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Knee Anatomy

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.

ACL Tears

ACL Tears

The anterior cruciate ligament (ACL) is one of the major ligaments of the knee. It is located in the middle of the knee and runs from the femur (thighbone) to the tibia (shinbone).

Patellofemoral Instability

Patellofemoral Instability

Patellofemoral instability means that the patella (kneecap) moves out of its normal pattern of alignment.

Meniscal Injuries

Meniscal Injuries

Meniscal tears are among the commonest injuries to the knee joint. It can occur at any age but are more common in athletes involved in contact sports.

Knee Procedures

Total Knee Replacement

Total Knee 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 an artificial prosthesis.

Unicompartmental/Partial Knee Replacement

Unicompartmental/Partial Knee Replacement

Unicompartmental knee replacement is a minimally invasive surgery in which only the damaged compartment of the knee is replaced with an implant.

Knee Arthroscopy

Knee Arthroscopy

Knee arthroscopy is a common surgical procedure performed using an arthroscope, a viewing instrument, to diagnose or treat a knee problem.

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.

Arthroscopic Reconstruction of the Knee for Ligament Injuries

Arthroscopic Reconstruction of the Knee for Ligament Injuries

Arthroscopic knee ligament reconstruction is a surgical procedure to correct a torn knee ligament by replacing the ligament with a healthy tendon tissue using an arthroscope.

Cartilage Replacement

Cartilage Replacement

Cartilage replacement is a surgical procedure performed to replace the worn-out cartilage with new cartilage.

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