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Knee Joint
Articular surfaces : It is a large and
complicated joint which includes 3
articulations :
1- between 2 condyles of femur / and
upper surfaces of 2 tibial condyles.
2- between the patella / and patellar
surface of femur.
Type :
1-between the condyles of femur & tibia:
is synovial hinge joint.
2-between the patella & femur :
is synovial joint of plane gliding type.
Capsule of Knee Joint
Anteriorly : it is absent,
replaced by pouching of synovial
membrane upward beneath the
quadriceps tendon, forming the
suprapatellar bursa.
On each side of patella : It is
Lateral view
strengthened by expansions from
tendons of vastus lateralis & medialis.
Posteriorly :
1- the capsule is strengthened by
expansion of semimembranosus ms.
called oblique popliteal ligament.
2- the capsule is pierced by popliteus
tendon opposite the back of lateral
condyle of tibia.
Ligaments of knee Joint
Extracapsular Ligaments :
1- Ligamentum patellae :
-above, it is attached to lower
border of patella./and below to
tibial tuberosity.
-it is a continuation of common
tendon of quadriceps femoris ms.
2- lateral collateral ligament :
-it is cordlike, attached above to
lateral condyle of femur./and below
to the head of fibula.
-this ligament is not firmly
adherent to the capsule.
-It is separated from lateral
meniscus by the tendon of
popliteus ms.
3-Medial collateral ligament :
-it is a flat band, attached
above to medial condyle of
femur./and below to medial
surface of shaft of tibia.
-it is firmly attached to medial
lemniscus.
4- Oblique popliteal ligament
-is a tendinous expansion of
semimembranosus ms.
-it strengthens the posterior
aspect of the capsule.
Ligaments of Knee Joint
Intracapsular ligaments :
1-anterior cruciate ligament :
Anterior veiw
-inferiorly : it is attached to the anterior
part of intercondylar area of tibia.
-superiorly : attached to posterior part of
medial surface of lateral condyle of femur.
-it prevents posterior displacement of
femur on tibia. With knee joint flexed, it
prevents tibia from being pulled anteriorly.
2-posterior cruciate ligament :
-inferiorly : it is attached to posterior part
of intercondylar area of tibia.
-superiorly : attached to anterior part of
lateral surface of medial condyle of femur.
-it prevents anterior displacement of
femur on tibia. With knee joint flexed, it
prevents tibia from being pulled posterioly.
Posterior veiw
3- Two menesci :
--are c-shaped sheets of fibrocartilage,
placed between condyles of femur & tibia.
--the peripheral border is thick and attached
to the capsule, while the inner border is thin
and concave and forms a free edge.
Upper end of tibia
--each meniscus is attached to upper
surface of tibia by anterior & posterior
horns.
--because the medial meniscus is also
attached to medial collateral ligament, it is
relatively immobile.
--Their function :
1- is to deepen the upper articular surfaces
of tibial condyles to receive the convex
femoral condyles.
2- they serve as cushions between the two
condyles.
Posterior aspect
Synovial Membrane
It lines the capsule and attached to the
articular margins.
On front and above the joint : it
forms a pouch extending up beneath
quadriceps femoris ms. for about 3
fingerbreadth above the patella, forming
suprapatellar bursa., which helds in
position by the attachement of a small
portion of vastus intermedius, called
articularis genu ms.
At the anterior part of the joint : it is
reflected from the back of ligamentum
patellae to form infrapatellar fold ,/ the
free borders of the fold is called, alar
folds. /It encloses infrapatellar pad of fat.
Synovial Membrane
At the back of the lateral meniscus : it
forms a pouch medial to popliteus tendon
and separates the tendon from lateral
meniscus & lateral femoral condyle.
At the back of medial meniscus :
-it forms the semimembranosus bursa
-it may communicate with synovial cavity
of the joint.
At the back of the capsule :
-It is reflected forward from the posterior
part of the capsule around the front of
cruciate ligaments, so cruciate ligaments
lie behind the synovial membrane and
not communicate with the synovial cavity
(extrasynovial).
