What type of joint is the knee joint?
Hinge Type Synovial joint
What type of movements does the type of joint that the knee joint is allow?
Flexion and Extension (and to a degree, lateral and medial rotation)
Wat articultions is the knee joint formed by?
Articulations between the Patella, Femur and Tibia
What does the shape of the knee joint mean in relation to its strength?
What does it rely on to ensure stability?
Relies on muscles and ligaments
Label this diagram of a knee joint
Name the articulatons of the knee joint and describe what is articulating in each one
Tibiofemoral – The medial and lateral condyles of the femur articulating with the tibia
Patellofemoral – The anterior and distal part of the femur articulating with the patella
What articulation is the green highlighted area?
What articulation is the pink highlighted area?
Green - Tibiofemoral
Pink - Patellofemoral
What is the function of the tibiofemoral joint?
It is the weightbearing joint
What is the function of the patellofemoral joint and how does it do this?
Increases the efficiency of the quadriceps femoris muscle
Allows the tendon to be inserted directly over the knee
What are both joints lined by?
What are both joints enclosed by?
Both lined by hyaline cartilage
Both enclosed by a single joint cavity
In relation to the quadratus femoris tendon, what does the patella do?
Minimises wear and tear
Name the menisci of the knee joint
What type of structure are they?
Medial and Lateral
What are the functions of the menisci?
1 - To deepen the articular surface of the tibia, thus increasing stability of the joint
2 - To act as shock absorpers
What shape are the menisci and where do they attach?
Attach at both ends to the intercondylar area of the tibia
Where else does the medial menisci attach?
What clinical relevance does this have?
Also attaches to the tibial collateral ligament and the joint capsule
Any damage to the tibial collateral ligament results in tearing of the medial meniscus
What is the structure highighted in green?
What is the structure highighted in red?
What is the structure highighted in blue?
Green - Tibial Collateral Ligament
Red - Lateral Meniscus
Blue - Medial Meniscus
What is a bursa and what is it's function?
A bursa is synovial fluid filled sac, found between moving structures in a joint with the aim of reducing wear and tear on those structures
Name the bursae located in the knee joint and where they can be found
Suprapatella bursa – This is an extension of the synovial cavity of the knee, located between the quadriceps femoris and the femur
Prepatella bursa – Found between the apex of the patella and the skin
Infrapatella bursa – Split into deep and superficial. The deep bursa lies between the tibia and the patella liagment. The superficia lies between the patella ligament and the skin
Semimembranosus bursa – Located posteriorly in the knee joint, between the the semimembranosus muscle and the medial head of the gastrocnemius
Name the major ligaments in the knee
1 - Patellar Ligament
2 - Collateral Ligaments
2a - Tibial (medial) collateral ligament
2b - Fibular (lateral) collateral ligament
3 - Cruciate Ligaments
3a - Anterior cruciate ligament
3b - Posterior cruciate ligament
Where are the attachments of the patellar ligament?
A continuation of the quadriceps femoris tendon distal to the patella, it attaches to the tibial tuberosity
What are the shape of the collateral ligaments?
What is their function?
Stabilise the hinge motion of the knee and prevent any lateral or medial rotation
What shape is the Tibial (medial) collateral ligament?
Where are its attachments?
A wide and flat ligament
Proximally - Medial epicondyle of the femur
Distally - Medial surface of the tibia
What shape is the Fibular (lateral) collateral ligament?
Where are its attachments?
What is its function?
Thinner and rounder than the tibial collateral
Proximally - Intercondylar fossa of the femur
Distally - Posterior intercondylar region of the tibia
Prevents posterior dislocation of the tibia onto the femur
What are the four main movements of the knee joint?
What muscle(s) allow knee joint extension?
What muscle(s) allow knee joint flexion?
Hamstrings, gracilis, sartorius and popliteus
What muscle(s) allow knee joint Lateral Rotation?
What muscle(s) allow knee joint Medial Rotation?
Semimembranosus, Semitendinosus, Gracilis, Sartorius and Popliteus
How do injuries to the collateral ligaments occur?
Force being applied to the side of the knee when the foot is placed on the ground
How can damage to the collateral ligaments be assessed?
Asking the patient to medially rotate and laterally rotate the leg
Pain on medial rotation - Damage to the medial ligament
Pain on lateral - Damage to the lateral ligament
If the tibial collateral ligament is damaged, what else is more than likely torn?
The medial meniscus
How can damage to the anterior cruciate ligament (ACL) occur?
Hyperextension of the knee joint
Application of a large force the back of the knee with the joint partly flexed
How can you test for injury to the anterior cruciate ligament?
Peform an anterior drawer test where you attempt to pull the tibia forwards, if it moves, the ligament has been torn
What is the triad of injuries that damage to the anterior cruciate ligament displays known as?
What is the triad?
The Unhappy Triad
1 - Rupture of the medial collateral ligament
2 - Damage to the medial meniscus
3 - Rupture of the anterior cruciate ligament
What is the most common mechanism of posterior cruciate ligament damage?
What is it known as?
How else can it be damaged?
"Dashboard Injury" - This occurs when the knee is flexed and a large force is applied to the shins, pushing the tibia posteriorly. Often seen in car accidents
Can also be torn by hyperextension of the knee joint or damage to the upper part of the tibial tuberosity
How do you test for Posterior Cruciate Ligament damage?
How is it performed?
Posterior Drawer Test
Hold the knee in flexed position and pushed the shin posteriorly. If there is movement, the ligament has been torn
What can friction between the skin and the patella cause?
How does this clinically present?
Can cause the prepatella bursa to become inflammed
Produces a swelling on the anterior side of the knee known as housemaids knee
What can friction between the skin and tibia cause?
What is this known as?
Cause the infrapatella bursa to become inflamed