The document provides a comprehensive anatomical overview of the knee joint, detailing its structure, ligaments, and associated musculature. It highlights key components such as the anterior and posterior cruciate ligaments, menisci, and the vastus medialis and lateralis muscles, along with their roles in knee stability and movement. Special attention is given to the mechanics of knee flexion/extension and the impact of effusion on muscle function within the joint.

1. Complete Anatomical Detail
Of Knee Joint
By- Dr. Armaan Singh

2.  Synovial condylar
joint
 Close pack
 Full extension
 Least pack
 15 degree flexion

4.  The articular surfaces are the
medial and lateral femoral
condyles (the intercondylar
notch in between)
 The medial condyle has a
longer articular surface
 The superior aspect of the
medial and lateral tibial
condyles
 The posterior aspect of the
patella

5.  Average is 17 mm
 Narrow notch more likely to
tear ACL

7.  Sesamoid bone
 Thickest articular cartilage
in body
 Smaller medial facet
 Q-angle
 Controlled by Vastus
Medialis Obliquus (VMO)
and Vastus Lateralis
Obliquus (VLO)

8.  The patella is controlled by the oblique
portions of the vastus medialis and vastus
lateralis.
 The vastus medialis wastes within 24 hours
after an effusion of the knee
 If the oblique fibers of the vastus medialis
are wasted, the patella tends
to sublux laterally on extension
of the knee. This results in
retropatellar pain

10.  Lower most fibres of vastus
medialis
 Partly arise adductor magnus
 Straightens the pull on the quads
tendon and patella
 Controls patella tracking during
flexion extension of the knee
 Fibres atrophy quickly after knee
injury
 10-15 ml of effusion inhibit VMO
 VMO rehabilitation strength and
timing of contraction

11. Deficiency of Lateral Condyle

12.  Quadriceps
 Retinacular fibres
 Patellar tendon
 Coronary ligaments
 Medial and lateral
ligaments
 Posterior oblique ligament

13.  Quadriceps tendon
 The patella
 The patellar ligament
 Retinacular fibres all form the
anterior part of the capsule
 The patellar ligament is the insertion
of the quadriceps tendon

14.  Antero-inferiorly is attached to the
tuberosity of the tibia
 On either side the retinacular fibres
pass upwards from the tuberosity in
a V-shaped manner to be attached
just below the articular margin
 The deep infrapatellar bursa and
infrapatellar pad of fat lie posterior to
it, separating it from the tibia

15.  Laterally, the attachment is just beyond
the articular margin
 Laterally, it is attached above the groove
for the popliteus, below the lateral
epicondyle
 There is a gap in the capsule to allow
the popliteus to emerge

16.  Posterior
 Superiorly, it is attached just
beyond the articular margin
and to the lower border of
the popliteal surface of the
femur, above the
intercondylar notch

17.  Postero-inferiorly, the
capsule is attached to
the medial condyle of
the tibia
 By a line running
above the groove for
the semimembranosus
tendon
 Below the attachment
of the posterior
cruciate ligament

18.  Medially, the capsule is
attached to the femur
just beyond the articular
margin of the condyle
 Below the medial
epicondyle

19. Netter

20.  Medial ligament
 Pes anserinus consists
of:
 Sartorius
 Gracilis
 Semitendinosus
 Tibial inter-tendinous
bursa between them

21. Is attached superiorly to the
medial epicondyle of the femur
It blends with the capsule
Attached to the upper third of the
tibia, as far down as the tibial
tuberosity
It has a superficial and deep
portion
The deep portion, which is short,
fuses with the capsule
Attached to the medial meniscus
A bursa usually separates the
two parts

22. The tendons of
sartorius, gracilis and
semitendinosus cross its
tibial attachment where
another bursa is situated
The anterior part
tightens during the first
70–105°of flexion

23. Medial ligament, tightens in
extension
And at the extremes of medial
and lateral rotation
A valgus stress will put a strain
on the ligament
If gapping occurs when the knee
is extended, this is due to a tear
of posterior medial part of
capsule
If gapping only occurs at 15º
flexion, this is due to tear of
medial ligament

24. Netter

25.  Semimembranosus into
the groove on posterior
aspect of medial tibial
condyle and its extensions
 Upwards and lateral is
oblique popliteal ligament
 Downwards and lateral
forms fascia covering
popliteus
 Downwards and medially
fuses with medial ligament

