• Skip to main content
  • Skip to primary sidebar
  • Skip to footer
  • General Ortho
  • Procedures
  • Spine
  • Upper Limb
  • Lower Limb
  • Pain
  • Trauma
  • Tumors
  • Newsletter/Updates
  • About Us
  • Contact Us

Bone and Spine

Orthopedic health, conditions and treatment

Knee Range of Motion and Movements

By Dr Arun Pal Singh

In this article
    • Normal Knee – Range of Motion
  • Flexion-Extension Movement of Knee
  • Rotatory Movements of Knee
  • Passive Movements of Knee
  •  Locking and Unlocking of the knee joint
  • Flexion and Extension Movements of Knee in Detail
    • Muscles Involved in Knee Movement

The knee joint is a modified hinge joint (ginglymus).  The knee joint is not a very stable joint. Knee range of motion is through following movements-

  • Flexion
  • Extension
  • Medial rotation
  • Lateral rotation

The femur and lateral meniscus move over the tibia during rotation, while the femur rolls and glides over both menisci during extension-flexion. Thus the flexion-extension movement occurs in the compartment above the menisci whereas the rotator movement occurs below the menisci.

range of motion of knee
Image Credit: Military Disability

 

Normal Knee – Range of Motion

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.

Flexion-Extension Movement of Knee

Flexion and extension are the chief movements. These take place in the upper compartment of the joint, above the menisci.

They differ from the ordinary hinge movements in two ways

  • The transverse axis around which these movements take place is not fixed. During extension, the axis moves forwards and upwards, and in the reverse direction during flexion. The distance between the center and the articular surfaces of the femur changes dynamically with the decreasing curvature of the femoral condyles.
  • These movements are invariably accompanied by rotations (conjunct rotation). Medial rotation of the femur occurs during the last 30 degrees of extension and lateral rotation of the femur occurs during the initial stages of flexion when the foot is on the ground. When the foot is off the ground, the tibia rotates instead of the femur, in the opposite direction.

Rotatory Movements of Knee

Rotatory Movements at the knee are of a small range. Rotations take place around a vertical axis, and are permitted in the lower compartment of the joint, below the menisci.

Rotatory movements may be combined with flexion and extension (conjunct rotations) or may occur independently in a partially flexed knee (adjunct rotation).

In the flexed position, the collateral ligaments are relaxed while the cruciate ligaments are taut. Rotation is controlled by the twisted cruciate ligaments

The conjunct rotations are of value in locking and unlocking of the knee.

Passive Movements of Knee

Passive movements can be performed in a partially flexed knee. There is a lack of conformity between bony surfaces that allows translating movements in three planes.

This movement includes

  • A wider range of rotation
  • Anteroposterior gliding of the tibia on the femur
  • Some adduction
  • Some separation of the tibia from the femur.

 Locking and Unlocking of the knee joint

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.

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.

The lateral condylar servers as an axis around which the medial condyle rotates backwards [medial rotation of the femur] so that the remaining part of the medial condylar surface is also taken up. This locks the knee joint.

Locking is aided by the oblique pull of ligaments during the last stages of extension. When the knee is locked, it is completely rigid and all ligament of the joint are taut. Locking is produced by the continued action of the same muscles that produce extension i.e., the quadricps muscle.

The locked knee joint can be flexed only after it unlocked by a reversal of the medial rotation i.e., by lateral rotation of the femur. Unlocking is brought about by the action of the popliteus muscle and meniscal attachments.
It pulls downwards and posterior on its attachment to the lateral condyle of the and via its meniscal attachment the popliteus pulls on the posterior horn of the lateral meniscus.

Thus, while rolling back, the posterior motion of the menisci occurs in both compartments, but lateral more than medial.

Flexion and Extension Movements of Knee in Detail

This example considers foot fixed to the ground as in walking.

When the foot is fixed to the ground, the last 30° of extension is associated with medial rotation of the femur as explained above.

As the knee goes into extension, there is a progressive increase in the passive mechanism that resists further extension.  In full extension following structures are tight and resist further extension

  • Parts of both cruciate ligaments
  • Collateral Ligaments
  • Posterior capsule
  • Oblique posterior ligament complex
  • Skin and fascia

Moreover, there is also passive or active tension in the hamstrings, gastrocnemius muscles and the iliotibial band. Also, the anterior parts of the menisci compress between the femoral condyles and the tibia.

At the beginning of flexion, the knee unlocks by an external rotation of the femur on the tibia brought about by the opposite interplay of the meniscal articular and ligamentous structures and the contraction of the popliteus muscles.

