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 The common tendinous ring, also known as the annulus of Zinn, or annular tendon, is a ring of fibrous tissue surrounding the optic nerve at its entrance at the apex of the orbit. It is the common origin of the four recti muscles of the group of ex ...

, a.k.a. annular tendon or ''anulus tendineus communis'', around the optic nerve *

Annular ligament (disambiguation) Annular ligament may refer to: * Zona orbicularis, Annular ligament of femur * Annular ligaments of fingers * Annular ligament of radius *Annular ligament of stapes (also known as the stapediovestibular joint) * Annular ligaments of trachea * Annul ...

* ''Digitus anularis'', a.k.a. ring finger * ''Anulus ciliaris'', a.k.a.

ciliary body The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor. The aqueous humor is produced in the non-pigmented portion of the ciliar ...

* ''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) 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 com ...

, outer gear ring in an

epicyclic gearing An epicyclic gear train (also known as a planetary gearset) consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers of the two gears and rotates the planet and sun gea ...

Annulus (botany) {{Short description, A ring of specialized cells on the sporangium An annulus in botany is an arc or a ring of specialized cells on the sporangium. These cells are arranged in a single row, and are associated with the release or dispersal of spores. ...

, 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

Human anatomy

Other

See also