The Knee Joint Flashcards
How many bones make up the knee joint?
3
Knee - Joint type
Hinge, synovial
Movements allowed by the knee joint
Flexion, extension, and a small degree of medial and lateral rotation
In the knee joints, the receptacles for the femoral condyles are…
Medial & lateral tibial condyles (medial & lateral tibial plateaus)
The patella is…
A sesamoid (floating) bone imbedded in quadriceps & patellar tendon
Function of the patella
It improves angle of pull, resulting in greater mechanical advantage in knee extension
The fibula is not part of the knee joint. True or false?
True
The medial and lateral tibial plateaus are smooth superior surfaces. True or false?
True
Articulations at the knee joint
Patellofemoral
Tibiofemoral
The articular surfaces of the femur, tibia and patella are covered with
hyaline cartilage
The joint capsule is attached to the ____ margins of the articular surfaces and surrounds the _____
margins of the articular surfaces; surrounds the sides and posterior aspect of the joint
Where is the joint capsule absent in the knee joint?
On the front of the joint
The suprapatellar bursa is formed…
In front where the capsule is absent, permitting the synovial membrane to pouch upwards beneath the quadriceps tendon
Posteriorly, the knee joint capsule is strengthened by:
an expansion of the semimembranosus muscle called the oblique popliteal ligament
On each side of the patella, the knee joint capsule is strengthened by…
…expansions from the tendons of vastus lateralis and medialis
The knee joint is relatively strong mechanincally. True or false?
False, it is weak
Stability of the knee joint depends on
- Strength and actions of the surrounding muscles and their tendons
- Ligaments connecting femur and tibia
The most important muscles for support here are the
Quadriceps femoris
Which muscles’ inferior fibres also aid stability here?
Vastus medialis and lateralis
The synovial membrane of the knee joint lines…
…the internal aspect of the fibrous capsule and attaches to the periphery of the patella and the edges of the menisci
The synovial membrane reflects from…
…the posterior aspect of the joint onto the cruciate ligaments
The knee joint cavity extends superior to the patella as the suprapatellar bursa. True or false?
True
The fibrous capsule is strengthened by extracapsular ligaments…
5:
Patellar ligament
Fibular collateral ligament (or LCL)
Tibial collateral ligament (or MCL)
Oblique popliteal ligament
Arcuate popliteal ligament
The LCL extends from…
…the lateral epicondyle of femur to lateral surface of head of fibula
The lateral meniscus is separated from the LCL by…
Tendon of popliteus
The tendon of biceps femoris is split into two parts by
lateral collateral ligament
The MCL extends from…
…the medial epicondyle of femur to medial condyle and superior part of medial surface of tibia
Where are the deep fibers of MCL firmly attached to the medial meniscus?
Its midpoint
Which is stronger - MCL or LCL?
LCL
Which is more prone to damage? MCL or LCL?
MCL
Which ligament strengthens the knee joint posteriorly?
Oblique popliteal ligament
The OPL extends from…
…the posterior medial tibial condyle and passes superolaterally to attach to the central part of the posterior aspect of the fibrous capsule
The arcuate popliteal ligament extends from
…the posterior aspect of fibular head and passes superomedially over tendon of popliteus and spreads over posterior surface of knee joint
Which knee ligament passes over the popliteus tendon?
Actuate popliteal
How many intracapsular ligaments are in the knee joint?
3:
Cruciate ligaments (anterior and posterior)
Menisci (medial and lateral)
Tendon of popliteus muscle
Are the cruciate ligaments located within the synovial membrane of the knee?
No, they’re within the capsule but outside the membrane
Which ligament is an expansion of the tendon of semimembranosus tendon in the knee joint?
OBL
The OBL rises…
…posterior to the medial tibial condyle and passes superolaterally to attach to the central part of the posterior aspect of the fibrous capsule
Which ligament strengthens the posterior part of the knee joint?
The OBL and Arcuate
Functions of the menisci of the knees
They deepen the articular surface of the tibia and act like shock absorbers
What are the menisci of the knees? Where are they found?
Crescenteric plates of fibrocartilage on the articulate surface of the tibia.
At what point is the menisci of the knee thicker?
It is thicker at the external margins and tapers to the unattached edge in the interior of the joint
The menisci are firmly attached to…
… the intercondylar area of the tibia
What are the ligaments of the menisci?
Coronary ligaments
Transverse ligaments
What is the function of the transverse ligaments of the knee?
It joins the anterior edges of the menisci and allows them move together during knee movements
What are the kinds of cruciate ligaments?
Anterior and Posterior
Properties of the anterior cruciate ligament
- Weaker, poor blood supply
- Slacks in flexion
Which cruciate ligament becomes taut during flexion?
The posterior cruciate ligament
Which ligament is the main stabilizing factor for the femur in walking downhill?
The posterior cruciate ligament
Function of the anterior cruciate ligament
It prevents posterior displacement of the femur on tibia and hyperextension
The posterior surface of the patella is covered with…
Thick hyaline cartilage
Functions of the patellofemoral joint
- increases angle of pull of quadriceps on tibia
- protects anterior portion of knee
- centralizes divergent tension of quadriceps into a single line of action
Which muscles are responsible for the flexion of the knee joint?
Hamstrings
Which muscles are responsible for the extension of the knee joint?
Quadriceps femoris
Which muscles are responsible for the lateral rotation of the knee joint?
Biceps femoris
Which muscles are responsible for the medial rotation of the knee joint?
Popliteus, Semitendinosus, Semimembranosus
The middle genicular branches of the popliteal artery penetrates the fibrous capsule of the knee joint and supplies the…
Cruciate ligaments
Synovial membrane
Peripheral margins of the menisci
The blood supply of the knee joint is from the…
Genicular branches of :
- Femoral
- Popliteal
- Anterior and posterior recurrent branches of the anterior tibial recurrent artery
- Anterior and posterior branches of circumflex fibular areteries
Innervation of the knee joint is by branches of the
Obturator
Femoral
Tibial
Common fibular nerves
How many bursae are around the knee joint?
About 10-12 bursae
What are the subcutaneous bursae?
Prepatellar and Infrapatellar bursae
Where are the subcutaneous bursae of the knee joint?
They are present at the convex surface of the joint so that the skin can move freely during movements of the knee
How many bursae communicate with the synovial cavity of the knee joint?
4:
suprapatellar
popliteus
anserine
gastrocnemius bursa
Which bursa is especially important because an infection of the bursa will spread to the knee cavity?
Suprapatellar
Genu varum and genu valgum result in…
… deviation of the tibia from the midline
Difference between Genu varum and Genu valgum
Genu varum- tibia diverted medially
Genu valgum- tibia diverted laterally
