Meniscus (anatomy)

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A meniscus is a crescent-shaped fibrocartilagin anatomical structure, in contrast to an articular disk, only partly dividing the joint cavity. In humans they are present in the knees, wrists, acromioclavicular joints, sternoclavicular, and temporomandibular; in other animals they can be present in other joints.

Generally, the term 'meniscus' is used to refer to the knee cartilage, either to the lateral or medial meniscus. Both are cartilage tissues that provide structural integrity to the knee while experiencing tension and torsion. Menisci is also known as the "semi-lunar" cartilage, referring to their crescent moon, the shape of the crescent moon.

The term meniscus comes from the ancient Greek ???????? (meniskos) , which means 'sickle'.

Video Meniscus (anatomy)

Structure

Meniscus of the knee are two fibrocartilaginous tissue pads that serve to dissolve friction on the knee joint between the lower limb (tibia) and thigh (femur). They are concave at the top and flat at the bottom, articulate with the tibia. They attach to a small depression (fossae) between the tibia condus (the intercondyloid fossa), and toward their unbound center and the shape narrows to a thin shelf. Meniscus blood flow comes from the periphery (outer) to the central meniscus. Blood flow decreases with age and central meniscus is avascular in adulthood, leading to very poor healing rates.

Maps Meniscus (anatomy)

Function

The menisci acts to dissolve the body weight and reduce friction while moving. Because the condyle of the femur and tibia meet at one point (which changes during flexion and extension), menisci spreads the weight of the body. This differs from the sesamoid bone, which is made up of osseous tissue and its main function is to protect nearby tendons and to enhance its mechanical effect.

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Clinical interests

Injuries

In sports and orthopedics, people sometimes talk about "torn cartilage" and actually refer to injuries to one of the menisci. There are two common types of meniscal injuries, acute tears that often occur due to trauma or sports injuries and chronic or wear tear. Acute tears have many forms (vertical, horizontal, radial, oblique, complex) and size. They are often treated with surgical repair depending on the age of the patient because they rarely heal themselves. Chronic tears are treated symptomatically: physical therapy with or without the addition of injections and anti-inflammatory drugs. If tears cause persistent pain, swelling, or knee dysfunction, a tear can be removed or repaired surgically. An unhappy triad is a set of commonly occurring knee injuries that include injury to the medial meniscus.

Conservative management

Conservative management is often considered first for smaller or chronic tears that do not seem to be suitable for surgical repair. It consists of activity modification, physical therapy to strengthen and various movements, electro-acupuncture.

Surgical treatment

Two meniscus surgeries are the most common. Depending on the type and location of the tear, the age of the patient, and the preference of the physician, injuring the meniscus is usually either repaired or removed, partially or completely (menisectomy). Each has advantages and disadvantages. Many studies show that meniscus has a purpose and therefore doctors will try to improve it whenever possible. However, meniscus has a poor blood supply, and, therefore, healing can be difficult. Traditionally it is considered that if there is no chance of healing, then it is best to remove the damaged and non-functioning meniscus, although at least one study has shown that there is no significance if menisectomy is performed. However, continuing high intensity activities may be impossible without surgery because tears may be flapping around, causing the knee to be locked.

The 2017 clinical practice guidelines strongly recommend not to perform surgery in almost all patients with degenerative knee disease.

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Etymology

The term meniscus comes from the Greek ???????? meniskos , "sickle". Meniskos (????????), "little moon", small of ????, "moon". The word is also used for curving in general, such as necklaces or battle lines.