- Two condylar joints – Between femur and tibia
- One sellar joint – Between femur and patella
Knee joint has two articular compartments.
- Medial and lateral condyles of the femur articulate with the tibial condyles
- Medial and lateral condyles are partially seperated by synovial membrane and cruciate ligaments
- Anterior aspect of the distal femur articulates with the patella
- Ligamentum patellae which is considered as a part of the quadriceps tendon attaches here and stabilizes the joint in full extension
Knee joint capsule is a complex structure which consist of an inner synovial membrane & an outer fibrous membrane separated by fatty tissue.
Fibrous capsule of knee joint is a complex structure which is made up by a collection of adjacent ligaments.
Structures that penetrate the capsule are….
- Popliteus tendon penetrates the capsule and is covered by synovial membrane (Intracapsular tendon)
- Middle geniculate artery, a branch of popliteal artery – Supplies the capsule, synovial membrane, cruciate ligaments and menisci
These are synovial fluid filled sacs that reduce wear and tear of the knee joint.
- Suprapatella bursa
- Largest bursa
- Communicates with the joint space
- Located between the quadriceps femoris and the femur
- Prepatella bursa
- Located between the patella and the skin
- Infrapatella bursa
- Deep infrapatella bursa – Lies between the distal tibial tuberosity and the patella ligament
- Subcutaneous infrapatella bursa – Lies between the patella ligament and the skin
- Semimembranosus bursa
- Located posteriorly and the position is highly variable
- There are several bursa situated medially and laterally
C shaped fibrocartilagious structures that are present on the articular surfaces of femur and tibia.
- Two menisci present
- Medial and lateral menisci
- Lateral meniscus is smaller than medial meniscus
- Deepens the articular surface to compensate the incongruence of femoral and tibial condyles
- Shock absorption
- Medial meniscus is attached to the tibial collateral ligament
- Lateral meniscus is attached to the loose fibers at the lateral edge of the joint
- Medial collateral ligament
- Attachment – Medial epicondyle of the femur to medial condyle of the tibia
- Responsible for valgus stability
- Lateral collateral ligament
- Attachment – Lateral epicondyle of the femur to the fibular head
- Responsible for varus stability
- Anterior cruciate ligament
- Attachment – Anterior intercondylar region of the tibia to lateral intercondylar notch of femur
- Prevents tibia from sliding anteriorly
- Posterior cruciate ligament
- Attachment – Posterior intercondylar region of the tibia to medial intercondylar notch of femur
- Prevents tibia from sliding posteriorly
- Patellar ligament
- Attachment – Continuation of quadriceps tendon and attaches to the tibial tuberosity
Knee joint is supplied by….
- Genicular branches of femoral artery
- Politeal artery
- Anterior tibial artery
Innervation of knee joint includes….
- Femoral nerve
- Tibial nerve
- Common peroneal nerve
- Obturator nerve
Movements Of Knee Joint
- By hamstring muscles, gracilis, sartorius and popliteu
- By the quadriceps femoris
- Medial rotation
- By semimembranosus, semitendinosus, gracilis, sartorius and popliteus
- Lateral rotation
- By the biceps femoris
To learn more about knee joint diseases, please click on the link below.