the round ligament of the uterus. The inguinal canals are larger and more prominent in males. Th ...
* ''Anulus inguinalis profundus'', a.k.a.
deep inguinal ring
* ''Anuli fibrosi cordis'', a.k.a.
fibrous rings of heart
* ''Anulus umbilicalis '', a.k.a.
umbilical ring
The umbilical ring is a dense fibrous ring surrounding the Navel, umbilicus at birth. At about the sixth week of embryological development, the midgut herniates through the umbilical ring; six weeks later it returns to the abdominal cavity and rot ...
Other
*
Annulus (construction), outer gear ring in an
epicyclic gearing
*
Annulus (botany), structure on fern and moss sporangia
*
Annular lake, a ring-shaped lake caused by meteor impact
*
Annulus (mathematics)
In mathematics, an annulus (plural annuli or annuluses) is the region between two concentric circles. Informally, it is shaped like a ring or a hardware washer. The word "annulus" is borrowed from the Latin word ''anulus'' or ''annulus'' mean ...
, the shape between two concentric circles
*
Annulus (mycology)
An annulus is the ring-like or collar-like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remnants of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. ...
, structure on mushroom
*
Annulus (firestop), site of construction issue
*
Annular piston, a ring-shaped piston
*
Annulus (well), void between concentric cylinders
*
Annular blowout preventer, device for sealing oil and gas wells
*
Annulation, type of ring-producing chemical reaction
See also
*
*
*
Annulet (disambiguation)
*
Annular eclipse
*
Annular tropical cyclone
* Annular combustor,
design option in engine
*
Ring (disambiguation)
{{disambiguation