What is a meniscus
Crescentic fibrocartilage structures
- that serve to deepen the articular surfaces of the tibia for reception of the femoral condyles -
What is the prevalent collagen in the menisci, in what percentage?
Type 1 - 90%
What other components form the menisci in addition to collagen?
Glycosaminoglycans
Glycoproteins
Fibroblasts
Elastin
Stoller classification of the meniscus
- Patchy areas of increased signal that do not touch the inferior and superior borders of the menisci represent grade I changes.
- Grade II changes typically have a linear configuration, but again they do not touch the superior and inferior surfaces. These signal changes probably represent the normal aging process in the menisci.
- Increased signal with a linear appearance that contacts one of the articular surfaces of the menisci is classified as grade III change and represents a true meniscal tear
What are the 4 main functions of the menisci
(1) load transmission across the joint,
(2) enhancement of articular conformity,
(3) distribution of synovial fluid across the articular surface,
(4) prevention of soft tissue impingement during joint motion.
What pariticular function does the posterior horn of the medial meniscus play in a ACL insufficiency?
Stabilize the joint (in ACL insufficiency).
The posterior horn acts as a wedge to help reduce anterior tibial translation
Why are medial posterior root tears important? What is a root lesion comparable to?
Root tears appear to produce the same functional changes as total medial meniscectomy
Where is the posterior horn of the medial meniscus placed in relation to the PCL?
Directly anterior to the PCL insertion
Where is the anterior horn of the medial meniscus placed in relation to the ACL?
7 mm anterior to the anterior margin of the ACL insertion
What connects the anterior horns of the two meniscus?
Transverse intermeniscal ligament
Which muscle insertion does the medial meniscus receive a contigent in its postero-medial part?
Semimembranosus via the capsule
Where the anterior horn of the lateral meniscus is attached?
Directly anterior to the lateral tibial tubercle and adjacent to the ACL
Where the posterior horn of the lateral meniscus is attached?
Directly posterior to the lateral tibial tubercle and adjacent and anterior to the posterior horn of the medial meniscus
What is the name of the meniscus-femoral ligaments?
Humphry and Wrisberg
What is the relationship between the meniscus-femoral ligaments with the PCL?
The ligament of Humphry passes anterior to the PCL, whereas the ligament of Wrisberg passes posterior to the PCL
What is interrupted attachment of the lateral meniscus?
Popliteal hiatus
