Anatomy of the Knee
The knee is the largest joint in the body that moves like a hinge, allowing you to sit, squat, walk or jump. The femur (thigh bone), tibia (shin bone), and patella (kneecap) make up the bones of the knee.
The bones in the knee are covered with a layer of cartilage that absorbs shocks and reduces friction allowing the bones to glide easily against each other. There are three types of cartilages: articular cartilage, the lateral meniscus and the medial meniscus.
The bones are held together and supported by four ligaments and one tendon. Quadriceps Tendon attaches the quadriceps to the patella. Medial Collateral Ligament (MCL) stabilizes the inner part of the knee. Lateral Collateral Ligament (LCL) stabilizes the outer part of the knee. Anterior Cruciate Ligament (ACL) prevents excessive forward movement of the tibia. Posterior Cruciate Ligament (PCL) prevents excessive backward shifting of the knee.
There are two groups of muscles that support the knee. Hamstrings run from the hip to just below the knee and work to bend the knee. Quadriceps run from the hip to the knee and straighten the knee from a bent position.
Prevalent Injury Areas
THE MOST COMMON INJURIES TO THE KNEE ARE:
1. Knee Fracture on Patella
2. Knee Dislocation
3. Knee Ligament Injury (torn ACL, PCL, MCL and LCL)
4. Meniscus Tear
5. Knee Tendon Tear
Causes of Injury & Symptoms
WHAT CAUSES INJURIES TO THESE AREAS (ABOVE) AND WHAT SYMPTOMS ARE EXPECTED?
1. Knee Fracture: When you fall or collide with an object very hard with your knee, your kneecap is first part of the knee that are susceptible to fractures.
2. Knee Dislocation: When there is a large impact to the knee such as fall and collision, kneecap can come out of its place. After first dislocation, moderate activities can cause the knee dislocation repeatedly.
3. Knee Ligament Injury (torn ACL, PCL, MCL and LCL): These common ligament injuries occur when the knee is overextended, or moved in a way it should not naturally move during various sports activities. If too much force was given, ligaments can stretch or tear.
4. Meniscus Tear: Meniscus injuries occur often during sports where jumping or twisting is involved. When athletes change direction quickly while running, meniscus can tear instantly.
5. Knee Tendon Tear: Landing awkwardly after coming down from the jump is a common way to injure the tendon, as the tendon is unable to support the overextension. Also, the tendon can be stretched due to the direct force to the front of the knee after the hard fall.
The two main signs of a knee injury are pain and swelling of the knee. Worse the injury, you will feel more pain and have greater degree of swelling in the knee. In addition, you may have difficulty with the joint moving, feel stiff, lock up, or feel like it's catching as you bend and straighten your let. If you hear your knee pop and then give out at the time of impact, it may be the sound of something tearing. You may feel like you can't stand firmly on your leg or your knee is giving way since your ligaments are unstable after the accident.