What is the meniscus?
The meniscus is a flat cartilage in the knee joint that thickens towards the outside. Each knee contains an inner meniscus (meniscus medialis) and a smaller outer meniscus (m. lateralis).
The rather tight, pressure-resistant interarticular discs made of connective tissue and fibrocartilage are easily movable. Due to their crescent shape, the femur and tibia meet only in the middle of the joint.
Movement supplies the meniscus
With these small changes in position, the menisci cause the synovial fluid, which is so important for supplying the cartilage, to be distributed and mixed. Since the meniscus in adults is only supplied with blood in its peripheral areas, the direct absorption of nutrients or the release of waste products is only possible there. In the rest of the meniscus, this must occur through pressure and pressure relief (diffusion).
What is the function of the meniscus?
Less friction
Due to its smooth surface, cartilage basically reduces friction. The meniscus does the same: it ensures less friction between the joint head and the socket in the knee. In this way, the roll-slide motion of the femur over the tibia bone is smoother.
Better weight and pressure distribution
Shock absorption
The menisci take on about one third of the load transmitted in the knee joint. Their tight and compression-resistant nature (viscoelastic) makes them suitable shock absorbers that effectively cushion shocks during walking, running and jumping.
Where is the meniscus located?
The two cartilage discs are located in the knee joint between the thigh bone (femur) and the shin bone (tibia). They lie on the tibial plateau as if on a tabletop and cover about 70 percent of it.
The menisci are surrounded by ligaments and tendons. Only the medial meniscus is fused to the lateral ligament. At the front, the two menisci are connected by a strong retaining ligament (ligamentum transversum genus).
Knee problems originating from the menisci manifest themselves in the form of pain or knee block. Either the cartilage disc is jammed, torn or degenerated. The first signs of wear can become apparent in the form of a connective tissue cyst, the meniscus ganglion.
In rare cases, benign or malignant neoplasms occur on the cartilage discs. Children can sometimes have malformed menisci (disc meniscus).
The problem with a meniscus injury (as with any cartilage) is that the shock absorbers can only regenerate themselves to a limited extent.
