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Knee Anatomy

The knee is a complex joint made up of different structures - bones, tendons, ligaments, and muscles. They all work together to maintain the knee’s normal function and provide stability to the knee during movement.

Having a well-functioning healthy knee is essential for our mobility and ability to participate in various activities. Understanding the anatomy of the knee enhances your ability to discuss and choose the right treatment procedure for knee problems with your doctor.

Bones of the Knee

The knee is a hinge joint made up of two bones, the thighbone (femur) and shinbone (tibia). There are two round knobs at the end of the femur called femoral condyles that articulate with the flat surface of the tibia called the tibial plateau. The tibial plateau on the inside of the leg is called the medial tibial plateau and on the outside of the leg, the lateral tibial plateau.

The two femoral condyles form a groove on the front (anterior) side of the knee called the patellofemoral groove. A small bone called the patella sits in this groove and forms the kneecap. It acts as a shield and protects the knee joint from direct trauma.

A fourth bone called the fibula is the other bone of the lower leg. This forms a small joint with the tibia. This joint has very little movement and is not considered a part of the main joint of the knee.

Articular Cartilage and Menisci of the Knee

Movement of the bones causes friction between the articulating surfaces. To reduce this friction, all articulating surfaces involved in the movement are covered with a white, shiny, slippery layer called articular cartilage. The articulating surface of the femoral condyles, tibial plateaus and the back of the patella are covered with this cartilage. The cartilage provides a smooth surface that facilitates easy movement.

To further reduce friction between the articulating surfaces of the bones, the knee joint is lined by a synovial membrane that produces a thick clear fluid called synovial fluid. This fluid lubricates and nourishes the cartilage and bones inside the joint capsule.

Within the knee joint, between the femur and tibia, are two C-shaped cartilaginous structures called menisci. Menisci function to provide stability to the knee by spreading the weight of the upper body across the whole surface of the tibial plateau. The menisci help in load-bearing i.e. it prevents the weight from concentrating onto a small area, which could damage the articular cartilage. The menisci also act as a cushion between the femur and tibia by absorbing the shock produced by activities such as walking, running and jumping.

Ligaments of the Knee

Ligaments are tough bands of tissue that connect one bone to another bone. The ligaments of the knee stabilize the knee joint. There are two important groups of ligaments that hold the bones of the knee joint together, collateral and cruciate ligaments.

Collateral ligaments are present on either side of the knee. They prevent the knee from moving too far during side to side motion. The collateral ligament on the inside is called the medial collateral ligament (MCL) and the collateral ligament on the outside is called the lateral collateral ligament (LCL).

Cruciate ligaments, present inside the knee joint, control the back-and-forth motion of the knee. The cruciate ligament in the front of the knee is called anterior cruciate ligament (ACL) and the cruciate ligament in the back of the knee is called posterior cruciate ligament (PCL).

Muscles of the Knee

There are two major muscles in the knee - the quadriceps and the hamstrings, which enable movement of the knee joint. The quadriceps muscles are located in front of the thigh. When the quadriceps muscles contract, the knee straightens. The hamstrings are located at the back of the thigh. When the hamstring muscles contract, the knee bends.

Tendons of the Knee

A tendon is a tissue that attaches a muscle to a bone. The quadriceps muscles of the knee meet just above the patella and attach to it through a tendon called the quadriceps tendon. The patella further attaches to the tibia through a tendon called the patella tendon. The quadriceps muscle, quadriceps tendon, and patellar tendon all work together to straighten the knee. Similarly, the hamstring muscles at the back of the leg are attached to the knee joint with the hamstring tendon.

Knee Conditions

  • Knee Arthritis

    Knee Arthritis

    The joint surface is covered by a smooth articular surface that allows pain-free movement in the joint.

  • Knee Pain

    Knee Pain

    Knee pain is a common condition affecting individuals of various age groups. It not only affects movement but also impacts your quality of life.

  • Knee Fracture

    Knee Fracture

    A fracture is a condition in which there is a break in the continuity of the bone. In younger individuals, these fractures are caused by high energy injuries, as from a motor vehicle accident.

  • Knee Injury

    Knee Injury

    A knee injury can affect any of the ligaments, tendons or fluid-filled sacs (bursae) that surround your knee joint as well as the bones, cartilage and ligaments that form the joint itself.

  • Patellar Tendon Rupture

    Patellar Tendon Rupture

    A Patellar Tendon Rupture can affect any of the ligaments, tendons or fluid-filled sacs (bursae) that surround your knee joint as well as the bones,

  • Knee Sprain

    Knee Sprain

    Knee sprain is a common injury that occurs from overstretching of the ligaments that support the knee joint.

  • Meniscal Tears

    Meniscal Tears

    A meniscal tear is a common knee injury in athletes, especially those involved in contact sports. A sudden bend or twist in your knee causes the meniscus to tear.

  • Patellar Instability

    Patellar Instability

    Any damage to the supporting ligaments may cause the patella to slip out of the groove either partially (subluxation) or completely (dislocation).

Knee Procedures

  • Total Knee Replacement

    Total Knee Replacement

    It is a surgery to replace diseased or damaged knee joint with an artificial knee joint made of materials, such as metal orplastics.

  • Revision Knee Replacement

    Revision Knee Replacement

    Revision knee replacement surgery involves replacing a part or all your previous knee prosthesis with a new prosthesis.

  • Unicompartmental/Partial Knee Replacement

    Unicompartmental Knee Replacement

    It is a minimally invasive surgery in which only the damaged compartment of the knee is replaced with an implant. It is also called a partial knee replacement.

  • Knee Implants

    Knee Implants

    Knee implants are artificial devices that form the essential parts of the knee during a knee replacement surgery. The knee implants vary by size, shape, and material.

  • Correction of a Failed Knee Replacement

    Correction of a Failed Knee Replacement

    Reoperation of a total knee replacement to resolve a painful knee condition and loss of motion arising out of a damaged or worn out prosthesis

  • Correction of a Loose Knee Replacement

    Correction of a Loose Knee Replacement

    Reoperation of a total knee replacement to correct a loosened prosthesis as a result of wear and tear of the prosthetic joint surfaces is known as correction of a loose knee replacement.

  • Correction of a Painful Knee Replacement

    Correction of a Painful Knee Replacement

    Reoperation of a total knee replacement to correct a loosened prosthesis as a result of wear and tear of the prosthetic joint surfaces is known as Correction of a Painful Knee Replacement.

  • Meniscal Surgery

    Meniscal Surgery

    Meniscal surgery is a surgical procedure employed for the treatment of torn or damaged meniscal tissues in the knee. It is mostly performed as a minimally invasive keyhole procedure.

  • Quadriceps Tendon Repair

    Quadriceps Tendon Repair

    Quadriceps tendon is a thick tissue located at the top of the kneecap. The quadriceps tendon works together with the quadriceps muscles to allow us to straighten our leg.