26.  Oblique popliteal ligament
passes upwards and laterally
 Fuses with the fabella if
present
 Capsule above lateral femoral
condyle
 Pierced by middle genicular
vessels and nerve
 Posterior division of obturator
nerve
 Popliteal artery lies on it
Oblique Popliteal Ligament

27.  Strengthens the posterior portion
of the capsule and prevents
extreme lateral rotation
 It is an expansion from the
semimembranosus tendon close
to its insertion to the tibia
 Branch from the posterior division
of the obturator nerve, pierces the
ligament, supplies cruciates and
articular twig to knee (referred
pain from pelvic peritoneum to
knee)
Oblique Popliteal Ligament

28. Netter

29.  Lateral ligament
 Iliotibial tract
 Arcuate complex
• Fabellofibular ligament
• Deep portion of capsule
• Meniscotibial ligaments

30.  Posterior horn of
lateral meniscus
 Arcuate complex
 Popliteus
 Lateral head of
gastrocnemius

31.  Deep in interval between
iliotibial band and biceps
 Lateral epicondyle of
femur
 Midpoint superior surface
of fibula and the styloid
process of the fibula
 It is a cord-like structure
that is separated from the
capsule by the tendon of
the popliteus
 Surrounded by biceps
Fabbriciani & Oransky, 1992
Lateral Ligament

32.  Deep to lateral collateral
ligament
 Popliteus
 Inferolateral genicular
vessels and nerve

33.  Taut in extension
 20°flexion, lateral ligament
complex more lax than
medial
 Primary lateral restraint to
varus loading
 Arcuate ligament is the edge
of capsule that arches above
the popliteus

34.  Passes from the tip of the
styloid process
 Just posterior to the lateral
ligament
 Blends origin of the lateral
head of gastrocnemius and
oblique popliteal ligament
 Edge of capsule arches over
popliteus and may give
partial origin to popliteus

35.  Fabella lies at point
on the poster lateral
side of knee
 Where
multidirectional
collagenous tensile
stress meet
 8% - 10% osseous
 90% - 92%
cartilagenous
Fabbricani & Oransky, 1992

36.  Connects the periphery
of the menisci to the
tibia
 They are the portion of
the capsule that is
stressed in rotary
movements of the knee

37.  Origin inferior, popliteal
surface of tibia, above the
soleal line, fascia of
semimembranosus
 Deep to arcuate popliteal
ligament
 Enters capsule
 Crosses lateral surface of
lateral meniscus
 Attached by popliteal-
meniscal fibres which bound
hiatus

38.  Enters hiatus
 Crosses femoral
condyle
 Deep to lateral
collateral ligament
 Inserts into anterior
part of groove
 Superior popliteal
recess
communicates joint

39.  Femoral condyles
rotate medially around
taut ACL during the
locking mechanism of
the knee
 Popliteus laterally
rotates the femur to
unlock the knee so
flexion can occur

40.  The iliotibial tract is a thickening of the
deep fascia of the thigh, fascia lata
 The tract is attached to Gerdy’s tubercle
on the anterolateral aspect of the lateral
tibial condyle
 The superficial three quarters of the
gluteus maximus end in a thick tendinous
lamina which is inserted into the iliotibial
tract
 The tensor fascia lata is also inserted into
the tract
 Gives origin to the oblique fibres of the
vastus lateralis that help to stabilise the
patella

41.  In full knee extension the tract
lies anteriorly to the line of
flexion of the knee,
 As it is free of bony
attachments between the
lateral femoral epicondyle and
Gerdy’s tubercle
 It is free to move posteriorly to
this axis on flexion of the knee
Standish & Wood, 1996.
 As the tract crosses the lateral
epicondyle of the femur a
bursitis may develop as the
result of a ‘long-leg syndrome’

42.  The iliotibial band acts as an
extensor of the knee when the
knee is flexed from 0°to 30°and
as a flexor when the knee is
flexed more than 40°, due to the
change in the transverse axis
which occurs at
30–40°flexion.
 The pelvic tilt is a mechanism for
tightening the iliotibial band. The
pull of the band stabilises the
knee in extension, as well as
helping to resist extension and
adduction of the hip of the weight-
bearing leg

43.  Flexion and extension
take place between the
femoral condyles and
the upper surface of the
menisci
 Rotation occurs between
lower surface of the
menisci and upper
surface of the tibia

44.  Contraction of the quadriceps
results in extension
 The anterior cruciate becomes
taut
 And medial rotation of the
femur occurs around the taut
anterior cruciate to
accommodate the longer
surface of the medial condyle

