What Is the Medial Meniscus?

The medial meniscus is connected to the medial collateral ligament, with a large distance between the two ends, in the shape of a "C". The anterior horn is attached to the anterior medial side of the tibial condyle, which is located at the beginning of the anterior cruciate ligament and before the lateral meniscus anterior angle; the posterior horn is attached to the posterior intercondylar region , Located between the posterior horn of the lateral meniscus and the attachment point of the posterior cruciate ligament. The margin is connected to the joint capsule and the medial joint capsule ligament. The shape of the medial meniscus is narrow and wide at the front, and the edges are thick. The closer to the center, the thinner, especially the front part. Some people also have meniscuses with almost the same width at the front and rear.

The medial meniscus is connected to the medial collateral ligament, with a large distance between the two ends, in the shape of a "C". The anterior horn is attached to the anterior medial side of the tibial condyle, which is located at the beginning of the anterior cruciate ligament and before the lateral meniscus anterior angle; the posterior horn is attached to the posterior intercondylar region , Located between the posterior horn of the lateral meniscus and the attachment point of the posterior cruciate ligament. The margin is connected to the joint capsule and the medial joint capsule ligament. The shape of the medial meniscus is narrow and wide at the front, and the edges are thick. The closer to the center, the thinner, especially the front part. Some people also have meniscuses with almost the same width at the front and rear.

Chinese name

Medial meniscus

Foreign name

medial meniscus

Connected structure

Medial collateral ligament

Features

Thinner than outside

Injured people

badminton. Football and basketball players, etc.

Cross-section anatomy of the medial meniscus

The cross section of the intersacral uplift can better show the inner and outer menisci. The anterior part is the sacroiliac ligament and the inferior tarsal fat pad; the posterior part is the posterior knee muscle, and the middle part is the main structure in the knee joint. Around the anterior, posterior and outer edges, there is a tibial intercondylar bulge between the two condyles. The lateral meniscus is slightly "o" shaped. Its front end is attached to the anterior intercondylar region, and is located behind the anterior cruciate ligament attachment point. The two fibers are partially intertwined. At the junction, 1/3 of the plantar tendon passes, and the lateral fibular collateral ligament adjacent to it is not connected to the meniscus. A fiber bundle was divided in the posterior horn to participate in the posterior cruciate ligament. The medial meniscus had a large C-shaped front end attached to the anterior intercondylar ligament in the anterior intercondylar ligament. The bulge is behind the origin of the posterior cruciate ligament. The medial edge is connected to the joint capsule and the tibial collateral ligament. The tibial collateral ligament is located on the inside and the back of the tibial collateral ligament. The anterior and posterior angles of the medial meniscus front anterior cruciate ligament and lateral meniscus frontal tibial intercondylar bulge lateral medial meniscus posterior posterior cruciate ligament combined with sagittal coronal cross section were measured from front to back.

Mechanism of medial meniscus injury

Patients are porters, football and basketball players. Mine tunnel workers and army soldiers are more common, and are easily damaged during heavy physical work or sports.

When the knee joint is half flexed. The foot is fixed to the calf, the thigh and the trunk are subject to autoinertial force or lateral impact, causing the femoral condyle to rotate internally, the calf abduction and external rotation, and the medial meniscus is squeezed between the tibiofemoral joint and forced to the knee Center and rear side shift. Because the meniscus is tightly attached to the tibial plateau. The mobility is small, under the pressure of strong internal rotation of the femoral condyle and external rotation of the tibial condyle. The meniscus then ruptured. Topical meniscus Shuluoping pain patch when injured.

After the knee joint was ruptured, the reactive pain caused the patient to straighten the knee. Hold the knees for a stretch and flexion exercise, trying to restore the meniscus. However, due to muscle spasms and heavy body pressure, it is often difficult for the displaced and ruptured medial meniscus to fully reset, even if it is reset. It is also impossible to avoid the compression of the damaged part, which often aggravates the damage. It also causes damage to the articular surface of the femoral condyle.

Ruptured meniscus is more common as a longitudinal slit. The femoral condyle protrudes into the rupture opening and directly contacts the tibial plateau. The ruptured meniscus is stuck between the tibiofemoral joint surface, causing a movement disorder in one direction of the knee joint, so-called "joint interlocking". The patient must avoid weight bearing on the affected limb, and gradually reset the abnormal displacement and the rupture of the meniscus around the tibiofemoral joint contact with the help of a large valgus and medial knee flexion of the medial knee. After getting out of the bayonet, the knee joint is flexed again and again, this is called unlocking or "unlocking".

Medial meniscus injury type

1. Edge type: Rupture is located in front of the edge of the medial meniscus. In the middle and rear positions, the severe marginal rupture was completely perimeter rupture, connected only by the front and rear corners, and the ruptured waist slipped toward the center of the knee. And lead to joint lock. Symptoms are significant when the knee is extended. It is believed that this type has the potential to heal itself. Some also healed by sutures.

2. Anterior angle type: The rupture is located at the anterior corner, which can be only a nick, or it can be rolled backward and thickened as the rupture, and the anterior horn connection is also broken. The pain is located in front of the knee, but it may be indistinguishable between patients inside and outside.

3. Posterior corner type: The rupture is located in the posterior corner, which can be a slit. Fissures crease and posterior horn connective fibers break. Pain is noticeable when knee flexes excessively. Pain can be pointed to the back and inside, but there are a few that can't indicate the side.

4. Horizontal type: The medial meniscus waist ruptures transversely. The rupture site, number and depth are different. Pain in the medial knee can be indicated, with occasional joint interlocking.

5. Bucket handle type: the inner meniscus ruptures vertically, and the cracks can be of different sizes and have transverse cracks. The rupture opening was thickened significantly, and the femoral condyle synovium was extensively damaged. The affected knee often has "locking", which is laborious and time consuming.

6. Inner edge type: There is one or more injuries on the inner edge of the meniscus, and it can show comminuted damage. Occasionally, free pieces enter the joint cavity. This type often affects flexion and extension of the knee, showing pain over the years, obvious damage to the articular surface of the femoral condyle, and sometimes joint interlocking. X-ray plain films occasionally have free bone fragments.

7. Horizontal split type: The tibiofemoral joint rotates so strongly that the two layers of the medial meniscus are separated horizontally. If diagnosed early and well braked, repair may be possible. The affected knee may show dull pain, instability, or a feeling of slipping.

8. Longitudinal fissure type: The inner meniscus ruptures vertically. It can break at the front or back corner, and the free part enters the knee, becoming the main factor of knee pain and blocking of extension and flexion.

9. Loose type: The medial meniscus is loosened at the joint capsule attachment. Every time the knee stretches and flexes, there is an unstable slippery rotation. When the tibiofemoral joint is squeezed toward the center of the knee, the medial joint capsule (and skin) can sink into the joint space. This type can be caused by a trauma or a congenital structural defect.