Bursae of Knee Joint
They are found wherever skin,
ms. Or tendon rubs against bone.
4 are located in front of joint
(anterior) / and 6 behind the joint
(posterior).
Suprapatellar bursa + popliteal
bursa always communicate with the
joint. / semimembranosus bursa
may communicate with joint.
Bursae of Knee Joint
Anterior bursae :
1-suprapatellar bursa :
lies beneath quadriceps ms. And
communicates with joint cavity.
2-prepatellar bursa :
lies in subcutaneous tissue between skin
& front of lower part of patella + upper
part of ligamentum patellae.
3-superficial infrapatellar bursa :
lies in subcutaneous tissue between skin
and front of lower part of ligamentum
patellae.
4-deep infrapatellar bursa :
lies between back of ligamentum patellae
and tibia.
Bursae of Knee Joint
Posterior bursae :
1-popliteal bursa : lies in
association with the tendon of
popliteus and communicates with
the joint cavity.
2-semimembranosus bursa :
is found related to insertion of
semimembranosus ms. And may
communicate with joint cavity.
3- the remaining 4 bursae :
are found related to : tendon of
insertion of biceps + related to
tendons of insertion of sartorius,
gracilis, and semitendinosus
muscles, lying beneath lateral &
medial heads of gastrocnemius.
Relations and Nerve Supply
of Knee Joint Anteriorly : prepatellar bursa.
Posteriorly :
-popliteal vessels + L.Ns.
-tibial N. + common peroneal N.
-boundaries of popliteal fossa :
upward & medially :
semimembranosus & semitendinosus.
Upward & laterally :
biceps femoris.
Downward & medially : medial head of
gastrocnemius.
Downward & laterally : lateral head of
gastrocnemius.
N.supply :
1-femoral N.
2-Obturator N.
3-Common peroneal N. 4-Tibial N.
Medially : sartorius, gracilis, and
semitendinosus.
Laterally : biceps + common
peroneal N.
Movements of Knee joint
1- Extension :
-It is produced by : quadriceps femoris.
-It is accompanied by slight lateral rotation of tibia
(or medial rotation of femur), because the medial
condyle of femur is curved from before backwards,
while the lateral condyle is straight.
2- Flexion :
-by hamstring ms. : biceps, semitendinosus, and
semimembranosus.
-Assisted by : sartorius, gracilis, and popliteus.
3- Medial rotation : by sartorius, gracilis, and
semitendinosus.
4- Lateral rotation : by biceps femoris.
Meniscal injury of knee joint
 Injury of medial meniscus is
injury of medial meniscus on
more common than the lateral
playing football.
one, because of its strong
attachment to the medial
collateral ligament, which
restricts the mobility of medial
meniscus.
 The injury occurs when femur
is suddenly rotated medially
on tibia, with semiflexed knee
joint specially in foot-ball
players.
 The tibia is usually abducted
on femur and medial meniscus
is pulled into abnormal
Tearing of medial
meniscus of knee joint
position between femoral &
tibial condyles.
Complete bucket handle
tear
Tearing of posterior part
Tearing of peripheral part
Tearing of anterior part
Strength of Knee joint /and
injury of its ligaments :
 The strength and stability of the joint depends
largely on the strength of quadriceps femoris ms. +
integrity of the ligaments that bind femur to tibia.
 Medial collateral ligament injury :
-It is more common than the lateral one.
-Partial tearing of the ligament can result from
forced abduction of tibia on femur.
-Sprains of medial collateral lig. result in
tenderness over femoral or tibial attachments of
ligament.
 Lateral collateral ligament injury :
-it is less common than medial collateral lig.
-it can result from forced adduction of tibia on
femur.
Strength of Knee joint /and
injury of its ligaments :
 Cruciate ligaments injury :
B, test for integrity of
anterior cruciate ligament.
C, test for integrity of
posterior cruciate ligament.
