The Knee Joint - Bones, Joints, Muscles Flashcards
(34 cards)
There are 3 likely knee conditions that can occur from the strange articulations of the knee.
Genu Varum
Genu Valgum
Genu Recuratum
What happens to the femur with each condition?
Genu Varum (Bow legs) - Knees naturally outwards, femur rotated externally Genu Valgum (Knock-Knees) - Knee collapse inwardly, femur rotated internally Genu Recuratum (False Curvature) - Femur rotated internally, tibia rotated internally
What are the characteristics of FEMORAL medial and lateral condyles?
Medial Femoral Condyle: - Rounded in profile - Extends more distally (Longer) - Narrower Lateral Femoral Condyle: - Flattened in profile - Shorter distally (Shorter) - Wider surface
What are the characteristics of the medial and lateral TIBIAL condyles?
Medial Tibial Condyle: - Larger surface area - Oval in shape - Concave in all axes Lateral Tibial Condyle: - Smaller surface area - Rounded in shape - Concave in medial/lateral axis
How does the femur move on a fixed tibia?
Flexion
Posterior roll –> Anterior glide –> Lateral spin to unlock knee (The opposite in extension)
How does the tibia move on a fixed femur?
Flexion
Posterior roll –> Posterior glide –> Medial spin to unlock knee (The opposite in extension)
What are the functions of the medial and lateral menisci of the knee? What are the similarities and differences?
Similarities - Both menisci have an anterior and posterior horns (Most of the weight bearing), have attachment points for the transverse ligament on the anterior of the tibia.
Differences - The medial meniscus is attached to knee capsule for weight bearing (More prone to injury due to this), lateral is unattached and allows more movement.
What is unique about the ligaments of the knee?
They are intracapsular and extra-synovial, to prevent the ligament being excessively damaged.
What are attachments of the anterior and posterior cruciate ligaments? (ACL and PCL)
ACL - Originates on the anterior condylar area of the the tibia and moves superiorly and laterally to the lateral side for the intercondylar notch.
PCL - Originates on the posterior condylar area of the intercondylar notch and rises superiorly, anteriorly and medially to the medial side of the intercondylar notch
What is the intercondylar notch?
It is the area between the medial and lateral condyles of the tibia
What are the three bursas (folds of synovial fluid) in the knee joint?
- Suprapatellar
- Prepatellar
- Infrapatellar
What happens with the synovial membrane in extension of the knee?
- Due to the posterior of the knee being compressed, the fluid flows to the front of the knee towards to the patellar bursas.
- To give the synovial more surface area to move into, there’s a small muscle which pulls the capsule up the femur to reduce vulnerability of the capsule being damaged.
What is the muscle called which pulls the synovial capsule up the femur?
Articularis genus
What happens with the synovial membrane in flexion of the knee?
- Due to the the anterior part of the knee being compressed, the synovial fluid flows to the posterior to an area behind the femoral condyles called the popliteal bursa.
What 3 anterior aspects of the knee joint protects the joint capsule from being damaged?
- The quadricep complex allows synovial fluid movements; looser capsule.
- Patella bone and patellar tendon
- Lateral and medial retinaculum (contracts with quadriceps)
What is the function of the collateral ligaments?
The medial (thick) and lateral (thinner) collateral ligaments protect joint capsule as well as holding the joint together; prevents lateral gliding.
What are the insertions of the collateral ligaments?
Medial Collateral ligament:
- Originates on the medial condyle, travels distally to insert in the tibial tubercle.
Lateral Collateral ligament:
- Originates on the lateral condyle, travelling posteriorly and distally to insert to the head of the fibula.
What is the function of the popliteus muscle within the knee joint, and what are its insertions?
- The function of the popliteus muscle is to laterally rotate to the femur on the tibia; to ‘unlock’ the knee to allow flexion.
- It originates on the anterior aspect on the lateral femoral condyle on a tendon and passes posteriorly through the joint capsule and inserts to the posterior aspect of the tibia.
What are the posterior ‘ligaments’? (They’re more thickenings of the posterior aspect of the joint capsule)
Oblique popliteal ligament: Originates on the medial condyle of the tibia, and moves superiorly and laterally to insert, roughly, at the intercondylar line of the femur.
Arcuate popliteal ligament: Originates on the lateral condyle of the tibia, sweeps round the popliteus and inserts, roughly, at the intercondylar line of the femur.
What are the bony landmarks of the patella?
Anteriorly: - Base; most proximal and superior - Apex; most distal and where patella ligament arises Posteriorly: - Lateral facet; larger in surface area - Medial facet; smaller in surface area (Covered in hyaline cartilage)
What happens to the patella during flexion and extension?
Extension: The patella rises as far anteriorly as possible; slightly more anterior than its attachment to the tibial tuberosity.
Flexion: The patella is dragged to the inferior side of the femoral condyles.
What is the fibrous tissue connecting the tibia and fibula together?
Interosseous membrane
There are two tibiofibular joints, what type of joints are they and what are their functions?
- Proximal Tibiofibular joint is a plane (gliding joint) synovial joint and will glide superiorly and laterally.
- Distal Tibiofibular joint is a fibrous joint, specifically called Syndesmosis, which are two bones running parallel connected my the interosseous membrane; creates very limited movement.
What are the 5 significant quadricep muscles from most superficial to the deepest?
- Sartorius
- Rectus Femoris
- Vastus Lateralis
- Vastus Medialis
- Vastus Intermedius
What are the insertions of the vastus muscles?
- The Vastus Lateralis and Medialis both originate from the posterior aspect either side of the intertrochanteric line and distally around the patella to the tibial tuberosity; creating the retinaculum
- The vastus intermedius has a proximal attachment of the anterior shaft of the femur and distally attaches to the base of the patella and over the patella to the tibial tuberosity.
