The document provides an overview of knee joint anatomy, describing the osseous structures (femur, tibia, patella), extra-articular structures (capsule, ligaments, muscles), and intra-articular structures (menisci, cruciate ligaments). It details the anatomy of the medial and lateral menisci, including their shape, composition, attachments, and functions in load bearing, stability, and joint lubrication. The cruciate ligaments and complex anatomy of the medial and lateral aspects of the knee are also summarized.

1. KNEE JOINT ANATOMY
-DR.JEMI

2. INTRODUCTION
The structures around the knee have been classified in to three
broad categories;
 OSSEUS STRUCTURE
 EXTRA ARTICULAR STRUCTURES
 INTRA ARTICULAR STRUCTURES

3. OSSEOUS STRUCTURE
It consist of three components : the patella, the distal femoral condyle, and
the proximal tibial plateaus or condyles.
The knee is called hinge variety of synovial type of joint.
THE DISTAL FEMORAL CONDYLE are two rounded prominances that are
eccentrically curved. Anteriorly, the condyles are some what flattened, which
creates a larger surface for contact and wt. transmission.
The groove found anteriorly between the condyles is the PATELLOFEMORAL
GROOVE OR TROCHLEA. Posteriorly the condyles are seprated by
intercondylar notch. The articular surface of the medial condyle is longer than
that of the lateral condyle but lateral condyle is wider.
Long axis of lareral condyle – along the sagittal plane, medial condyle at 22-
dgree angle to sagittal plane.

4. THE PROXIMAL END OF TIBIA forms two rather flat surfaces condyles or plateaus,
that articulate with the femoral condyles. Separated in midline by intercondylar
eminance with its medial and lateral intercondyler tubercles. Ant. & post. To
intercondyler eminance are the areas that serves as attachment sites for the
cruciate ligaments and menisci.

5. THE PATELLA – triangular sesamoid bone wider at proximal pole than distal pole.
The articular surface divided by vertical ridge – smaller medial and larger lateral
surface.
In extension, the distal portion of lateral articular patella facet articulate with the
lateral femoral condyle, but medial patellar facet barely articulates with the medial
femoral condyle untill complete flexion is approched. During flexion extension the
patella moves 7 to 8 cm in relation to the femoral condyle.

6. EXTRA ARTICULAR STRUCTURES
Consists of SYNOVIUM, CAPSULE, COLATERAL LIGAMENTS, AND
MUSCULOTENDINOUS UNIT PRINCIPALLY QUADRICEPS MECHANISM, THE
GASTROCNEMIUS AND MEDIAL AND LATERAL HAMSTRING GROUPS, THE
POPLITEUS, AND ILIOTIBIAL BAND.
QUADICEPS MECHANISM forms three layered quadriceps tendon that insert
on patella.
The tendon of rectus femoris – ant. Layer, inserts at the ant. Edge of proximal
pole.
The tendon of vastus intermedius – deepest layer, inserts at post. Edge of
proximal pole.
The vastus medialis and vastus lateralis – middle layer.
The fiber of medial retinaculum – formed from the aponeurosis of the vastus
medialis- inserts side of patella- prevent lat. Displcement.
Patella tendon – origin distal pole of the patella – inserts in to the tibial
tuberosity.

7. The gastrocnemius – the most powerful calf muscle, span post. Aspect of knee in
intimate relationship with post. Capsule, inserts on post. Aspect of , medial and
lateral femoral condyles.
Pes anserinus – conjoined insertion of the sartorius, gracilis, and semitendinousus
muscles along proximal medial aspect of tibia. Primary flexors of knee and
secondery intrenal rotational influence on tibia. protect knee- valgus and rotatory
stress.
The biceps femoris – counterpart of pes anserinus on lat. Side of knee insert into
fibular head, lateral tibia, and postlat.capsular structers. Provide varus and rotatory
stability.
The iliotibial band – post 3rd of ITB inserts proximally into the lateral epicondyle of
femur and distally into lateral tibial tubercle (gerdy tubercle)
Popliteus muscle- has three origin 1) lat. Femoral condyle 2) fibula{popliteofibular
ligament} 3) post. Horn of lateral meniscus.
Femoral and fibular origin – forms arm of oblique Y shaped ligament joined by
capsule and meniscal origin.
Prime medial rotator of tibia during flexion.

