KNEE ANATOMY

The knee is a complex joint made up of different structures including bones, tendons, ligaments and muscles. They all work together to maintain 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 thigh-bone (femur) and the shinbone (tibia). There are two round knobs at the end of the femur called femoral condyles which articulate with the flat surface of the tibia called the tibial plateau. The tibia plateau on the inside of the leg is called the medial tibial plateau, and on the outside of the leg it is called 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 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 which 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, there 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 by preventing 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 function to stabilize the knee joint. There are two important groups of ligaments that hold the bones of the knee joint together, collateral ligaments and the cruciate ligament.

Collateral ligaments are present on either side of the knee. They function to 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 or ACL and the cruciate ligament in the back of the knee is called posterior cruciate ligament or PCL.

Muscles of the Knee

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

Tendons of the knee

Tendons are structures that attach muscles to the 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.

ACL Tears

What is the ACL? The anterior cruciate ligament, or ACL, is one of the major ligaments of the knee...

Meniscal Tears

What is a Meniscal Tear? Meniscus tear is the commonest knee injury in athletes, especially those...

Runner’s Knee

What is runner's knee? Patellofemoral pain syndrome also called runner's knee refers to pain under...

Runner’s Knee

What is runner's knee? Patellofemoral pain syndrome also called runner's knee refers to pain under...

Meniscal Tears

What is a Meniscal Tear? Meniscus tear is the commonest knee injury in athletes, especially those...

ACL Tears

What is the ACL? The anterior cruciate ligament, or ACL, is one of the major ligaments of the knee...

Meniscal Tears

What is a Meniscal Tear? Meniscus tear is the commonest knee injury in athletes, especially those...

ACL Tears

What is the ACL? The anterior cruciate ligament, or ACL, is one of the major ligaments of the knee...

Unicondylar Knee Replacement

What is Unicondylar Knee Replacement? Unicondylar knee replacement 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. The knee can be divided into three...

Total Knee Replacement

What is Total Knee Joint Replacement? Total knee replacement, also called total knee arthroplasty, is a surgical procedure in which the worn out or damaged surfaces of the knee joint are removed and replaced with artificial parts. What is Arthritis? The knee is made...

Revision Knee Replacement

What is Revision Knee Replacement? Revision knee replacement surgery involves replacing part or all your previous knee prosthesis with a new prosthesis. Although total knee replacement surgery is successful, sometimes the procedure can fail due to various reasons and...

Knee Arthroscopy

Knee Anatomy The knee joint is one of the most complex joints of the body. The lower end of the thighbone (femur) meets the upper end of the shinbone (tibia) at the knee joint. A small bone called the patella (kneecap) rests on a groove on the front side of the...

ACL Reconstruction – Patellar Tendon

What is ACL Reconstruction Patellar Tendon Method? Anterior cruciate ligament (ACL) reconstruction patellar tendon is a surgical procedure that replaces the injured ACL with a patellar tendon. Anterior cruciate ligament is one of the four major ligaments of the knee...

ACL Reconstruction – Hamstring Tendon

 Anterior Cruciate Ligament Tears The anterior cruciate ligament is one of the major stabilizing ligaments in the knee. It is a strong rope- like structure located in the center of the knee running from the femur to the tibia. When this ligament tears...

ACL Reconstruction

What is ACL Reconstruction? ACL reconstruction is a commonly performed surgical procedure and with recent advances in arthroscopic surgery can now be performed with minimal incision and low complication rates. The advancements in arthroscopic surgery make it easy for...

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