Joints Flashcards
What are the normal structural components of a synovial joint?
-Articular cartilage
-Synovial membrane
-Synovial fluid
-Synovium
-Tendon
-Ligament
-Fibrous joint capsule
What are the functions of the articular cartilage?
-Allow frictionless motion between joint surfaces
-Distrubution of joint load
-Dissipates energy associated with loading
-Aneural: Avascular: Alymphatic: Hypocellular
What is the function of tendons?
Join muscle to bone enabling movement
What is the function of ligaments?
Join bone to bone
Describe the articular cartilage
-Contain chondrocytes
-Low turn over
-Made of extracellular matrix (water, collagen, proteoglycans) chondrocytes synthesise these components and maintain this.
Describe the synovial membrane /lining
-Contains macrophages A cells (phagocytes) become activated when there is an inflamed joint = remove waste
-Contains fibroplasts B cells = produce hyaluronic acid
Where in a joint has or hasn’t got a vascular, lymphatic or nerve supply within it?
Every joint has a vascular and nerve supply, but there is no lymphatic supply in the cartilage of the joint
Define what is meant by cartilage homeostasis
Stable state and maintenance of the synovium and cartilage matrix in and out of the blood stream
What is meant by negative intra-articular pressure?
Pressure in the synovial fluid increases and decreases, a passive stabiliser so it is maintained.
What are the normal changes which occur at a joint with age?
-Joint movement becomes stiffer due to less synovial fluid and hyaluronic acid being formed to lubricate the articular cartilage
-Structure and thickness of the articular cartilage due to friction from loads and movement of ligaments and tendons (may shorten)
What are the bony landmarks found at the knee?
-Lateral Collateral
-Medial Collateral
-Posterior Cruciate
-Anterior Cruciate
What ligaments are found at the knee?
-LCL
-MCL
-ACL
-PCL
What is the function of the MCL ligament in the knee?
Prevents transverse movement pf the two bones (lateral or medial rotation)-Translation
Stops Varus (hinging forwards)
What is the function of the MCL ligament in the knee?
Stops opposite of the LCL
Stops valgus (hinging backwards)
What is the function of the ACL ligament in the knee?
Stops the tibia translating anteriorly to the femur
What is the function of the PCL ligament in the knee?
Stops the tibia translating posteriorly to the femur
What happens if ligaments tear?
Instability of the joint/ increases range of movement/ buckles/ possible dislocation if multiple tears/ swelling
What happens if ligaments thicken?
Stiffness/ lack of range of movement in certain directions depending on ligament
What happens if there is too much synovial fluid/ synovium?
Too lubricated/ Swelling/ Possible translation of joint/ pain
What happens if there is too little synovial fluid/ under active synovium?
Stiffness of joint/ more friction
What happens if the joint capsule is weakened?
Increased range of movement at the joint/ decreased stability
What happens if the joint capsule is thickened?
Decreased range of movement and stiffness/ increased stability/ lack of mobility in specific movement
What happens if the articular cartilage is reduced?
Increased friction/ rubbing + eroding of the distal and proximal bones meeting at joint/ swelling/ pain/ decreased range of movement