8. MEDIAL AND POSTEROMEDIAL CORNER OF THE KNEE
STABILISER
STATIC
- JOINT CAPSULE DYNAMIC
-SUPERFICIAL MCL -PES ANSERINUS
-DEEP MCL -SEMI MEMBRANOSUS
- POSTERIOR OBLIQUE LIG. -MEDIAL HEAD OF GASTROCNEMIUS
-VASTUS MEDIALIS
MARSHELL AND WARREN - THREE LAYERS OF MEDIALCAPSULER LIGA.STRUCTURE
LAYER-1:SUPERFICIAL FACIA LAYER-2:SUPERFICIAL MCL LAYER-3
THAT INVESTS SARTORIUS PARELLEL FIBERS AND OBLIQUE DEEP MCL - MENISCO
&QUDR. PROXIMLLY FIBERS. FEMORAL & MENIS-
WITH PES ANSERINUS & COTIBIAL PART.
PERIOSTEUM PROXIMALLY.

12. THE CAPSULE: IT IS SLEEVE OF FIBROUS TISSUE EXTENDING FROM THE PATELLA &
PATELLA TENDON ANT. TO MED, LAT, POST, EXPANSION OF JOINT.
CAPSULE AND MED & LAT EXTENSOR EXPANSION OF POWERFUL QUEDS. ARE
PRINCIPLE STABILIZING STRUCTURE ANT. TO TRNSVERSE AXIS OF JOINT.
THE CAPSULE IS REINFORSED BY COLLATERAL LIGA. , MED & LAT HAMSTRING
MUSCLE AS WELL AS BY POPLITEUS & ITB POST TO TRANSVERSE AXIS.
ANTMEDIALLY CAPSULE REINFORSE BY MED RETINACULUM EXPANSION, MPFL &
PATELLOTIBIAL LIGA.
ANTLATERALLY CAPSULE RENFORSE BY LAT EXPANSION OF RETINACULUM & ITB.
THE MCL – long narrow superficial to medial capsule & capsular ligamentous
structure, originating on the medial femoral epicondyle and inserting 7 to 10 cm
below the joint line on post. Half of med. Surface of the tibia metaphysis deep to
the pes anserinus tendon.
DEEP MCL: REINFORCE MIDMEDIAL CAPSULE , ORIGINATED FROM MED FEMORAL
EPICONDYLE AND INSERTED ON JUST BELOW THE TIBIAL ARTICULAR MARGIN.
-IT PROVIDES THE PRINCIPAL STABILITY TO VALGUS STRESSES.

13. ANTERIORLY – layer 2 &3 –discrete
POSTERIORLY – layer 2&3 merge to form posteromedial corner.
HUGHSTON AND EILERS described a discrete anatomic structure in the
posteromedial capsule called POSTERIOR OBLIQUE LIGAMENT (POL), a thickning of
the capsular liga. Attached proximally to adductor tubercle of femur and distally to
tibia and post aspect of the capsule.
POL THREE ARMS
TIBIAL ARM- ATTACHES SUPERIOR OR CAPSULAR SUPERFICIAL ARM-
CLOSE TO POST ARTICULAR ARM-WHICH IS CONTINUOS POORLY DEFINED
SURFACE OF TIBIA. WITH THE POST CAPSULE AND WHICH ATTACHES TO
BLEND WITH THE OBLIQUE SEMI M. TENDON AND
POPLITEAL LIGAMENT TIBIA.

15. SEMI MEMBRANOSUS FIVE EXTENSION IN TO POSTMEDIAL CORNER AND CAPSULE
1)PARS REFLEXA PASSING BENEATH MCL & INSERTING ON TIBIA
2)POSTMEDIAL TIBIAL INSERTION
3)THE OBLIQUE POPLITEAL LIGAMENT INSERTION
4)EXPANSION TO POL
5)POPLITEAL APONEUROSIS EXPANSION

16. KEY POINTS
SUPERFICIAL AND DEEP MCL ALONG WITH POSTMEDIAL STRUCTURE WORK IN
COORDINATION TO PROVIDE STABILITY- VALGUS AND EXT.ROTATION STRESS.
SUPERFICIAL LIGA. PRIMARY STABILISER AGAINST VALGUS & ER –THEN AFTER
DEEP MCL & POL.
QUDRICEPS MOST IMP FOR PROTECTION IN VALGUS STRESS.
KNEE FLEX –SEMI M. CONTRACTS TENSING THREE ARMS OF POL PROVIDING
BOTH KINETIC AND STATIC STABILISING EFFECT.
CONTACT SEMI M. TENSE TIBIAL ARM OF POLRETRECT POST. HORN OF
MED.MENISCI PREVENT IMPINGMENT OF MENISCUS AS THE KNEE FLEX.

