Flashcards in Knee Joint Deck (45):
Which actions does the knee joint allow for?
flexion & extension
(v small amounts of medial & lateral rotation)
What are the articulations within the knee joint?
patella, femur, tibia
What does the shape of the knee joint suggest?
it is weak and relies on muscles and ligaments to ensure stability
Which muscles have a common distal attachment to the base of the patella?
quadriceps femoris (anterior thigh muscles)
How many articulations are there in the knee and what are they?
tibiofemoral and patellofemoral
(tibia with femur) and patella with femur
Describe the tibiofemoral articulating surface
medial and lateral condyles of femur articulate with tibia
Describe the patellofemoral articulation
anterior and distal part of femur articulate with patella
What is the main function of the tibiofemoral joint?
weightbearing joint of the knee
What does the patellofemoral joint allow?
the tendon of the quadriceps femoris (anterior thigh - extensors at knee) to insert directly over the knee
increases the efficiency of the muscle
both joint surfaces lined with hyaline cartilage & enclosed within single joint cavity
Where is the patella formed? how is this beneficial?
inside the tendon of quadriceps femoris
minimises wear & tear on the tendon
What are the functions of the lateral and medial menisci? What type of structures are they?
1. deepen the articular surface of the tibia - increasing stability
2. shock absorbers
What shape are the menisci and where do they attach?
attached at both ends to the intercondylar area (between 2 condyles) of the tibia
Where else is the medial meniscus attached to apart from the intercondylar attachment? what does this result in?
attached to the tibial collateral ligament and the joint capsule
any damage to the tibial collateral ligament results in tearing of the medial meniscus
Why is the lateral ligament fairly mobile?
only attaches to the intercondylar eminence of the tibia
What is a bursae?
a synovial fluid filled sac found between moving structures of a joint to reduce wear and tear on the structures of the joint
How many bursae are there in the knee joint and what are they?
1. suprapatella bursae
2. prepatella bursa
3. infrapetella bursa
3. semimembranosus bursa
Describe the suprapatella bursa
extension of the synovial cavity of the knee, located between the quadriceps femoris and the femur
(prevent quadriceps femoris from rubbing on the femur)
Describe the prepatella bursa
between apex of patella and skin
Where is the infrapatella bursa?
split into deep and subcutaneous (superficial)
deep bursa lies between tibia & patella ligament
subcutaneous bursa lies between patella ligament and skin
Where is the semimembranosus bursa?
located posteriorly in the knee joint
between semimembranosus muscle (deep medial posterior thigh) and the medial head of the gastrocnemius (posterior leg)
What are the major ligaments of the knee joint?
1. patellar ligament
2. collateral ligament
3. cruciate ligament
What and where is the patella ligament? Where does it attach to?
a continuation of the quadriceps femoris tendon distal (beneath) to the patella
attaches to the tibial tuberosity (anterior superior tibia)
What are the collateral ligaments' function?
2 trap-like ligaments either side of the knee joint
stabilise the hinge motion of the knee (extend and flex), preventing any medial or lateral movements
Where is the tibial (medial) collateral ligament found? attachments?
a wide and flat ligament, found on medial side of the joint
proximally: attaches to medial epicondyle of femur
distally: medial surface of tibia
Where is the fibular (lateral) collateral ligament found? attachments?
thinner & rounder than the tibial collateral ligament
attaches proximally to the lateral epicondyle of the femur
distal: attach to depression on the lateral surface of the FIBULAR HEAD
What are the cruciate ligaments?
2 ligaments connecting the femur to the tibia
cross over each other - hence 'cruciate'
Where is the anterior cruciate ligament found? attachments? function?
posterior intercondylar fossa of femur to the anterior intercondylar region of the tibia
prevents anterior dislocation of tibia in relation to the femur
Where is the posterior cruciate ligament found? attachments? function?
anterior intercondylar fossa of femur to posterior intercondylar region of tibia
prevents posterior dislocation of the tibia onto the femur
What are the movements of the knee joint?
3. lateral rotation
4. medial rotation
Which muscles carry out the extension of the knee?
quadriceps femoris - inserts into tibial tuberosity via the patella
Which muscles carry out the flexion of the knee?
hamstrings: semimembranosus, semitendinosus, biceps femoris
popliteus, sartorius, gracilis (all cross the knee joint)
Which muscles carry out the lateral rotation of the knee?
Which muscles carry out the medial rotation of the knee?
semimembranosus, semitendinosus, gracilis, sartorius, popliteus
When cn lateral and medial rotation occur?
when the knee is flexed - otherwise only occurs at the hip joint
What type of joint is the knee joint?
bicondylar type synovial joint
Clinical: injury to the collateral ligaments
what causes injury to the collateral ligaments?
caused by force being applied to the side of the knee when the foot is placed on the ground
How can damage to the collateral ligament be assessed?
by asking the patient to medially rotate and laterally rotate the leg (flexed at knee)
pain on medial rotation = damage to medial (tibial) collateral ligament
pain on lateral rotation = damage to lateral (fibular) collateral ligament
What is likely to be damaged if the tibial (medial) collateral ligament is damaged?
medial meniscus - as the medial meniscus is attached to the tibial collateral ligament
how can the anterior cruciate ligament be torn?
1. hyperextension of the knee joint
2. application of a large force to the back of the knee with the joint partly flexed
How do you test for anterior cruciate ligament (ACL) damage?
perform an anterior drawer test
attempt to pull the tibia forwards - if it moves then the ligament has been torn
What is the most common way to damage the posterior cruciate ligament (PCL)?
1. 'dashboard' injury
when knee is flexed and a large force is applied to the shins - pushing the tibia posteriorly
seen in car accidents when knee hits dashboard
2. hyperextension of the knee joint
3. damage to the upper part of tibial tuberosity (insertion of quadriceps femoris - used for extension)
How do you test for posterior collateral ligament damage?
perform posterior draw test
clinician holds the knee in flexed position, and pushes the shin POSTeriorly
if there is movement then the PCL has been damaged
What can cause inflammation of the prepatella bursae?
friction between the skin and the patella - cause prepatella bursa to become inflamed - producing swelling on anterior side of knee
What can cause inflammation of the (subcutaneous) infrapatella bursa?
friction between the skin and tibia