Meniscus


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to Meniscus: meniscus tear

meniscus

1. the curved upper surface of a liquid standing in a tube, produced by the surface tension
2. a crescent-shaped fibrous cartilage between the bones at certain joints, esp at the knee
3. a crescent-shaped lens; a concavo-convex or convexo-concave lens

Meniscus

 

the crescent-shaped inner and outer intraarticular cartilages in the knee joint.

The menisci increase the congruence of the joint surfaces, making diversity of movement possible and softening the effect of impact. The menisci may be injured by forced movement connected with overextension of the joint (most often in athletes). When the menisci are detached, there is a sudden block of the joint; sharp pains result from strangulation of the detached parts and the impossibility of movement in the joint. Proper treatment (conservative or, when this proves unsuccessful, surgical) completely restores joint function. In other joints (for example, mandibular and radiocarpal) intraarticular cartilages with analagous functions are called disks.


Meniscus

 

in optics, a concavo-convex or convexo-concave lens bounded by two spherical surfaces; such a lens is one of the most widely used types of lenses. A meniscus whose thickness is greater at the center than at the edges (positive meniscus) is a converging lens, and a meniscus whose thickness is greater at the edges than at the center (negative meniscus) is a diverging lens. Menisci are used in various optical systems, for example, in eyeglasses, in the objectives of motion-picture cameras and still cameras, and as attachment lenses that change the focal lengths of objectives.

Meniscus systems have gained widespread use in applications that require a higher degree of correspondence between the optical image and the object, for example, in astronomy. In these systems, small distortions of the image introduced by the meniscus (aberrations) are compensated by aberrations introduced by other elements of the system. The result is that it is possible to obtain practically undistorted images. The inherent aberrations of the individual menisci may be reduced by the use of diaphragms (for example, in camera objectives, up to a relative aperture of 1:11).


Meniscus

 

the curved free surface of a liquid near the contact between the liquid and the surface of a solid. For example, a meniscus is formed at the walls of vessels and in the channels and pores of spongy materials impregnated with liquids. A meniscus has a spherical shape in thin (capillary) tubes and a cylindrical shape in a sufficiently narrow gap between flat plates. The curvature of the meniscus is determined by the relationship between the forces of molecular interaction at the triple point of the three phases—solid, liquid, and gas (or vapor). A liquid that wets a given surface forms a concave meniscus, whereas a liquid that does not wet the surface forms a convex meniscus. In the first case, the mutual attraction between the molecules of the liquid (cohesion) is weaker than the attraction of the molecules of the liquid by the molecules of the surface of the solid (adhesion). Conversely, in the second case, the forces of cohesion exceed the forces of adhesion. The vapor pressure over a concave meniscus is less than, and that over a convex meniscus is more than, the vapor pressure over a plane liquid surface. This explains such phenomena as capillary condensation, capillary absorption of a liquid in porous and fibrous materials, and the rising and falling of liquids in thin pipes.

meniscus

[mə′nis·kəs]
(anatomy)
A crescent-shaped body, especially an interarticular cartilage.
(fluid mechanics)
The free surface of a liquid which is near the walls of a vessel and which is curved because of surface tension.
(metallurgy)
In reference to a solder joint, the minimum angle at which the solder tapers from the joint to the flat area.
References in periodicals archive ?
Founded in late 2011, Ivy Sports Medicine is a privately held orthopedic device company that develops, manufactures and markets innovative tissue growth and repair products that focus on preservation of the meniscus.
We believe that the usability improvements in this new device will enable surgeons to provide meniscus repair to an even broader set of patients who need better solutions for this very common knee injury.
Only 10% to 30% of the medial meniscus and 10% to 25% of the lateral meniscus are vascularized.
Football is followed by the athletism, american football and skiing among the causes of meniscus tears [19, 20].
It was a long comeback for the ACL -- the meniscus (recovery) was shorter, but it's just as much of a mental battle as your ACL,'' Farina said.
There are reported cases of complete absence of the medial meniscus as described in thrombocytopenia absent radius syndrome (TAR syndrome).
One study participant -- Bob O'Keefe, 68, of suburban Boston -- was glad to avoid surgery for his meniscus injury three years ago.
Meniscus will publish advance reviews of films, and updates leading up to and throughout the festival across various social media networks, including Twitter, Facebook, Google+ and Foursquare (our page includes tips on things to see and do in San Diego during the SDAFF).
Stone reported that their peer-reviewed prospective study in the Journal of Bone and Joint Surgery proved that a meniscus transplant combined with an articular cartilage stem cell paste graft procedure can delay knee replacement for an average of 9.
However, the meniscus function of this compressive reinforced PVA-H has not been confirmed yet.
For patients, it matters because repaired meniscus tears have a more involved recovery compared with surgical removal of the tissue.
Researchers have said that having more precise information about wear and tear on this portion of the knee - a blend of fibrous tissue and cartilage called the meniscus - could lead to its use as a biomarker in predicting who is at risk for developing osteoarthritis.