17. LATERAL AND POSTERO LATERAL CORNER OF KNEE
ANATOMY IS COMPLEX AND VARIABLE.
A) ILIOTIBIAL BAND
- Extends proximally from its main distal insertion on Gerdy tubercle composed of four
main structures.
1)Main componant – superficial layer covers large portion of the lat. knee & is the 1st layer
encuntered after dissecting through the subcutaneous tissue of lateral knee
2)Iliopatellar band – ant. Expansion of superficial layer attach to lat. Border of patella & are
IMP IN PATELLOFEMORAL TRACKING.
3)Deep layer- attaches the medial aspect of superficial layer to distal aspect of lat. Inter
muscular septum.
4)capsulo-osseous layer- it begins proximally from region distal lateral intermuscular
septum & blends with confluence of facia from short head of biceps femoris & lateral
gastrocnemius tendon.
This capsulo-osseous layer and deep layer extends distally to attach to ant.lat. Aspect of
tibia just post & proximal to gerdy tubercle
CLINICAL SIGNIFICANCE – 2ND STABILISER OF LAT SIDE OF KNEE PX VARUS OPENING OF THE
KNEE

18. B) FIBULAR OR LATERAL COLLATERAL LIGAMENT
- primary static stabiliser to varus
- Proximal attachment site located in small bony depression slightly proximal &
postto lat. Femoral epicondyle. 1.4mm proximal & 3.1 mm post to lat femoral
epicondyle.
- Distally on to head of fibula at the apex of superior &lateral – facing V shaped
platue. An avg. 8.2mm post to ant. Aspect of fibular head & 28.4mm distal to
fibular styloid process.
- Avg. length 70mm

19. C) POPLITEUS MUSCLE – TENDON COMPLEX & POPLITEOFIBULAR LIGAMENT
- Provide both static & dynamic stability to postlat. Aspect of knee.
- Origin: broad muscle insertion at pos.med. Surface of proximal tibia metaphysis.
- Insertion: proximally main tendon attachment is at the proximal half ant 1/5th of
popliteus sulcus of femur about 18.5mm ant. & inferior to femoral insertion of
FCL.
- Three popliteomeniscal fecicles – ANT.INF, POST.SUP, POSTINF.
- Politeo fibular ligament- originates from popletius muscle-tendon complex.
- two division – ant. & post. Forms inverted Y . Ant. Division attaches to the down
slope of ant.med. Aspect of fibular styloid process. Post. Division attaches to the
apex and downslope of postmed. Fibular styloid process & provide more stability.

20. • -coronary ligament – distal to the musculotendinous junction of popliteous
muscle a broad aponeurotic attachment extend to attach to post.lat. Capsule &
post horn of lat. Meniscus, cinically- reinforce and stabilize the lat meniscus and
post. Knee capsule.
D) Long and short head of biceps femoris-
- two head of origin, long head tuberosity of ischium and sacrotuberous lig.
- Short head from lateral lip of the linea aspera between adductor magnus and
vastus lateralis.
- The tendon of insertion of this muscle forms the lateral hamstring & inserted
into lat. Side of head of fibula; the common peroneal nerve descend along its
medial border.
• - Both long and short head of biceps femoris prove static and dynamic
stability to lat and PLC of knee.
• E)Additional structure-
- Mid third lat capsular liga, is a thickning of lat capsule, two parts
• Menisco femoral menisco tibial
• extend from lat meniscus to lat meniscus to the tibia just post
anchorage just post to to gerdy’s tubercle
- Lat femoral epicondyle.

21. -Fabellofibular ligament – distal edge of capsule arm of short head of biceps
femoris , it inserts along the lat. Edge of fabella & attaches just lat to fibular
styloid.
-KEY POINTS :
-POST.LAT & LAT. STRUCTURES ACT IN COMBINATION WITH CRUCIATE
LIGAMENTS TO PROVIDE OVERALL STATIC & DYNAMIC STABILITY TO LAT. KNEE.
-THESE STRUCTURES FUNCTION PRIMARILY TO RESIST VARUS ROTATION & POST
LAT TIBIAL ROTATION, SECONDARY STABILISER TO ANT. POST. TIBIAL
TRANSLATION & IR STABILITY TO TIBIA.