45.  Femoral condyles rotate
medially around taut ACL
during the locking
mechanism of the knee
 Popliteus laterally rotates
the femur to unlock the
knee
 So flexion can occur
 Then the hamstrings flex
the knee

48.  Anatomically named by
their tibial attachments
 Clinically femoral are
called origin
 Covered by synovial
membrane on anterior
and on both sides which
is reflected from capsule,
 I.e. oblique popliteal
ligament
 Bursa between them on
lateral aspect
anterior
lateral

49.  Synovial membrane
covers the anterior and
sides of the cruciates
 Not covered on
posterior aspect
Anterior and Posterior
Cruciates Ligament

50.  Anterior cruciate is
attached to anterior aspect
of the superior surface of
the tibia behind
 Anterior horn of medial
meniscus in front of the
anterior horn of the lateral
meniscus
 Passes upwards and
laterally to the posterior
aspect of medial surface
of lateral femoral condyle
Anterior Cruciate

51. PCL
Anterior cruciate
ligament
Posterior meniscofemoral
ligament
Superior Aspect of
Tibial Plateau Menisci

52.  Three dimensional fan
shaped
 Multiple non-parallel
interlacing collagenous
fascicles
Anterior Cruciate Ligament (ACL)

53. anterior
Anterior Cruciate Ligament

54.  Tibial attachment is in
antero-posterior axis of
tibia
 Femoral attachment is in
longitudinal axis of femur
 Forms 40°with its long
axis
 90°twist of fibres from
extension to flexion
Anterior Cruciate Ligament

55.  Anteromedial fibres
have the most
proximal femoral
attachment
 Contribute to
anteromedial stability
 Intermediate to
straight and
anteromedial
 Posterolateral aids in
anteromedial stability
Anterior Cruciate Ligament

56.  ACL are vertical in
extension
 90°flexion are
horizontal
 PCL are more
vertical in 90°flexion
Anterior Cruciate Ligament

57.  At 0°of flexion the fibres of
the ACL are more vertical
 At 90°flexion they are in the
horizontal plane
 Fibres of the PCL are more
vertical with flexion and
increasing flexion,
> 90°becomes pivot
 PCL is least affective at
30°flexionHunziker et al 1992, Covey 2001
Cruciate

59.  PCL
 Provides 94% of
restraint to posterior
displacement
 ACL
 Provides 86% of
restraint to anterior
displacement
Anterior and Posterior Cruciate

60.  Middle genicular
artery
 Inferior medial
genicular
 Inferior lateral
genicular arteries via
infrapatellar fat pad
 Only one main
artery
 Middle genicular
enters upper third
Anterior Cruciate Ligament
Blood Supply

61.  Strongest ligament
 Shorter
 More vertical
 Less oblique
 Twice as strong as
ACL
 Posterior
Posterior Cruciate

62.  PCL is the strongest
ligament of the knee
 It is shorter
 More vertical
 Less oblique
 Twice as strong as
ACL
 Closely applied to the
centre of rotation of
knee
 It is the principal
stabiliser
Hunziker et al.,1992
Posterior Cruciate

63.  The tibial attachment of
the PCL was on the
sloping posterior portion
of the tibial
intercondylar area
 Anterior to tibial
articular margin
 Blends with periosteum
and capsule
 Extended 11.5-17.3 mm
distal to the tibial
plateau
Javadpour & O’Brien, 1992

64. Frazer, 1965
Tibial Attachment of the PCL

65.  Anatomically the fibres pass
anteriorly and medially and
proximally
 It is attached on the antero-
inferior part of the lateral
surface of the medial
femoral condyle
 The area for the PCL is
larger than the ACL
 It expands, more on the
apex of the intercondylar
notch than on the inner wall
Hunziker et al.1992
.
Posterior Cruciate

66.  Three functional bands
 Names vary
 Anterior or anterolateral is
larger
 Central
 Taut in flexion
 Posterior or posteromedial
taut in extension
 Posterior oblique bundle
Hunziker et al 1992
Posterior Cruciate Ligament

67.  Insertions of the PCL
 Passes through four
zones
 Ligament
 Fibrocartilage
 Tidemark of mineralised
fibrocartilage
 Bone in less than 1 mm
Cooper & Misol, 1970; Fabbriciani & Oransky, 1992
Attachment of PCL

68.  Posterior oblique bundle
 Most posterior fibres
 Attached to
posterosuperior part of
femur
 Posterior medial part on
intercondylar area of
tibia
 Longest fibres
 Tense in full extension
Fredrick & O’Brien, 1992; Hunziker et al.,1992
Posterior Cruciate Ligament

