section 3, chapter 8: knee joint and joint disorders
Chapter 8, Section 3
The Knee Joint and Joint Disorders
The knee joint is the largest and most complex synovial joint in body.
Two distal condyles of the femur
articulate with two proximal condyles
of the tibia. This is a condylar joint.
The femur also articulates anteriorly
with the patella. This is a plane joint.
General structures of a synovial joint in the knee
1. Synovial Membrane
• Secretes synovial fluid
2. Joint Cavity
• Stores synovial fluid
3. Joint Capsule
• Relatively thin support
• Reinforced by several
ligaments and tendons
Several ligaments and tendons
strengthen the knee joint.
1. Patellar tendon - The patella is
partially enclosed in tendons
fused together from the thigh
2. Patellar ligament – continuation of
patellar tendon. Extends from
patella to the tibial tuberosity.
3. Tibial collateral ligament –
connects medial condyle of femur
with medial condyle of tibia.
4. Fibular collateral ligament –
connects lateral condyle of femur
with head of fibula.
5. Anterior & Posterior Cruciate
ligaments – provide additional
support to medial surface of tibia
Figure 8.21a Anterior right knee
with patella removed.
Two menisci (medial & lateral meniscus)
separate the femur and tibia, and align them.
Figure 8.20 (a) sagittal section of the knee joint.
(b) Photograph of the left knee joint (frontal section)
Three major bursae surround the knee joint.
1. Suprapatellar bursa
Largest bursa in body
2. Prepatellar bursa
Between patella and skin
Housemaid’s knee =
3. Infrapatellar bursa
Sprain = overstretching or tearing of
connective tissue (tendons, ligaments, or
cartilage) associated with a joint.
However, the bones are not disarticulated.
Arthritis = inflamed, swollen, and painful joints.
• Most common arthritis
Occurs with aging
Articular cartilage degenerates,
causing bone to rub against bone.
Results in stiff and painful joints
Fingers may appear gnarled and
knee may bulge.
Osteoarthritic fingers often take
on a gnarled appearance.
2. Rheumatoid Arthritis
• Autoimmune disorder (immune
system attacks tissue)
Synovial membrane thickens &
Mass of fibrous connective tissue
(Pannus) invades synovial space.
Fibrous pannus destroys articular
cartilage, and the joints may swell
Other symptoms of Rheumatoid Arthritis:
• low-grade fever, fatigue, appetite, stiffness.
Knuckles may swell as a result of
End of Chapter 8, Section 3