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.