69.  Proximal fibres on femur
 Posterior fibres on the tibia
are longest
 Undergo least change
Posterior Cruciate

70.  The PCL is located
near the longitudinal
axis of the knee
 Medial to the centre of
the knee
 Vertical in frontal
plane
 30°to 35°in sagittal
 More horizontal in
sagittal with increased
flexion
Posterior Cruciate

71.  PCL provides 94% of
restraint to posterior
displacement of the tibia
 Prevents external rotation of
tibia more at 90°than at 30°
 ACL 86% of restraint to
anterior displacement
Posterior Cruciate

72. Blood Supply of Cruciates

73.  Posterior cruciate is
supplied by four
branches
 Distributed fairly
evenly over its course
 Subcortical vascular
network at bony
attachments
 Don’t contribute much
to ligaments
Sick & Koritke, 1960
Blood Supply of Cruciates

74.  Main is middle genicular
artery enters upper third
of PCL
 Synovium surrounding
PCL also supplies the PCL
 Contributions inferior
medial, inferior lateral
genicular arteries via
infrapatellar fat pad
 Periligamentous and intra-ligamentous
plexus
 Very little from bony attachment
Arnoczky 1987
Blood Supply of PCL

75.  Branches of tibial
and obturator
nerves
 Mechanoreceptors
 Proprioceptive
action
Posterior Cruciate Ligament
Nerve Supply

76.  Branches of tibial
nerve
 Middle genicular nerve
 Obturator nerve (post)
 Branches of the tibial
nerve enter via the
femoral attachment of
each ligament
 Nerve fibres are found
with the vessels in the
intravascular spaces
Nerve Supply of Cruciates

77.  Three types
 Found near the femoral
attachment
 Around periphery
 Superficially, but well below the
synovial lining.
 Where maximum bending
occurs
 Ruffini endings
 And ones resemble golgi
tendon organs
 Paccinian
 Proprioceptive function

78.  Mechanoreceptors
resembling golgi tendons
 Running parallel to the
long axis of the ligament
 Found near the femoral
attachment
 Around the periphery,
where maximum bending
occurs
 Posterior division of
obturator nerve

79.  There is a gradual change in
stiffness between the flexible
ligamentous tissue and bone
 There is a transitional zone of
fibrocartilage between
collagen and bone
 This helps to prevent the
concentration of stress at the
attachment site
Beynnon, 2000; Hunziker et al.,1992
Posterior Cruciate Ligament
Bony Attachment

80.  Menisci are made of
fibro cartilage
 Wedge shaped on
cross section
 Medial is comma
shaped with the wide
portion posteriorly
 Lateral is smaller, two
horns closer together
round
 They are intracapsular
and intra synovial
anterior

81.  Anterior to posterior
 Medial, anterior horn is
attached to the
intercondylar area in
front of the ACL and
the anterior horn of the
lateral meniscus
 Posterior horn of
lateral, posterior horn
of medial and PCL
 Medial is more fixed
 Lateral more mobile
anterior

82.  Medial is attached to the
deep portion of medial
collateral ligament
 Lateral is separated from
lateral ligament by the
inferolateral genicular
vessels and nerve
 The popliteus, which is
attached to lateral
meniscus
 Posterior horn gives
origin to meniscofemoral
ligament

83.  Coronary ligaments
are the portion of the
capsule attached to
the periphery of
meniscus, which
connects it to the tibia
 Synovial membrane,
stops at the upper
border of the
meniscus
 Lines the deep aspect
of the coronary
ligament

84.  Blood supply at the
periphery only
 Flexion and extension
takes place at the
upper surface of the
menisci
 Rotation occurs
between the lower
surface of the menisci
and the tibia anterior

85.  Shock absorption
 Redistributes forces
 Spread synovial fluid
 Minimal effect on stability
 On rotation menisci move with
femur
 Lateral moves 20 - 24 mm
 Medial less mobile 10 -15 mm
 Lateral meniscus bears more
load
Function of Menisci

86.  Anterior and posterior arise
from posterior horn of
lateral meniscus
 Anterior attached to femur
anterior to PCL
 Posterior attached
posterior to PCL
 More variations in posterior

87.  The Anterior meniscofemoral
(Humphrey) is attached to
lateral aspect of the medial
femoral condyle in front of the
PCL
 The posterior (Wrisberg) is
attached posterior to the PCL
 The posterior meniscofemoral
ligament is usually present
 Vary in size