-Tears of anterior cruciate ligament
are common than the posterior
cruciate ligament.
-it is accompanied by damage to
other structures : collateral
ligaments are commonly torn./ or
the joint cavity fills with blood
(hemarthrosis) and is swollen.
-In ruptured anterior cruciate lig.,
tibia can be pulled excessively
forward on the femur.
–In ruptured posterior cruciate lig.,
tibia can be moved excessively
backward on the femur.
Joints of Foot :
Subtalar (Talo-calcanean) Joint
Articulation :
:
1-inferior surface of body of
talus.
2-facet on middle of upper
surface of calcaneum.
Type : plane synovial joint.
Ligaments : medial, lateral
talo-calcaneal ligaments +
interosseous strong (talocalcaneal) ligament between
sulcus tali & sulcus calcanei.
Movements : Gliding and
rotatory.
Talo-calcaneonavicular Joint
Articulation :
1-rounded head of talus.
2-upper surface of
sustentaculum tali.
3-concave surface of navicular
bone.
Type : ball and socket
synovial.
Ligaments :
plantar calcaneo-navicular
ligament (Spring ligament) :
-strong, between sustentaculum
tali posteriorly & tuberosity of
navicular bone anteriorly.
Calcaneo-cuboid joint
Articulation :
1-anterior end of calcaneum.
2-posterior surface of cuboid.
Type : plane synovial.
Ligaments :
1-bifurcated ligament :
-strong y-shaped, lying on upper
surface of joint.
-stem : is attached to upper surface of
anterior part of calcaneum.
-lateral limb : attached to upper
surface of cuboid bone.
-medial limb : attached to upper
surface of navicular bone.
Lateral view
Calcaneo-cuboid joint
2-Long plantar ligament :
-strong ligament lying on the lower
surface of joint.
-between : undersurface of
calcaneum & undersurface of cuboid
+ bases of 2nd , 3rd and 4th metatarsal
bones.
-it bridges over the groove for
peroneus longus tendon, coverting it
into a tunnel.
3-short plantar ligament :
- strong ligament between
undersurface of calcaneum and
cuboid bones.
Movements in Subtalar,
Talo-calcaneonavicular, and
Calcaneo-cuboid Joints :
 Talo-calcaneonavicular + calcaneo-cuboid joints
are referred to as midtarsal or transverse tarsal
joints.
 Inversion + eversion of foot take place in subtalar +
transverse tarsal joints.
 Inversion is performed by : tibialis anterior, tibialis
posterior, extensor H.L + medial tendons of
extensor D.L.
 Eversion is performed by : peroneus longus,
peroneus brevis, and peroneus tertius. Lateral
tendons of extensor digitorum longus assist.
Femoral nerve injury (L2,3,4)
Causes : By stab or gunshot wounds,
but a complete division is rare.
Motor changes :
1-quadriceps femoris muscle is
paralyzed and knee cannot be
extended. In walking, This is
compansated for to some extend by the
action of adductor ms.
Sensory changes :
1- loss of skin sensation over
anterior & medial sides of thigh.
( intermediate + medial cutaneous N.
of the thigh injury).
2-loss of sensation over medial side
of leg + medial border of foot as far
as the ball of big toe.
(saphenous N. injury)
Sciatic nerve injury
(L4,5/S1,2,3) Causes :
1-penetrating wounds.
2-fractures of pelvis or dislocation of hip
joint.
3-wrong injections into gluteus maximus or
medius ( upper outer quadrant of the buttock
is the best site).
In 90% of cases, common peroneal part of
the sciatic N. is the most affected because its
fibres lie most superficial in sciatic N.
Motor changes :
1-paralysis of hamstring ms., but weak
flexion of knee is possible by the action of
sartorius (Femoral N.) + gracilis (obturator
N.).
2-paralysis of extensors of the leg, leading
to foot drop.
Sciatic nerve injury
Sensory changes :
(L4,5/S1,2,3)