Download Knee joint

Knee
joint

The Knee Joint
Knee joint: 

1- the largest joint in 
body
2- the most complex one 
{allow mobility
(flexion/extension),
stability(weight bearing
joint) }
3-The most injured one 
actually 2 joints 
within the
articular capsule
1- tibio-femoral 
2-patello-femoral 
type and variety of the
knee joint
tibio-femoral joint 
•
(the articulation between the
femur and tibia, which is
weightbearing)
Type : •
synovial joint
•
Varity :
modified hinge joint (flexion 
and extension is primary
motion , Some lateral and
is possible (
medial rotation
when the knee is flexed

patello-femoral joint (the •
articulation between the patella and the
femur)
Type :
it
is saddle joint (the patella slides within the
patello-femoral groove)

•
Articulating Bones
Femur 

Tibia 
Patella 
Not part of the knee joint: 
fibula - it does not 
articulate with the femur
or the patella
Articular surfaces

covered by hyaline cartilage 
The major surfaces are : 
Lower end femur (medial and lateral femoral 
condyles )
upper end tibia (medial and lateral tibial condyles ) 
posterior aspect of the patella 

Enlarged femoral 
condyles articulate on
enlarged tibial condyles
on the anterior surface of 
the of the femur the two
condyles join to form Vshaped articular surfaces
between the femur and
posterior aspect of the
patella
Joint capsule
External fibrous layer 

(fibrous capsule)
Internal synovial 
membrane

The fibrous capsule capsule is extensive and thin
,However it has a few thickend part that make up the
intrinsic ligaments
Incomplete in some areas
reinforced by extensions from tendons of the
surrounding muscles
encloses the articular cavity and the intercondylar
region

superiorly Attaches to the femur , proximaly to 
articular margins of the condyles
Inferiorly Attaches to tibia , superior articular surface 
(tibial plateau)

1- anteriorly: It is absent 
and replaced by quadriceps
tendon, patella, and
ligamentum patellae, vastus
lateralis and vastus
medialis tendinons which
merge above with the
quadriceps femoris tendon
and below with the patellar
ligament , fibrous layer is
continuous with the lateral
and medial margins of
these structures.

2- medially: blends with 
the tibial collateral
ligament and is attached
to the medial meniscus
restricting its mobility

4-Laterally: the fibular 
collateral ligament which
separated from joint
capsule by fibular bursa ,
the internal surface of the
fibrous membrane is not
attached to the lateral
meniscus.

3-Posteriorly:enclose the 
condyles and the
intercondylar fossa and
has an opening for
popliteus tendon to pass
out the joint capsule and
attach to the tibia

anterolaterally: reinforced by from the iliotibial tract
Posteromedially : reinforced by oblique popliteal
ligament which is an extension from the
semimembranosus tendon
Synovial
membrane
Lines the fibrous capsule medially and
laterally and attaches to the margins
of the

articular surfaces(fermoral and tibial
condyles) ,outer margins of the menisci and
the posterior surface of patella ,reflects
anteriorly into the intercondylar region to
cover the cruciate ligaments excluding them
from the articular cavity , but they are
enclosed within the fibrous membrane
Anteriorly, the synovial membrane is
separated from the patellar ligament by an
infrapatellar fat pad also
Bursae
more than 10 bursae in & around knee 
bursa communicating with the 

articular cavity
suprapatellar bursa: a large bursa that 
is a continuation of the articular cavity
,superior to patella between the distal
end of the shaft of femur and the
quadriceps femoris muscle
subpopliteal recess: extends 
posterolaterally from the articular
cavity and lies between the lateral
meniscus and the tendon of the
popliteus muscle

bursae that are not communicating with the articular 
cavity
subcutanous prepatellar bursa: over the knee cap 
Deep infra-patellar bursae:underneath the patellar 
ligament
Subcutaneous or superfacial infra-patellar bursae: 
over the patellar ligament
Cruciate ligaments
Cruciate ligaments(L.crux,a 

cross): anterior and
posterior cruciate ligament
that crisscross within the
joint capsule in the
inercondylar fossa and
outside synovial cavity


anterior cruciate ligament(ACL): weaker 
than posterior one,attaches laterally in the
inercodyar fossa to the medial side of
lateral femoral condyle descend medialy
to to the anteroir intercondylar area of the
tibia just posterior to attachement of
medial meniscus
ACL limits the sliding of tibia too far 
forward (thus prevent the hyperextension
of knee )and femoral condyles too far
backward


posterior cruciate ligament: stronger 
than the anteroir one, attaches medially
in the inercodyar fossa to the lateral side
of medial femoral condyle descend
laterally to to the posterior intercondylar
area of the tibia
PCL limits the sliding of tibia too far 
backward(thus prevent the hyperflexion
of knee )and femoral condyles too far
forward