Anatomy Of Knee Joint

Knee joint is the largest and the most complex joint of the body. It is a hinge type synovial joint. It consists of ….

  • Two condylar joints – Between femur and tibia
  • One sellar joint – Between femur and patella

Compartments 

Knee joint has two articular compartments.

  • Tibiofemoral
    • 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 
  • Patellofemoral
    • 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

Articular Capsule

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 

Bursae

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 
  • Others
    • There are several bursa situated medially and laterally 

Menisci

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 
  • Function
    • Deepens the articular surface to compensate the incongruence of femoral and tibial condyles
    • Shock absorption 
  • Attachments
    • Medial meniscus is attached to the tibial collateral ligament 
    • Lateral meniscus is attached to the loose fibers at the lateral edge of the joint

Ligaments

  • 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

Blood Supply

Knee joint is supplied by….

  • Genicular branches of femoral artery
  • Politeal artery
  • Anterior tibial artery 

Nerve Supply

Innervation of knee joint includes….

  • Femoral nerve
  • Tibial nerve
  • Common peroneal nerve
  • Obturator nerve 

Movements Of Knee Joint

  • Flexion
    • By hamstring muscles, gracilis, sartorius and popliteu
  • Extension
    • 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. 

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1 year ago

[…] join is the largest joint in the human body which can easily be injured, specially in sportsmen. Anatomy Of Knee Joint It is composed of several […]