Transcript 21-KNEE JOINT

KNEE JOINT
It is the largest 
and most
complicated joint in
the body.
FUNCTIONS
1. Weight bearing. 
2.Essential for daily 
activities: standing
walking & climbing
stairs.
3.The main joint 
responsible for sports:
running, jumping ,
kicking etc.
ARTICULATING BONES
1. Lateral and 
medial
articulations
between the tibial
condyles and their
cartilaginous
menisci and the
corresponding
femoral condyles.
ARTICULATING BONES
2. Intermediate
articulation
between the
patella and femur.

THE FEMORAL CONDYLES
The medial 
extends further
forwards .
The lateral is 
more oval.
The condyles are
convex from front
to back.

TIBIAL CONDYLES
(PLATEAUS) are flat . 
The medial is oval The 
lateral is round.
The articular surfaces 
are covered with
hyaline cartilage.

TYPE
A synovial joint of the
hinge variety
between the medial
and lateral condyles
of the femur and the
corresponding tibial
condyles with some
degree of rotation.

TYPE
A synovial joint of the
plane gliding variety
between the patella
and the patellar
surface of the femur.
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CAPSULE
It is absent Anteriorly. 
It is 
Replaced by : 
Quadriceps femoris 
tendon.
Patella. 
Ligamentum patellae. 
CAPSULE
Posteriorly : 
(a) Superior : 
Attached proximal to 
the articular margins
of the femoral
condyles and to the
intercondylar fossa.
It is deficient above 
the lateral condyle for
the passage of
tendon of popliteus.
CAPSULE
(b) Inferior : 
Attached to the 
tibia EXCEPT when
the tendon of
Popliteus crosses
the bone.
EXTRACAPSULAR LIGAMENTS
1. Ligamentum 
Patellae
It is the inter mediate
part of the tendon of
quadriceps femoris .It
is supported by the
patellar retinaculi
(expansions from the
vasti)
They strengthen the
capsule on each side.
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2. TIBIAL (MEDIAL)
COLLATERAL
A flat band. 
Attachment: 
Above to the medial 
condyle of the femur.
Below to the medial 
surface of the shaft of
the tibia.
Firmly attached to the
medial meniscus.

3. LATERAL (FIBULAR)
COLLATERA
Cord like. 
Attachment : 
Above : lateral condyle of
the femur.
Below : head of the 
fibula.
Separated from the 
lateral meniscus by the
tendon of popliteus.

4. OBLIQUE POPLITEAL
An expansion of 
the
Semimembranos
us.
It strengthens 
the capsule
posteriorly.
INTRA CAPSULAR
STRUCTURES
1. CRUCIATE
LIGAMENTS.
2. MENISCI. 
3. TENDON OF
POPLITEUS.


CRUCIATE LIGAMENTS
They are the main bond
between the femur and
tibia throughout the
joint’s movements.
They Cross each other 
within the joint cavity.
They are named 
Anterior and Posterior
according to their tibial
attachments.

ANTERIOR CRUCIATE
Tibial attachment : 
Anterior intercondylar 
area.
Course : 
Upward, backward and 
laterally.
Femoral attachment: 
Posterior part of medial 
surface of the lateral
condyle.
ANTERIOR CRUCIATE
FUNCTION 
Prevent posterior 
displacement of the
femur on the tibia
and the tibia from
being pulled
anteriorly when the
knee joint is flexed.
It is taught in 
hyper extension.
POSTERIOR CRUCIATE
Tibial attachment : 
posterior inter condylar
area.
Direction: 
upward, forward and 
medially.
Femoral attachment:
Anterior part of the 
lateral surface of the
medial condyle.

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POSTERIOR CRUCIATE
Function: 
prevents anterior
displacement of
the femur on the
tibia and the tibia
from being pulled
posteriorly when
the knee joint is
flexed.
It is taught in 
hyper flexion.