23. INTRA ARTICULAR STRUCTURES
THE PRINCIPLE INTRAARTICULAR STRUCTURES ARE- MEDIAL AND LATERAL
MENISCI AND ANTERIOR AND POSTERIOR CRUCIATE LIGAMENTS.
MENISCI FUNCTION AND ANATOMY:
-FUNCTIONS:
-Act as a joint filler, compensating for gross incongruity between femoral and
tibial articular surfaces.
-They prevent capsular & synovial impingment during flexion and extension.
-Joint lubrication function
-Distribute synovial fluid through out the joint and aiding the nutrition of
articular cartilage.
-Provide stability in all plane but are especially imp. Rotatory stabilizer.
-Shock absorption
-Loadbearing or weight bearing function.

24. ANATOMY:
- The menisci are crescents ,roughly triangular in cross section that cover half to
one third of articular surface of tibia.
- They are composed of dense tightly woven collagen fibers arranged in a
circumferential and radial pattern providing great elasticity and ability to with
stand to compression.
- Peripheral edge- convex, attached to the inner surface of joint capsule except
where the popliteus is interposed laterally, also attached to the border of the
tibial plateau by coronary liga.
- Inner edge- concave, thin unattached.
- The menisci are largely avascular except near their peripheral attachment.
- Inferior surface is flat where as the sup. Surface is concave corresponding to
the femoral condyle.

25. Medial meniscus
-C shaped, larger diameter, thinner
periphery, narrower body, post horn
wider than ant.
-Ant horn- attach to tibia ant to inter
condylar eminance
-POST. Horn- attach in front of PCL post.
To the inter condylar eminance .
-Entire peripheral border is firmly
attached to medial capsule & coronary
ligament
-Does not attach either of cruciate liga.
Lateral meniscus
-More circular, more mobile than MM ,
smaller in DM , thicker periphery, wider
body.
-Ant horn – attached to tibia medially in
front of intercondyler eminance.
-Post horn – insert in to the post. Aspect
of intercondylar eminance in front of
post attacment of MM.
-Post horn receive anchorage to femur
by ligament of wrisberg and liga. Of
humphery & from facia covering the
popliteus , arcuate complex at post.lat.
Corner of knee.
-The tendon of the popliteus seprate the
post.lat. Periphery of lat meniscus from
joint capsule.

29. KEY POINTS:
- THE MENISCI FOLLOW THE TIBIAL CONDYLE DURING FLEX-EXT, BUT DURING ROTATION
THEY FOLLOW THE FEMUR MOVE ON TIBIA.
- ITS ANT AND POST ATTACHMENT FOLLOW THE TIBIA BUT ITS INTERVENING PART
FOLLOW THE FEMUR THUS ITS LIKELY TO BE INJURED DURING ROTATIONS.
- LATERAL MNISCUS FIRMLY ATTACHED TO THE LIGA. WRISBERG & HUMPHERY AND
POLITEOUS TENDON FOLLOWS THE LATERAL FEMORAL CONDYLE DURING ROTATIONS &
THEREFORE IS LESS LIKELY TO BE INJURED .
- ARNOCZKY AND WARREN SHOWED THAT THE VASCULAR SUPPLY TO M.M & L.M.
ORIGINATES PREDOMINANTLY FROM LAT. AND MED. GENICULAR VESSELS BOTH INF.
AND SUP.BRANCHES FROM THESE VESSELS GIVE RISE TO PERIMENISCAL CAPILLARY
COMPLEX THAT SUPPLIES THE PERIPHERAL BORDER OF MENISCUS.
- THREE ZONE OF MENISCAL VASCULARITY 1.RR- RED-RED IS FULLY WITHIN VASCULAR
AREA 2.RW, RED-WHITE ZONE IS AT BORDER OF VASCULAR AREA 3. WW, WHITE-WHITE
ZONE IS WITHIN AVASCULAR AREA.

