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Knee Joint Review

Overview of the Knee Joint

  • The knee joint consists of three separate joints:
    1. Tibiofemoral Joint
    • Joint between the tibia (shinbone) and femur (thigh bone)
    • The main joint commonly referred to as the knee joint.
    1. Patellofemoral Joint
    • Joint between the patella (kneecap) and femur
    • Allows movement independent of the tibiofemoral joint, influenced by quadriceps muscle movement.
    1. Tibiofibular Joint
    • Joint between the tibia and the fibula (the smaller bone next to the tibia).

Bony Landmarks of the Distal Femur

  • Focus on identifying key features in the distal femur:
    1. Condyles
    • Medial and lateral condyles are the large knobby parts at the bottom of the femur.
    • Important for articulating with the tibia during knee movement.
    1. Epicondyles
    • Medial and lateral epicondyles sit above the condyles.
    • Epicondyle (epi meaning above) is a knobby structure aiding in ligament attachment and muscle functions.
    1. Adductor Tubercle
    • Located on the medial epicondyle.
    • Insertion site for hip adductor muscles (e.g., adductor longus).

Bony Landmarks of the Patella and Tibia

  • Patella
    • Has a base (superior end) and apex (inferior end).
  • Proximal Tibia Features
    1. Tibial Plateaus
    • Articulate with the femoral condyles; they are the surfaces on the top of the tibia covered in cartilage.
    1. Tibial Tuberosity
    • Protruding bump on the anterior side of the tibia, insertion point for the quadriceps via the patellar tendon.
    1. Gertie’s Tubercle
    • Located on the superior and lateral part, it’s the insertion point for the iliotibial band.

Knee Ligaments

  • Joint Capsule
    • Encloses the knee joint, important for stability and production of synovial fluid.
  • Ligaments
    • Lateral Collateral Ligament (LCL)
      • Attaches from the lateral epicondyle of the femur to the head of the fibula.
    • Medial Collateral Ligament (MCL)
      • Extends from the medial epicondyle of the femur to the medial tibia.
  • Intracapsular Ligaments
    • Anterior Cruciate Ligament (ACL)
      • Attaches from the posterior lateral condyle of the femur to the anterior tibia, helps resist anterior tibial translation.
    • Posterior Cruciate Ligament (PCL)
      • Attaches from the posterior aspect of the femur to the posterior tibial plateaus, resists posterior tibial translation.

Quadriceps Muscles

  • Composed of four muscles:
    1. Rectus Femoris
    • Biarticular; crosses both hip and knee joints.
    1. Vastus Lateralis
    • Located on the lateral side.
    1. Vastus Medialis
    • Located on the medial side.
    1. Vastus Intermedius
    • Positioned between the vastus lateralis and medialis, cannot be palpated due to being deep to the rectus femoris.
  • All four muscles share a common tendon which inserts at the tibial tuberosity via the patellar tendon.

Muscle Functions

  • The quadriceps work together primarily for knee extension, decreasing redundancy and optimizing efficiency during knee movement.