89.  Increase with age
 Compact lobules
 With fibro-elastic
interlobular septa
 Septa well vascularised
 Provide firmness,
deformability and elastic
recoil
Williams & Warick,1980

90.  Superiorly
 Fills the space between the
inferior pole of the patella
 The ligamentum patella and
deep infrapatella bursa
 Attached to intercondylar
notch via ligamentum
mucosum
Williams & Warick,1980

91.  Posteriorly
 Covered by synovial
membrane
 Forms alar folds
 Femoral condyles
 Intercondylar notch
by ligamentum
mucosum
 Attached to anterior
horns of menisci
 Proximal tibia
Williams & Warick,1980

92.  Blood supply inferior
genicular arteries
 Also supply the lower
part of the ACL from
network of synovial
membrane of fat pad
 Centre of fat pad
limited blood supply
 Lateral arthroscopic
approach to avoid
injury
Kohn et al., 1995; Eriksson et al., 1980

93.  Can only expand anteriorly
 Inflammation of IFP
 Bulges on either side of
patellar tendon
 Synovial membrane is
compressed by femoral
condyles
 Pain and inflammation

94. • Intrinsic
• Hoffa’s disease
• Intracapsular chondroma
• Localised nodular synovitis
• Post-arthroscopy / post-surgery fibrosis
• Shear injury
• Torsion

95.  Hyperextension injury
 Genu recurvatum and
tilted inferior pole of patella
 Tenderness distal to
patella
 Beyond margins of the
patella
Brukner & Khan, 2000; Garret et al., 2000

96.  Anterior extra
capsular disorders
 Patellar fracture
 Patellar tendon
rupture
 Deep infrapatellar
bursitis
 Patellar tendonosis

97. Osgood-Schlatter Disease Sinding-Larsen Johanssen Disease

98.  ACL repair with patellar tendon
may result in fibrosis of fat pad
and pain
 Delays rehabilitation
 Inflammation of IFP may be
process leading to fibrosis
Murakami et al., 1995

100.  The synovial membrane
is very extensive
 It lines the inner aspect
of the capsule and the
non-articular structures
inside the capsule,
except posteriorly where
it is carried forwards to
cover the anterior and
sides of the cruciate
ligaments

101.  It covers the infrapatellar pad of
fat, forming the alar folds
 The ligamentum mucosum is
attached to the intercondylar
notch at the apex of the alar fold
 The alar folds increase the
surface area of the synovial
membrane via the infrapatellar
pad of fat,
 Which fill the changing spaces
during movement of the joint and
help to redistribute the synovial
fluid

102.  The synovial membrane is
continuous with:
 The suprapatellar bursa
which extends a hand’s
breadth above the patella.
This bursa always appears
distended when there is a
haemarthrosis or traumatic
synovitis in the knee joint
 Many other bursae, e.g.
around the popliteus and
under the medial head of
the gastrocnemius

103.  A suprapatellar plica may
separate the suprapatellar
bursa from the synovial
membrane of the knee joint
 Plicae folds may also be
found on either side of the
patella

105. Patellar Tendinitis / SLJ
Fat pad impingement
Infrapatellar Bursitis
Traction Apophysitis
Fractures & Instability
Patellofemoral syndrome
Prepatellar bursitis
Synovial plica

106.  Anatomical
anomalies
 Femoral torsion
 Genu valgum
 Increased Q-
angle
 High (alta)
patella
 Tibial torsion
 Overpronation
Q Angles
Males 140
Females 170
> 200
greater problems

107.  Anterior cruciate tear
 Bone bruising
 Posterior cruciate tear
 Osteochondritis
 Synovial plica

108. Traumatic
 Meniscal tears
 Ligament tears
 Cruciates
 Collaterals
 Patellar dislocations
 Fractures
 Patella
 Tibial plateau
 Articular cartilage damage
Atraumatic
 Patellofemoral syndrome
 Malalignment
 Dislocations
 Subluxations
 Iliotibial band syndrome
 Popliteus tendinopathy
 Patellar tendinitis
 Osgood-Schlatter’s
 Fat pad impingement

109. • Medial ligament tear
• Anterior cruciate tear
• Torn medial meniscus

110.  Valgus / External rotation
 Posterior horn of medial
meniscus trapped by
posterior condyles

112. • Medial meniscus has higher incidence but
less morbidity
• Traumatic tears
• Twisting on a planted, flexed knee
• Atraumatic tears
• Degenerative wear and tear