MENISCI
C shaped sheets of fibro
cartilage.
The peripheral border is
thick and attached to
the capsule.
The inner border is thin
and concave and forms
a free edge.

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
MENISC
The upper concave 
surfaces are in contact
with the femoral
condyles.
The lower flat 
surfaces are in contact
with the tibial condyles.
MENISCI
Functions : 
1. Deepen the 
tibial articular
surfaces.
2. Act as cushions
between the two
bones.

MEDIAL MENISCUS
Crescentic in 
shape.
More liable to 
injury due to its
attachment to the
medial collateral
ligament and to
the capsule.
It is relatively 
immobile.
LATERAL MENISCUS
More rounded in shape. 
Its anterior and posterior 
ends lie within the ends of
the medial meniscus.
Posteriorly it is separated 
from the fibular collateral
ligament by the tendon of
popliteus.
Less liable to injury. 
INJURY OF THE MENISCI
The menisci are frequently 
injured especially in
footballers and cricketers.
The medial is torn three 
times more often than the
lateral.
The injury is produced by 
the rotation of the femur
on the tibia or the reverse
with the knee joint
partially flexed and carries
the weight of the body.
INJURY OF THE MENISCI
The torn part of the 
meniscus is wedged
between the tibial and
femoral condyles.
No further movement 
is allowed and the joint
is kept locked.
SYNOVIAL MEMBRANE
It lines the lateral and 
medial parts of the
capsule.
Anteriorly : 
It forms the supra 
patellar bursa.
It is attached to the 
inter condylar area of the
tibia and to the lateral
and medial borders of
the patella.
SYNOVIAL MEMBRANE
It is reflected backward
from the posterior
surface of the
ligamentum patellae to
form the Infrapatellar
fold.
The free borders of the 
fold are the Alar folds.
The space between these
folds contains fat
(Infrapatellar pad of
fat).


SYNOVIAL MEMBRANE
Posteriorly : 
It Passes out to 
surround the cruciate
ligaments.
It is continuous with the 
surface layer of the
menisci.
It covers the tendon of 
popliteus and forms a
bursa around it
(popliteal bursa).
It forms the 
semimembranosus
bursa.
ANTERIOR BURSAE
They are four : 
1. Suprapatellar : 
It is 3 fingerbreadths above
the patella.
Always continuous with the
joint cavity.
Held in position by the 
articularis genus muscle.
Accumulation of fluid in the
joint causes excees fluid in
the bursa leading to floating
patella.
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ANTERIOR BURSAE
2. Prepatellar 
If enlarged it causes 
(House Maid’s) bursa.
ANTERIOR BURSAE
3.Superficial 
Infrapatellar.
(PARSON’S bursa
4.Deep 
Infrapatellar.
POSTERIOR BURSAE (6)
1. POPLITEAL 
Always continuous with 
the joint cavity.
2.SEMIMEMBRANOSU 
Usually communicates 
with the joint cavity.
3 & 4. 
GASTROCNEMIUS
Around sartorius,gracilis 
and semitendinosus.
MOVEMENTS
1. FLEXION 
Hamstrings( 
supplied by the
sciatic nerve).
Assisted by sartorius, 
popliteus and
gracilis.
Checked by back of •
calf in contact with the
back of the thigh.
MOVEMENTS
2. EXTENSION •
Quadriceps Femoris •
(supplied by the femoral
nerve.)
Limited by tension of the •
cruciate and collateral
ligaments.
MOVEMENTS
3. ROTATION •
(A) MEDIAL: •
Sartorius, gracilis and
semitendinosus.
(B) LATERAL : •
Biceps femoris
NERVE SUPPLY
Femoral. 
Obturator. 
Sciatic. 
Common peroneal.
Tibial. 

