Parts of Knee - An Overview

Introduction

The knee is a complex joint that is the largest weight-bearing joint in the body. It consists of three parts: the femur (thigh bone), tibia (shin bone), and patella (kneecap). The kneecap helps protect the knee from wear and tear while providing a surface for ligaments and tendons to attach to the bones. The knee is made up of several different muscles, ligaments, and tendons that work together to allow the knee to move and bear weight. These components work together to provide stability and mobility, allowing us to perform everyday activities such as walking, running, and even climbing stairs.

What Are the Parts of the Knee?

The knee is a complex structure and one of the body's most stressed joints. It is the most significant joint, essential for movement, and prone to injury. It is made up of bones, menisci, ligaments, and tendons.

1. Bone: The knee joint consists of three bones called as

• Femur - It is an upper leg bone, also called the thigh bone.

• Tibia - It is a front lower leg bone or shin bone.

• Patella - Also known as the knee cap, is a small triangular-shaped bone that sits over the other bone at the front of the knee joint.

2. Cartilage: There are two types of cartilage in the knee joint

• Meniscus Cartilage: It is a C-shaped cartilage in the knee joint. It cushions between the thighbone (femur) and shinbone (tibia) and helps distribute body weight. They also contain nerves that help improve balance and stability. There are two types of the meniscus:

Medial - It is the largest of the two present on the inner side of the knee

Lateral- Present on the outer side of the knee

• Articular Cartilage: The articular cartilage covers the femur, top of the tibia, and back of patella bones at the end of the knee joint. It acts as a shock absorber and provides a smooth surface for movement.

3. Ligaments: Ligaments connect the bone to the bones. The four ligaments in the knee provide stability and hold the joint in place. These ligaments include:

• Anterior Cruciate Ligament (ACL) - It is located in the center of the knee. It prevents the femur from sliding backward on the tibia and the tibia from sliding forward on the femur.

• Posterior Cruciate Ligament (PCL) - It is also located in the center and prevents backward shifting of the knee.

• Medial Collateral Ligament (MCL) - It provides stability to the knee's inner part and prevents side-to-side movement of the femur.

• Lateral Collateral Ligament (LCL) - Provides stability to the outer part of the knee. It also prevents side movement of the femur.

4. Tendons: Tendons connect muscles and bones. The quadriceps tendon connects the front thigh muscles to the kneecap. The largest tendon in the knee is the patellar tendon which runs from the kneecap to the shinbone.

5. Muscles: Although muscles are not technically part of the knee joint, the hamstrings, and quadriceps are the muscles that strengthen the leg and aid in knee flexion.

• Hamstrings - There are three muscles at the back thigh that run from the hip to just below the knee and help to bend the knee.

• Quadriceps - Four muscle in front of the thigh that runs from the hip to below the knee. They help to straighten the knee joint.

• Gluteal - The gluteal muscles, also known as the glutes, are located in the buttocks and play an important role in knee positioning.

6. Joint Capsule: A joint capsule is a bag of membranes that surround the knee joint. It is filled with synovial fluid, a liquid that lubricates and nourishes the joint.

7. Bursa: Bursas are tiny fluid-filled sacs in the knee joint. They act as cushions between the bones and other structures, helping reduce friction and wear. The bursa in the knee can become inflamed from overuse or injury and cause pain and discomfort.

What Are the Symptoms Associated With Knee Problems?

The symptoms of knee problems vary depending on the condition. Common symptoms include :

• Pain - It may be localized to the knee or radiated down into the leg.

• Swelling - Swelling is usually more prominent in the morning and after activity.

• Stiffness- Stiffness is most often felt after sitting or lying down for an extended period.

• Locking or Catching - can occur when certain pieces of tissue within the knee are damaged, resulting in a temporary inability to straighten or bend the leg.

• Instability and Weakness - Instability or weakness can make walking or performing daily activities difficult. If a person experiences any of these symptoms, they must contact the doctor for diagnosis and treatment.

What Are the Some Common Knee Problems?

The knee is comprised of numerous vital structures, any of which can be injured. The following are some of the more common knee problems.

1. Chondromalacia: Also called Patellofemoral syndrome, This is a condition in which the cartilage on the underside of the kneecap becomes soft and starts to wear away. They can cause pain and swelling in the knee and grinding sensations when moving the knee.

2. Knee Osteoarthritis: This condition affects the joints of the knee, causing them to become stiff and painful. Symptoms include joint swelling, tenderness, stiffness, and difficulty moving the knee.

3. Knee Effusion: Fluid buildup inside the knee due to inflammation, arthritis, and injuries to the knee can cause knee effusion.

4. Meniscal Tear: This is an injury to one of the two rubbery discs between the knee's shin bone and thigh bone. Symptoms include pain, swelling, and locking or catching the knee joint.

5. ACL (Anterior Cruciate Ligament) Strain or Treat: The ACL is responsible for a large portion of the knee's stability. An ACL tear frequently results in the knee "giving out," which may necessitate surgical repair.

6. PCL (Posterior Cruciate Ligament) Strain or Tear: PCL tears can result in pain, swelling, and instability in the knee. These injuries are less common than ACL tears; physical therapy is usually preferable to surgery.

7. MCL (Medial Collateral Ligament) Strain or Tear: Injury to the MCL may cause pain and instability to the inner side of the knee.

8. Knee Bursitis: Knee bursitis is characterized by pain, swelling, and warmth in any knee bursae. Bursitis is frequently caused by overuse or injury.

9. Patellar Subluxation: The kneecap slides abnormally or dislocates along the thigh bone during the activity. As a result, there is knee pain around the kneecap.

10. Patellar Tendonitis: Tendon inflammation connects the kneecap (patella) to the shin bone. It is most common in athletes as a result of repeated jumping.

11. Rheumatoid Arthritis: An autoimmune disorder that can result in arthritis of any joint, including the knees, if left untreated, can cause permanent joint damage.

12. Baker’s Cyst: It is a fluid accumulation in the back of the knee. A persistent effusion in the condition of arthritis typically causes Baker's cysts.

13. Gout: A type of arthritis caused by the accumulation of uric acid crystals in a joint. The knees may be affected, resulting in severe pain and swelling.

14. Pseudogout: A type of arthritis similar to gout in which calcium pyrophosphate crystals deposit in the knee or other joints.

15. Septic Arthritis: An infection inside the knee caused by bacteria, viruses, or fungus may cause inflammation, pain, swelling, and difficulty moving the knee.

How to Prevent Knee Injuries?

Knee injuries are some of the most common types of sports injuries, and they can range from minor to severe. To avoid knee injuries, following a few simple safety steps is essential.

• Warm up properly before physical activity. Warming up increases blood flow to the muscles, which helps to prevent injuries.

• Stretching before and after exercise is also essential for loosening muscles and reducing strain on the knee joint.

• Maintain leg muscle strength by using the stairs, riding a stationary bicycle, or lifting weights.

• Avoid abrupt changes in exercise intensity.

• Maintain a healthy weight to avoid putting additional strain on the knees.

• Wear the seatbelt at all times and also wear knee guards.

In addition, proper footwear is essential for knee injury prevention. Shoes should fit correctly and provide adequate support. For more intense activities, such as running or playing sports, specialty shoes may be beneficial for additional shock absorption and cushioning.

Conclusion

The knee is a complex joint critical for mobility and stability. Know the parts, disorders, and injuries associated with the knee. Common knee disorders include osteoarthritis, tendonitis, and ligament tears. Prevention measures include proper form, wearing appropriate protective gear, and taking breaks. If a person experiences symptoms of knee problems, it is best to seek medical advice from a professional.