Movements Of Knee Joint

  • There are four main movements that the knee joint permits:
  • Extension: Produced by the quadriceps femoris, which inserts into the tibial tuberosity.
  • Flexion: Produced by the hamstrings, gracilis, sartorius and popliteus.
  • Lateral rotation: Produced by the biceps femoris.
  • Medial rotation: Produced by five muscles; semimembranosus, semitendinosus, gracilis, sartorius and popliteus.
Normal range of motion of knee is
  • Flexion – 120-150 degrees
  • Internal rotation with knee flexed – 10 degrees
  • External rotation with knee flexed – 30-40 degrees
  • The total range of motion is dependent on several parameters such as soft-tissue restraints, active insufficiency, and hamstring tightness.
  1. Flexion and extension are the chief movements. These take place in the upper compartment of the joint, above the menisci.
  2. They differ from the ordinary hinge movements in two ways
  3. Transverse axis around which these movements take place is not fixed.
  4. During extension, the axis moves forwards and upwards, and in the reverse direction during flexion.
  5. The distance between the center and the articular surfaces of the femur changes dynamically with the decreasing curvature of the femoral condyles.
  6. These movements are invariably accompanied by rotations (conjunct rotation).
  7. When a person gets up from sitting position the femur internally (medially) rotates on the fixed tibia.
  8. Medial rotation of the femur occurs during the last 30 degrees of extension and
  9. In full extension collateral ligaments are taut
  10. When the foot is off the ground, the tibia rotates instead of the femur, in the opposite direction.
  1. Rotatory Movements at the knee are of a small range.
  2. Rotations take place around a vertical axis, and are permitted in the lower compartment of the joint, below the menisci.
  3. Rotatory movements may be combined with flexion and extension (conjunct rotations), or may occur independently in a partially flexed knee (adjunct rotation).
  4. In the flexed position, the collateral ligaments are relaxed while the cruciate ligaments are taut. Rotation is controlled by the twisted cruciate ligaments
  5. The conjunct rotations are of value in locking and unlocking of the knee.
  1. Passive movements can be performed in a partially flexed knee.
  2. There is lack of conformity between bony surfaces that allows translating movements in three planes.
This movement include
  1. A wider range of rotation
  2. Anteroposterior gliding of the tibia on the femur
  3. Some adduction
  4. Some separation of the tibia from the femur.
  • Locking is a mechanism that allows the knee to remain in the position of full extension without much muscular effort.
  • Locking occurs as a result of medial rotation of the femur during the last stage of extension caused by Osgood shalter & Loose body in knee joint
  • As compared to the medial femoral condyle, the articular surface of the smaller lateral femoral condyle is a rounder and flattens more rapidly anteriorly.
  • As a result when the lateral condylar articular surface if fully used up by extension, part of the medial condylar surface remains unused.
  • Lateral condyle of the femur attains a congruent relationship with its opposed tibial meniscal surface, about 30° before full extension has been obtained.
  • To achieve full extension, the lagging medial compartment must medially rotate about a fixed vertical axis while moving backwards in an arc.

Extension 5-10° Flexion 120-150°
(withsome assistance fromthe Tensor fasciae latae )
Chief extensor of knee joint in hip flexion is
Rectus femoris
(In order of importance)
Biceps femoris

Internal rotation* 10° External rotation* 30-40
(In order of importance)
Biceps femoris
*(knee flexed 90°)
Exam Question
  • When a person gets up from sitting position the femur internally (medially) rotates on the fixed tibia.
  • Abduction of hip , Flexion of hip ,Extension of knee are the action of tensor fasciae latae
  • Extension at the knee is caused by quadriceps femoris muscle
  • Popliteus unlocks knee
  • Chief extensor of knee joint in hip flexion is Rectus femoris
  • Extension of knee joint is caused by Quadriceps femoris
  • Flexion is coupled with lateral rotation
  • In full extension collateral ligaments are taut
  • Locking of knee joint can be caused by Osgood shalter & Loose body in knee joint
  • Biceps femoris responsible for Lateral Rotaion of Flexed Knee Joint
Don't Forget to Solve all the previous Year Question asked on Movements Of Knee Joint