The knee joint is composed of three joints within a synovial cavity. It allows for both hinge-like flexion and extension as well as some rotational movement. The knee joint is supported by ligaments such as the ACL, PCL, and collateral ligaments as well as menisci that act as shock absorbers. Common knee joint issues include osteoarthritis, which involves the destruction of cartilage over time, and various injuries to structures like the menisci and ligaments that can compromise stability.
3. - The Knee Joint is the largest & most complicated joint
in the body .
- It consists of 3 Joints within a single synovial cavity :
1) Medial Condylar Joint : Between the medial condyle
“of the femur” & the medial condyle “of the tibia” .
2) Lateral Condylar Joint : Between the lateral condyle
“of the femur” & the lateral condyle “of the tibia” .
3) Patellofemoral Joint : Between the patella & the
patellar surface of the femur .
- The fibula is NOT directly involved in the joint .
7. Capsule
Femoral attachment
Anteriorly it is deficient
Posteriorly it is attached to intercondylar ridge
Laterally encloses the origin of poplitieus
Tibial attachment
Anteriorly it descend to the tibial tuberosity along
margins of the condyles
Posteriorly it is attached to intercondylar ridge
Posterolaterally passage of popliteus tendon
8. The weak capsular ligament is strengthened by
Anteriorly by medial and lateral retinacula
(extensions of v. medialis & v. lateralis )
Laterally by iliotibial tract
Posteriorly by oblique polpliteal ligament
Medially by tendons of sartorius and
semimembranosus
9. Ligamentum patellae
Attachment
Above – margins and rough posterior margins of
patellar retinacular
Below- smooth upper part of tibial tuberosity
Related to deep and superficial infrapatella bursa ,
infrapatella pad of fat
10. Tibial collateral or medial ligament
This is a long band of great strength
Attachments
Superioly –medial epicondyle of femur
Inferioly -anterior part & posterior part
Anterior part- below to medial border of medial surface
of shaft of tibia
(covers inferior medial genicular vessels and nerve
,anterior part of semimembranosus tendon)
Posterior part – medial condyl of tibia above groove for
semetendinosus
(blends with medail meniscus and capsule)
11. Fibular collateral or lateral ligament
Strong and code like ligament
Attachments
Superiorly –lateral epicondyle of femur below to
popliteal groove
Inferiorly head of fibula in front of its apex
(it is separated from lateral meniscus from capsule
and tendon of popliteus)
12. Oblique popliteal ligament
This is an expansion of semimembranosus tendon
which runs upwards and laterally
Attached to intracondylar line and lateral condyle
of femur
Have a close relation with popliteal artery
13. Arcuate popliteal ligament
Posterior expansion of short lateral ligament
It expands backwards from head of the fibula ,
arches over tendon of poplitieus and attached to
the posterior border of intracondylar region of tibia
Anterior & Posterior cruciate ligaments
Both are very strong and thick fibrous bands they
act directly to maintain anteroposterior stability of
knee joint
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17. Anterior Cruciate Ligament (ACL) :
Attached to the anterior intercondylar area
of the tibia , passes upward , backward &
laterally to get attached to the lateral femoral
condyle .
Prevents posterior displacement of the
femur ( With the knee joint flexed , the ACL
prevents the tibia from being pulled anteriorly)
18. ~ Posterior Cruciate Ligament (PCL)
Attached to the posterior intercondylar area of
the tibia , passes upward , forward , & medially
to get attached to the medial femoral condyle.
Prevents anterior displacement of the femur
( With the knee joint flexed , the PCL prevents
the tibia from being pulled posteriorly ).
19. - The medial and lateral menisci are 2 C-
shaped sheets of fibrocartilage between the
tibial & femoral condyles
- Their peripheral border is thick & attached to
the capsule and vascular
their inner border is thin & forms a free edge
and avascular
- Each meniscus is attached to the upper
surface of the tibia by anterior & posteriorly
- They are connected to each other by the
transverse ligament and to the margins of
the head of the tibia by coronary ligaments.
20. Medial menisci Lateral menisci
Nearly semicircular Nearly circular
Posterior fibers of anterior
end continues with the
transverse ligament
Posterior end of meniscus is
attached to the femur
through two meniscofemoral
ligaments
Peripheral part attach with
deep part of tibial collateral
ligament
Medial part of tendon of
politius attach to lateral
meniscus
Functions
•Make articular surfaces more congruent
•Act as shock absorbers
•Lubricate joint cavity
•Give rise to proprioceptive impulses due to their nerve supply
21. Synovial membrane lines the capsule except
posteriorly where it is forwards by cruciate
ligaments
In front it is absent from patella
Below it covers the deep surface of infrapatellar
fatty pad
Medially the infrapatellar synovial fold extend
backwards from fatty pad to intercondylar fossa of
femur
22. There are 13 bursae around knee joint
4 anteriorly
4 laterally
5 medially
23. Flexion and extension are take place in upper
compartment of the joint
Flexion : these muscles produce flexion :
Biceps femoris , Semitendinosus ,
Semimembranosus , Gracilis, Sartorius , Popliteus .
Flexion is limited by the contact of the back of the leg
with the thigh .
Extension : by the Quadriceps femoris , tensor
fasciae latae
Extension is limited by the tension of all the ligaments
of the joint .
25. Raotatry movements at the knee take place in
lower compartment around a vertical axis
- Medial Rotation : by the Semtendinosus ,
Semimembranosus, Popliteus Sartorius ,
Gracilis
- Lateral Rotation : by the Biceps femoris .
28. Osteoarthritis (OA) : a chronic inflammatory joint
disorder in which there’s progressive softening &
destruction of the articular cartilage , accompanied
by new growth of cartilage and bone at the joint
margins (osteophytes) and capsular fibrosis...
leading to bone exposure & severe pain .
OA is the most common joint disease.
The knee is the most common site.
32. It is an angle formed by two intersecting lines
anterior superior illiac spine mid patella
tibial tubercle mid patella
10° - 15° in male
10° - 19° in female
Increase of the angle causes the Genu Valgum
( knock knee )
Decrease of the angle causes the Genu Varus
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34. Injuries to menisci
Injuries to crucial ligaments
Injuries to collateral ligaments
