Joints Flashcards
What are the functions of the Synovial joint
Bone ends Articular cartilage Joint capsule Joint Cavity Synovial membrane Ligaments
Articular cartilage
This covers bones and joints. It is like hyaline cartilage, but it has no perichondrium and its matrix contains more water than other cartilage
Joint capsule?
Is a sac that encloses the articulating ends of the bones in the joint. It is made up of an outer fibrous layer and an inner synovial membrane. It may reinforce with accessory structures such as tendons or ligaments.
Synovial membrane?
Lines the interior of the joint capsule and secretes synovial fluid into the joint cavity.
Joint cavity?
Contains synovial fluid. This fluid as as a lubricant, cushions shocks, prevents abrasion and supports the chondrocytes of the articular cartilages. Even in a large joint such as the knee, the total volume of synovial fluid in a joint is normally less than 3mL.
Synovial fluid structures
Lubrication
Nutrient distribution
Shock absorption
Structures supporting the knee:
Bursa
Fat pads
Meniscus
Ligaments
Ligaments supporting the knee:
Capsular ligament- Holds bone together, tight and thick where more support is required, loose where movement is allowed and potential space or cavity.
Collateral ligaments
- Medial collateral ligament ( connects femur to tibia and restricts abduction)
- Lateral collateral ligament (connects femur to fibula and restricts adduction)
Intracapsular ligaments- Restricts movement between bones.
Cruciate ligaments of knee- arise from tibia and insert into femur.
1. anterior cruciate ligament (ACL)- anterior of tibia to posterior to femur, restricts posterior displacement of femur.
2. Posterior cruciate ligament (PCL)- posterior of tibia to anterior of femur, restricts anterior displacement of femur.
Meniscus
Is a pad of fibrocartilage between opposing bones within a synovial cavity, channel the flow of synovial fluid, or allow for variations in the shapes of the articular surface.
Fat Pads
Are localised masses of adipose tissue covered by a layer of synovial membrane. They are commonly superficial to the joint capsule. Fat pads protect articular cartilage and act as packing material for the joint. When the bones move, the fat pads fill in the spaces created as the joint cavity changes shape.
Bursa
Is a small, thin, fluid-filled pocket that forms in connective tissue outside joint capsule. It contains synovial fluid and is lined by synovial membrane. Bursae often form where tendon or ligament rubs against other tissues. Located around most synovial joints, including the knee joint, bursae reduce friction and act as shock absorbers.
What are fibrous joints?
Tissue- collagen
Limited movement/ stability.
Cartilaginous joints:
Some movement
tissue- fibrocartilage
Synovail joints
Free moving, most limb joints
Amount of and direction of movement is determined by joint structure.
What amount of movement is possible?
ROM- (range of movement)
bone end shape
Ligament location and length
Body surface contact.