30. ANTERIOR CRUCIATE LIGAMENT(ACL)
- ORIGINATES- from medial wall of lateral femoral condyle –course ant. & med.
Across the knee joint insert on tibial articular surface consist of anteromedial
& posterolateral bundle after their tibial insertion on on the tibial plataue ,
medial to the insertion of ant. Horn of L.M. ant.lat to the ant. Tibial spine.
- Primary role – provide stability against ant. Translation of tibia.
- Secondery role – rotatory stability
- Length – 31-35mm & 31.3mm2 in cross section.
- Pathology – composed of bundle of type-3 collagen fibril ensheathed by
connective tissue called enotendineum, together called subfacicular unit.this
unit surrounded by another layer of connective tissue called epitendineum
and whole unit called faciculus. Faciculus surrounded by pera tendon.
- Blood supply- middle genicular artery & inf med and lat. Genicular artery both
are branch of popliteal artery.
- Innervation- post. Articular nerve branch of tibial nerve.

32. POSTERIOR CRUCIATE LIGAMENT(PCL)
- Technically its extra articular structure.
- Synovium that reflect from post. Capsule surround ant. Med. Lat. Side
where as post. Border of PCL intimate with capsule and periosteum.
- ATTACHMENT
TIBIA FEMORAL
LAT TO MED ON TIBIA ADJUSCENT TO ANT. CARTILAGE
AT FOVEA ABUOT MARGIN OF MED FEMORAL
1-1.5 CM BELOW CONDYLE IN ANT-POST
JOINT LINE. DIRECTION.

34. PCL COMPONANT
ANTEROLTERAL BUNDLE POSTEROMEDIAL BUNDLE MENISCOFEMORAL LIGA.
Taut in flexion Taut in extension & deep
flexion
ANT. LIG. POST
OF HUMPHERY WRISBERG
BOTH ARISE FROM POST HORN
L.M. SANDWITCH PCL ANT& POST
AVG. LENGTH – 32-38 MM
CROSS SECTION AREA 31.2MM
BLOOD SUPPLY : MIDDLE & INF. GENICULAR ARTERY
INNERVATION : POSTERIOR ARTICULAR NERVE.
PROVIDE PRIMERY STABILITY TO POST. TRANSLATION OF TIBIA & ER.

35. SUMMERY:
VARUS STABILITY- PRIMARY BY LCL & SECONDARY BY PCL
VALGUS STABILITY- PRIMARY BY MCL & SECONDARY BY ACL
AGAINST ANT TIBIAL TRANSLATION – ACL
AGAINST POST TIBIAL TRANSLATION- PCL
IR – PRIMARY BY ACL SECONDARY BY PLC
ER- PRIMARY BY PCL SECONDARY BY PMC

36. POPLITEAL ARTERY:
- IS DEEPLY PLACED CONTINUATION OF FEMORAL ARTERY . IT COURSE THROUGH THE
POPLITEAL FOSSA AND ENDS AT LOWER BORDER OF THE POPLITEUS MUSCLE WHERE IT
TERMINATE IN TO ANT & POST TIBIAL ARTERY.
RELATIONS:
ANT: THE POPLITEAL SURFACE OF THE FEMUR, THE KNEE JOINT, POPLITEUS MUSCLE.
POST : POPLITEAL VEIN, TIBIAL NERVE, FASCIA AND SKIN.
POPLITEAL ARTERY
SUP GENICULAR ARTERY MIDDLE GEN. ART. INF. GENI ARTERY
MED .SUP LAT .SUP MED.INF LAT.INF
- MIDDLE GENICULAR ART. PROVIDE MAJOR BLOOD SUPPLY TO CRUCIATE LIG AND POST
CAPSULE & SYNOVIUM.
- MED.SUP.GEN. RUNS IN FRONT OF SEMI.M & SEMI.T ABOVE MED HEAD OF
GASTROCNEMIUS.

37. - LAT.SUP.GEN. - PASSES ABOVE THE LAT CONDYLE OF FEMUR BENETH THE TENDON OF
BICEPS FEMORIS.
- MED.INF.GEN.- FIRST DESCEND ALONG THE UPPER MARGIN OF POPLITEUS, THEN PASSES
BELOW THE MED TIBIAL CONDYLE BENEATH THE MCL, AT ANT BORDER OF WHICH IT
ASCEND IN FRONT AND MED SIDE TO SUPPLY KNEE JOINT & UPPER END OF TIBIA.
- LAT.INF.GEN. - RUNS LATERALWARDS ABOVE THE HEAD OF THE FIBULA TO THE FRONT OF
KNEE JOINT PASSING IN ITS CORSE BENEATH THE LAT. HEAD OF GASTROCNEMIUS FCL &
TENDON OF BICEPS FEMORIS.

38. THANK YOU