Cartilage Flashcards
1
Q
What is the functions of the menisci?
A
- distribute load
- stabilise the joint
- shock absorption
- lubrication
- proprioception
2
Q
Describe the gross structure of the menisci
A
- wedge-shaped cross section (increases contact area between tibia and femur)
- horns of the menisci attached to the tibia
- outer rim of the medial meniscus is attached to the joint capsule (less mobile=more likely to injure)
- posterior horn of lateral meniscus is attached to the femur via the meniscofemoral ligaments
- lateral meniscus covers relatively more of its tibial plateau (>75% vs 50-75%)
3
Q
Describe the histology of the menisci.
A
- comprised of ~70% water, ~25% collagen type 1 and 1-2% proteoglycans
- mature cells are fibroblasts & chondrocytes
- PG concentration is greater in inner ⅔ (attract and bind water to assist lubrication)
- inner zone collagen arrangement is radial (resists compressive forces)
- outer zone collagen arrangement is circumferential (resists tensile forces)
- outer ⅓ is vascularised (better healing capacity)
- outer ⅓ is innervated and contains mechanoreceptors in the horns (proprioception)
4
Q
Describe some mechanical properties of the menisci.
A
- high tensile modulus
- during knee flexion the menisci translate posteriorly relative to the tibia (to maintain contact area and reduce stress)
5
Q
Describe 4 ways the behaviour of fibrocartilage differs from hyaline.
A
- fibrocartilage has a higher tensile modulus and higher tensile ultimate stress
- hyaline has a higher compressive modulus and higher compressive ultimate stress
- hyaline has a higher shear modulus
- fibrocartilage has a higher shear ultimate stress
5
Q
Describe 4 ways the behaviour of fibrocartilage differs from hyaline.
A
- fibrocartilage has a higher tensile modulus and higher tensile ultimate stress
- hyaline has a higher compressive modulus and higher compressive ultimate stress
- hyaline has a higher shear modulus
- fibrocartilage has a higher shear ultimate stress
