Download KNEE JOINT

KNEE JOINT
LEARNING OBJECTIVES
CLASSIFICATION
• Formed between lower end of femur, the upper end of tibia and the posterior surface of
patella.
• Gliding Synovial: Between anterior surface of lower end of femur and posterior
surface of patella
• Hinge synovial joint: Between inferior surface of condyles of femur and superior
surface of condyles of tibia is
ARTICULAR SURFACES
• BONES: the femur, tibia, and patella.
• ARTICULAR SURFACES: The condyles of the femur AND tibia, and the facets of the patella.
• Corresponding tibial and femur condyles articulate
• Articular surfaces of tibia are called medial and lateral tibial plateau
• Separated from each other by a narrow, nonarticular area, widened as anterior and posterior
intercondylar areas
LIGAMENTS
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Fibrous capsule
Ligamentum patellae
Tibial/ medial colletral ligament
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Fibular/ Lateral collateral ligament
Oblique popliteal ligament
Arcuate popliteal ligament
Anterior cruciate ligament
Posterior cruciate ligament
Medial meniscus
Lateral meniscus
Transverse ligament
ARTICULAR (fibrous) CAPSULE
• Strong, local thickenings form ligaments.
• Superiorly: Attached to the femur, just proximal to the articular margins of the
condyles
• Inferiorly: Attached to the articular margin of the tibia.
• Posteriorly: Attached to the Intercondylar line
• Laterally: Deficient on the lateral condyle, allowing the tendon of the popliteus muscle
to pass
• Inferolaterally: prolonged over the popliteus to form the arcuate popliteal ligament
ARTICULAR CAPSULE
Strengthened by five intrinsic ligaments;
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Patellar ligament
Fibular collateral ligament
Tibial collateral ligament
Oblique popliteal ligament
Arcuate popliteal ligament
SYNOVIAL MEMBRANE
• Largest and most extensive in the body.
• Commences at the upper border of the patella
• Forms a large cul-de-sac beneath the Quadriceps femoris in front of the lower end of
femur
• Communicates with a bursa interposed between the tendon and the front of the femur.
• The pouch is supported, during the movements of the knee, by the Articularis genu
PATELLAR LIGAMENT
• Continuation of the tendon of the quadriceps femoris muscle.
• The patella is a sesamoid bone in this tendon.
• Patella is most easily felt when the leg is extended.
• The infrapatellar fatpad:
– seperates the superior part of the deep surface of patella from the synovial membrane of the knee
joint.
• The deep infrapatellar bursa:
– separates the inferior part of the patellar ligament from the anterior surface of the tibia.
TIBIAL COLLATERAL LIGAMENT (medial ligament)
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A thickening of the fibrous capsule of the knee joint
8-9 cm long
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Origin:
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Insertion:
– medial epicondyle of the femur
– medial condyle and superio-medial surface of the tibia
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Partly continuous with the tendon of the adductor magnus muscle.
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The deep fibers are firmly attached to the medial meniscus and the fibrous capsule of the knee.
FIBULAR COLLATERAL LIGAMENT
• Round cord of 5cm
• Origin:
– lateral epicondyle of the femur
• Insertion:
– lateral surface of the head of the fibula.
• The tendon of the popliteus muscle passes deep to the fibular collateral ligament
• Separates it from the lateral meniscus.
OBLIQUE POPLITEAL LIGAMENT
• An expansion of the tendon of the semimembranosus muscle.
• Strengthens the fibrous capsule of the knee joint posteriorly.
• Origin:
– Posterior to the medial epicondyle of the tibia
• Insertion:
– passes superolaterally and attaches to the posterior aspect of the fibrous capsule of the knee joint
ARCUATE POPLITEAL LIGAMENT
• Y-shaped
• Strengthens the fibrous capsule Posteriorly.
• Origin:
– The stem arises from the posterior aspect of the head of the fibula.
– Passes superomedially over the tendon of the popliteus muscle, and spreads out over the posterior
surface of the knee joint.
• Insertion:
– Into the intercondylar area of the tibia and the posterior aspect of the lateral epicondyle of the femur.
CRUCIATE LIGAMENTS
• X shaped (cruciate).
• Anterior and Posterior, according to their site of attachment to the tibia.
• They are essential for the anteroposterior stability of the knee joint, especially when
it is flexed
• Within the capsule of the joint but are outside the synovial cavity.
CRUCIATE LIGAMENTS
• Join the femur and tibia
• Located between the medial and lateral condyles
• Separated from the joint cavity by the synovial membrane.
• The synovial capsule lines the fibrous capsule.
• Deficient posteriorly where it is reflected anteriorly around the cruciate
ligaments.
ANTERIOR CRUCIATE LIGAMENT
• Weaker
• Origin:
– From the anterior part of the intercondylar area of the tibia, posterior to the medial
meniscus.
• It extends superiorly, posteriorly, and laterally
• Insertion:
– attach to the posterior part of the medial side of the lateral condyle of the femur.