Flexion is checked by the quadriceps mechanism, the anterior parts of the capsule and the PCL and by the compression of the soft tissue structures in the popliteal fossa.

Muscles Involved in Knee Movement

Extension 5-10°Flexion 120-150°
Quadriceps

Tensor fasciae latae [minor contribution]

Semimembranosus
Semitendinosus
Biceps femoris
Gracilis
Sartorius
Popliteus
Gastrocnemius
Internal rotation [Knee Flexed at 90°]External rotation [Knee Flexed at 90°]
Semimembranosus
Semitendinosus
Gracilis
Sartorius
Popliteus
Biceps femoris

You would get a visual idea by watching the knee movements.

Spread the Knowledge
  • 165
    Shares
  •  
    165
    Shares
  • 162
  • 3
  •  
  •  
  •  

Filed Under: Anatomy, General Ortho

About Dr Arun Pal Singh

Arun Pal Singh is an orthopedic and trauma surgeon, founder and chief editor of this website. He works in Kanwar Bone and Spine Clinic, Dasuya, Hoshiarpur, Punjab.

This website is an effort to educate and support people and medical personnel on orthopedic issues and musculoskeletal health.

You can follow him on Facebook, Linkedin and Twitter

Reader Interactions

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Primary Sidebar

bone mineral density scanner

Bone Mineral Density

Bone mineral density or bone density is measure of mineral content in per square centimeter of bones. Bone mineral density is an indirect indicator of osteoporosis. Densitometery is the test for measurement of bone mineral density. As we grow after reaching peak bone mass, we lose some bone mass because of loss of bone minerals […]

Kohler disease of patella

Kohler Disease of Patella

Osteochondrosis of the primary ossification center of the patella is also called Kohler disease [navicular osteochondrosis is also called Kohler disease]. For sake of differentiation, some authors also term it as Kohler disease of the patella.  It is a rare cause of knee pain in children between 5 and 9 years of age. It affects […]

Metastatic Calcification and Dystrophic calcification

Metastatic Calcification and Dystrophic Calcification

Metastatic calcification and dystrophic calcification are pathological calcification which means abnormal calcium deposits at the places where these are normally not found. Heterotopic ossification is another name for pathologic calcification and both metastatic and dystrophic calcification constitute heterotopic calcification. Normally, inorganic calcium salts are found in bones and teeth. Pathologic or heterotopic calcification is the […]

Periprosthetic Fracture Femur in a patient who had undergone bipolar hemiarthroplasy previously for fracture of neck of femur

Hip Injuries Xrays and Photographs

Hip injuries consist of injuries to the acetabulum, lower pelvis, intertrochanteric fractures, fracture of neck of femur, fracture of the femoral head, subtrochanteric fractures and hip dislocations. A collection of x-rays and clinical photographs of hip injuries is being presented. Image 1 –  Xray of Oblique Subtrochanteric Fracture of Femur With Dynamic Hip Screw and […]

Axillary nerve injury would affect its supply as shown

Axillary Nerve Injury – Causes, Effects and Treatment

Axillary nerve injury can result either from compression of the axillary nerve or traumatic injury resulting from traction, direct trauma or from injections. As deltoid is the muscle that is being supplied along with skin over the deltoid area, the axillary nerve injury causes deltoid muscle paralysis and numbness over the region. Axillary nerve injury is […]

Main groups of Allen classification of subaxal spine injuries

Allen Classification of Cervical Spine Injury

Allen classification of cervical injury is also called mechanistic classification and was given by  Allen and associates in 1982. The translation of kinetic energy into fractures and dislocations is determined by two independent variables Injury vector Posture of the cervical spine at the time of accident Allen et al presumed that identical segmental failures could […]

antitubercular chemotherapy doses

Antitubercular Chemotherapy in Musculoskeletal Tuberculosis

Antitubercular chemotherapy is the mainstay of the treatment of osteoarticular tuberculosis. It is complemented by rest, nutritional support and splinting, as necessary. The drugs and regimens are fundamentally similar to those for pulmonary TB. But there is a lack of consensus on the appropriate duration of treatment. Overview of Osteoarticular Tuberculosis The spine is probably […]

Browse Articles

Footer

Pages

  • About
    • Policies
    • Contact Us

Featured Article

Joint Aspiration or Arthrocentesis

Joint aspiration or arthrocentesis is the procedure by which joint fluid is withdrawn using a needle. The fluid withdrawn is used in diagnostic tests. … [Read More...] about Joint Aspiration or Arthrocentesis

Search Articles

© Copyright: BoneAndSpine.com