If you missed part 1, you can see it here.
Anatomy of the Knee cont.
Next to the femur, the tibia is the largest bone in the body. It is the weight bearing bone of the lower leg. The upper end of the tibia joins with the femur and its lower end joins with the talus, the bone that forms the lower part of the ankle. The fibula is located on the outer side of the leg. Unlike the tibia, this bone is non-weight bearing. Instead, it functions as an ankle joint stabilizer and as an attachment site for one of the four major knee ligaments and the biceps femoris tendon. The lower end of the fibula protrudes on the lateral side of the ankle.
The patella, also known as the kneecap, protects the knee joint. It holds the quadriceps tendon on the lower end of the femur, acting as a fulcrum for the quadriceps muscles. The quadriceps is a group of four individual muscles on the anterior part of the thigh. The lower patella connects to the tibia through the patellar tendon.
Incompletely covering the surface of the tibia that joins with the femur are the C-shaped fibrocartilages known as the medial and lateral menisci. The menisci function as shock absorbers that equally spread the weight of the body, reducing friction between the tibia and the femur during knee movements. They assist in knee rotation and play a function in stabilizing the ligaments.
Most areas of the menisci are not supplied by blood, which contains oxygen and nutrients needed for healing. When these structures are damaged, repair is nearly impossible. The menisci deteriorate with age. Menisci damage is a common cause of knee pain and injuries.
Knee Joint Capsule
The knee capsule is a thick, water-tight sac that surrounds the knee joint. The outer part of the capsule is lined with a fibrous and thick membrane. Within the capsule is the synovial membrane, which produces the fluid that lubricates the joints. This fluid also provides nutrients to the articular cartilage.
The movements and the stabilization of the knee joint are supported by the quadriceps and the hamstrings. The quadriceps is actually composed of four individual muscles located on the anterior upper leg. These muscles are the vastus lateralis, vastus medialis, vastus intermedius and rectus femoris. These muscles fuse, forming the quadriceps tendon. The quadriceps straightens the knee by pulling the patella up on contraction.
The hamstrings are the muscles that attach to the tibia, specifically at the back of the knee. It consists of three individual muscles: biceps femoris, semitendinosus and semimembranosus. The hamstrings functions by flexing or bending the knee joint. This muscle group also provides stability on both sides of the knee.
That is the end of Part 2. I will have part 3 up very soon.
If you are interested in knee pain, knee injuries or ACL injuries, these other posts may interest you:
If you are looking for stuff with more details on knee pain and ACL injuries, you can attend the live course called Exercise Rehabilitation of the Knee or instantly download my video presentation on Exercises for Prevention, Rehabilitation and Overcoming Knee Injuries.
Rick Kaselj, MS