UNLOCKING
At the commencement of
Flexion of the extended
knee.
Aim : 
To slack the ligaments 
especially the cruciate.
FEMUR: Lateral rotation 
(the foot is on the ground)
TIBIA: Medial rotation. 
Muscle: POPLITEUS 

LOCKING
The joint assumes the 
position of full extension.
It becomes a rigid 
structure.
The menisci are 
compressed between the
tibial and femoral condyles.
Tightening of all the major
ligaments.
The femur is medially 
rotated on the tibia.

RELATIONS
Anterior : 
Prepatellar bursa.

RELATIONS
Posterior : 
Boundaries and 
contents of
Popliteal Fossa.
Medial : 
SGS muscles. 
Lateral : 
Biceps femoris and
common peroneal
nerve.

STABILITY
1. Muscles : 
QUADRICEPS 
particularly the inferior
fibers of the vasti
lateralis and medialis.
Many sport injuries 
can be preventable
through appropriate
training and
conditioning of the
muscle.
STABILITY
2. Ligaments : 
The knee joint can 
function well following
a ligamentous strain if
the quadriceps is
intact.
INJURY OF THE JOINT
TRIAD OF INJURY 
1. Medial collateral
ligament.
2. Medial meniscus.
3. Anterior cruciate
ligament.
The joint becomes 
swollen because it is
filled with blood
(hemarthrosis).



ANTERIOR CRUCIATE INJURY
Tear of the 
anterior cruciate
ligament is more
common than the
posterior.
The tibia can be 
pulled excessively
forward on the
femur
POSTERIOR CRUCIATE INJURY
The tibia can be 
pulled excessively
backward on the
femur.
INJURY OF THE CRUCIATE
LIGAMENTS
Management : 
Knee is kept 
immobilized in slight
flexion.
Active physiotherapy
of the quadriceps
femoris at once.
Operative repair 
(incase of torn of the
capsule and collateral
ligaments).

ANKLE JOINT
TYPE
Hinge synovial
ARTICULATING
BONES
1. Lower end of the
tibia
2. Two malleoli.
3. Body of the talus.
4. The inferior
transverse
tibiofibular ligament
deepens the socket
for the body of the
talus.
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ANKLE JOINT CONT’D
CAPSULE
Encloses the joint and
attached near the
articular margins except
anteriorly where
anteriorly it is attached
to the neck of the talus
in front of the articular
edge.
It is thin in front and
behind.
Posteriorly it fuses with
the inferior transverse
tibiofibular ligament.




SYNOVIAL MEMBRANE
Lines the capsule.
Reflected anteriorly
on to the neck of
the talus as far as
the articular
cartilage.
May extend a short
distance between
the tibia and fibula.



LIGAMENTS
MEDIAL( DELTOID)
Attached by its
apex to the tip of
the medial
malleolus.
Composed of deep
and superficial
fibers.
DEEP FIBERS
Attached to the
non articular area
on the medial
surface of the
body of the talus.
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LIGAMENTS CONT’D
Sustentaculum tali.
Plantar
calcaneonavicular
ligament.
Medial side of talus.
Tuberosity of
navicular bone.

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LATERAL LIGAMENT
Weaker than the
medial.
It consists of three
bands
1. ANTERIOR
TALOFIBULAR
Between the lateral
malleolus and the
lateral surface of the
talus.
2. CALCANEOFIBULAR
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3. POSTERIOR
TALOFIBULAR
Between the lateral
malleolus and the
posterior tubercle
of the talus.
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STABILITY OF THE JOINT
1. Shape of the articulating bones.
2. Strength of the ligaments.
3.The surrounding tendons.
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RELATIONS
MOVEMENTS
DORSIFLEXION
Tibialis anterior, extensors of the digits
and big toe, peroneus tertius.
LIMITED BY
Tension of tendo calcaneus.
Posterior fibers of the medial ligament.
Calcaneofibular ligament.
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PLANTAR FLEXION
Tibialis posterior, peroneus (longus and
brevis) gastrocnemius.
LIMITED BY
Tension of opposing muscles.
Anterior fibers of the medial ligament.
Anterior talofibular ligament.

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