• Position of anterior cruciate ligament:
– Knee flexed: slack
– Knee extended: taut
• Prevents POSTERIOR DISPLACEMENT of the femur on the tibia on
hyperextension of the knee joint.
• Prevents ANTERIOR DISPLACEMENT of tibia when the joint is flexed at
a right angle
POSTERIOR CRUCIATE LIGAMENT
• Stronger
• First structure observed when the knee joint is surgically opened posteriorly.
• Origin:
– From the posterior part of the intercondylar area of the tibia
– passes superiorly and anteriorly on the medial side of the anterior cruciate ligament
• Insertion:
– attach to the anterior part of the lateral surface of the medial condyle of the femur.
POSTERIOR CRUCIATE LIGAMENT
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Tightens during flexion of the knee joint
Prevents ANTERIOR DISPLACEMENT of the femur on the tibia
And prevents POSTERIOR DISPLACEMENT of the tibia.
Prevents hyperflexion of the knee joint.
In the weight bearing flexed knee, it is the main stabilizing factor for the femur, e.g.,
when walking downhill or downstairs.
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Lateral and medial (G. crescents)
Slightly movable
Fill the gaps between the femur and tibia during movements of the knee joint
Act as shock absorbers.
C-shaped (semilunar cartilages)
Wedge-shaped in the transverse section.
Firmly attached at their ends to the intercondylar area of the tibia.
Present on the articular surface of the tibia and deepen it
Articulate with the femoral condyles.
MENISCI OF KNEE JOINT
MENISCI OF KNEE JOINT
SURFACES:
• Superior surfaces are slightly concave for reception of condyles
• Inferior surfaces that rest on the tibial condyles are flatter.
MARGINS:
• Thick at peripheral attached margins
• Thin at internal unattached edges.
MENISCI
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The capsular fibers that attach the thick, convex margins of the menisci to the tibial condyles are called
coronary ligaments.
A slender fibrous band, called the transverse ligament of the knee, joins the anterior edges of the two
menisci.
This connection allows them to move together during movements of the femur on the tibia.
The thick peripheral margins of the menisci are vascularised by genicular branches of the popliteal
artery
The unattached edges of the interior of the joint are avascular.
MEDIAL MENISCUS
• Cartilage is broader posteriorly than anteriorly.
• Firmly attached to the deep surface of the tibial collateral ligament.
The Anterior horn (L. cornu):
• Attached ANTERIOR to the attachment of the anterior cruciate ligament at the anterior
intercondylar area.
The posterior horn:
• Attached ANTERIOR to the attachment of the posterior cruciate ligament, at the to the
posterior intercondylar area.
LATERAL MENISCUS
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Nearly circular and conforms to the lateral tibial condyle.
Smaller
More freely movable
Covers a larger articular area than the medial meniscus
The tendon of the popliteus muscle and bursa separate it from the fibular
collateral ligaments.
• The anterior and posterior horns are attached close together in the anterior and
posterior intercondylar areas.
• A strong tendinous slip, called the posterior meniscofemoral ligament, joins the
lateral meniscus to the posterior cruciate ligament and the medial femoral condyle.
BURSAE COMMUNICATING KNEE JOINT
• Bursae reduce friction during movement between the bones and tendons
• Four bursa communicate with the synovial cavity of the knee joint:
– deep to the tendons of the quadriceps femoris
– the popliteus
– the medial head of the gastrocnemius muscle.
BURSAE AROUND KNEE
SUPRAPATELLAR (QUADRICEPS) BURSA
• Large saccular extension of the synovial capsule
• Passes superiorly between the femur and the tendon of the quadriceps femoris
muscle.
• Allows free movement of the quadriceps tendon over the distal end of the femur
• Facilitates full extension and flexion of the knee joint.
• The bursa is held in position by the part of the vastus intermedius muscle called the
articularis genu muscle.
PREPATELLAR BURSA
• Between the skin and the anterior surface of the patella.
• Allows free movement of the skin over the patella during flexion and extension of the
leg.
• May become inflamed after prolonged periods of weight bearing on the hands and
knees.
• Inflammation of this is "housemaid's knee"
SUBCUTANEOUS INFRAPATELLAR BURSA
• Located between the skin and the tibial tuberosity.
• Allows the skin to glide over the tibial tuberosity and withstand pressure when
kneeling with the trunk upright (e.g., when one kneels or genuflects during praying).
• Inflammation of this bursa is "clergyman's knee"
BLOOD SUPPLY
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Supplied by the anastomoses around it:
Five genicular branches of the popliteal artery
Descending genicular branch of the femoral artery
Descending branch of the lateral circumflex femoral artery
Two recurrent branches of the anterior tibial artery
Circumflex fibular branch of the posterior tibial artery
NERVE SUPPLY
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Femoral nerve, through its branches to the vasti.
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Sciatic nerve, through its genicular branches of the tibial and common
peroneal nerves.
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Obturator nerve, through its posterior division.