THE KNEE JOINT
Largest and most
complex joint of the
body.
Three joints are fused
into one i.e.
1. Lateral femorotibial
2. Medial femorotibial
3. femoropatellar
Type: compound synovial joint
Two condylar joints between the condyles of femur &
tibia
Saddle joint between femur & patella.
Articular surfaces
Condyles of femur
Patella
Condyles of tibia
Ligaments
1. Fibrous capsule
2. Ligamentum patellae
3. Medial collateral(tibial)
4. Lateral collateral(fibular)
5. Oblique popliteal
6. Arcuate popliteal
7. Anterior cruciate
8. Posterior cruciate
9. Medial miniscus
10. Lateral miniscus
11. Transverse ligament
12. Meniscofemoral Ligaments
(Ligament of Wrisberg)
Ligaments
Extracapsular ligament
1. Ligamentum patellae
2. Lateral collateral ligament
3. Medial collateral ligament
4. Oblique popliteal ligament
The synovial membrane
1. Large and complicated
2. Attached to 3 bones: femur, tibia and fibula.
3. Below the patella, it is separated from the patellar
ligament by a mass of fat called infra patellar pad
of fat.
BURSAE AROUND THE KNEE JOINT
Many bursae are found around the knee:
Four ………in front
Three ……..posteromedially
Three ……..posterolaterally
Intracapsular ligament
1. Cruciate ligament
Posterior cruciate
ligament
Anterior cruciate
ligament
Menisci
1) Ligamentum patellae:7.5
cm long and 2.5 cm broad.
Attached :
Above: to the margins and
rough posterior surface of
the apex of patella.
Below: to the smooth
,upper part of the tibial
tuberosity.
2) Lateral (fibular)collateral
ligament: strong cord runs
from the lateral epicondyle
of femur to the head of
fibula.
5 cm long.
The tendon of popliteus
separates the lateral
collateral ligament from
lateral meniscus.
3)Medial(tibial)collateral Superfical part runs from
ligament: the medial epicondyle of
Long band of great the femur to the medial
strength. surface of tibia several
Superiorly:attached to the inches below the knee
medial epicondyle of femur, joint (behind the insertion
Inferiorly:divides into of sartorius,gracilis and
anterior(superficial) and semi tendenous).
posterior(deep) part.
The deep part form part of the capsule of the knee
joint.
The collateral ligaments are liable to injury in full
extension of the knee as they are tight only in this
position.
The medial ligament may be torn from violent
abduction strains
The lateral ligament may be torn from violent
adduction force.
4)Oblique popliteal ligament:
expansion from the tendon of the semimembranosus.
Passes from the medial condyle of the tibia upwards
and laterally to be attached to the lateral condyle of
femur.
It is strong ,prevents hyperextension.
Closely related to popliteal artery.
Cruciate ligaments
2 strong fibrous bands which connects the tibia with
the femur.
Forms a cross(X) arrangement with each other.
Named according to the attachment on tibia.
Structures inside the knee joint
Four structures:
Two cruciate ligaments –anterior &posterior
B. Two semi lunar cartilages or MENISCI-medial &lateral.
The anterior cruciate It is relaxed when the
ligament: knee is ‘flexed’.
Becomes tense during
attached to the anterior ‘extension’.
inter condylar area of the
tibia. Helps to prevent
It passes upwards, backwards hyperextension of knee.
and laterally from the
intercondylar area of the
tibia to the posterior part of *The ACL prevents the shin
the medial surface of the bone from sliding forward in
lateral condyle of femur.
relation to the thigh bone.
Posterior cruciate ligament:
strong ligament, attached to
the most posterior part of the
posterior intercondylar area
of the tibia.
Passes upwards, forwards
and medially from the
posterior intercondylar area
of the tibia to the anterior
part of the lateral surface of
the medial condyle of femur.
Relaxed in extension and becomes tense in flexion of
the knee
Helps to prevent dislocation of femur forwards.
*The PCL prevents the shin
bone from sliding backward in
relation to the thigh bone.
Cruciate ligaments may be torn in severe abduction or
adduction injuries.
The anterior cruciate ligament may be torn in violent
hyper-extension or in anterior dislocation of the tibia
on the femur.
The posterior cruciate ligament
may be torn in posterior
dislocation.
Complete tear of both anterior &
posterior cruciate ligaments
results in an unusual antero-
posterior movement of the knee.
menisci
Two C –shaped fibrocartilaginous discs
Lie on the upper surface of the corresponding
condyle of tibia.
Each miniscus has:
1. Two ends: attached to the tibia.
2. Two borders: outer ,thick, convex, fixed to the
fibrous capsule.
inner, thin, concave & free.
3. Two surfaces :upper
surface concave for
articulation with femur.
Lower surface is flat,
rests on the peripheral
two-thirds of the tibial
condyle.
The medial miniscus
C shaped
Much broader behind
than in front.
It’s anterior horn is
connected to the lateral
meniscus by a few fibers
called the transverse
ligament of the knee.
It’s ‘anterior’ horn is attached to the
most anterior part of the
intercondylar area .
It’s ‘posterior’ horn is attached
immediately in front of the
attachment of the posterior cruciate
ligament.
It is a ‘fixed’ cartilage –it’s outer border is firmly
adherent to the capsule of the knee joint, and
to the medial collateral ligament.
Function: to increase the concavity of the upper
surface of the medial condyle of tibia.
The lateral miniscus
Circular
Posterior end attached to the femur through two
miniscofemoral ligaments.
It is less fixed i.e. more mobile than the medial
cartilage
BURSAE AROUND
THE KNEE JOINT
Many bursae are found in the
knee.
Four -------in front
Three------posteromedially
Three------posterolaterally
The four bursae of anterior surface
Two subcutaneous bursae:
1. Prepatellar
2. Subcutaneous infra patellar
Two deep bursa:
1. Deep infrapatellar
2. suprapatellar
The subcutaneous prepatellar bursa: lies between the
skin and the lower part of the patella.
Knee Bursae
The subcutaneous and deep
infrapatellar bursa lie on the
superficial and deep aspects
of lower part of patellar
ligament
The subcutaneous bursa lies
between the patellar
ligament and the skin,
Deep bursa lies between the
patellar ligament and the
tibia.
The suprapatellar bursa: lies between the posterior
surface of the quadriceps tendon and the lower part
of the shaft of femur.
The 3 bursa on the posteromedial aspect
of knee.
1. Bursa deep to the medial
head of gastrocnemius.
2. Bursa between the
tendons of
sartorius,gracilis and
semitendinosus and the
medial ligament.
3. Semimembranosus bursa
(associated with the
tendon of this muscle.
The 3 bursa on the posterolateral aspect
of the knee.
1. Bursa deep to the lateral
head of gastrocemius.
2. A small bursa between
the biceps tendon and
the lateral ligament of
the knee,
3. The part of the synovial
membrane which is
related to the popliteus
tendon .
