Knee Anatomy

  • The knee joint is less mobile than others (e.g. the hip) due the greater load requiring more stability
  • Articulates at tibial plateau.
    • Facets for medial and lateral condyles of femur
  • Relatively poor articulation, ↑stability by the use of:
    • Muscles
    • Ligaments
    • Menisci

Knee menisci

  • Wedge-shaped and cartilaginous structures
    • Thicker laterally
    • Also curved to articulate with condyles
  • Functions:
    • Act as shock absorbers
      • Spread the load of the weight
    • Increase stability by holding in joint in place (↑congruence)
    • Reduce friction between condyles

Knee ligaments

  1. Collateral ligaments – these maintain the ‘column’ by preventing adduction/abduction of the femur
    1. Medial – over tibia
    2. Lateral – over fibula
  2. Cruciate ligaments – Prevent anterior/posterior slipping of the femur
    1. Anterior
    2. Posterior

Knee Muscles

  • Consider
    1. Flexors
    2. Extensors
Knee Flexion
  1. Mainly done by the Hamstrings (also extend hip)
  2. Sartorius – essentially helps with all movements to sit cross-legged (hip abduction, hip flexion, knee flexion)
    • NB it is a weak muscle
    • Innervated by femoral nerve (L2-L3)
    • NB this is also the longest muscle in the human body
  3. Gracilis
    • Also adducts hip

Knee Extension
  • This is done by the group of muscles known as quadriceps femoris
    • All insert into the quadriceps tendon and onto tibial tuberosity
    • All innervated by Femoral nerve (L2-L4)
  1. Vastus medialis
  2. Vastus intermedius
  3. Vastus lateralis
  4. Rectus femoris
    • This is more superficial than the other 3 muscles