Athletes in all sports today are bigger, stronger and faster than ever before.
They also have access to better technology and training methods. One has only to watch a game of American football or Rugby Union to see the size and athleticism of the modern athlete compared to 20 years ago.
Knowledge to enhance gains
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The purpose of this article is to demonstrate how understanding the anatomy of the knee can lead to enhanced gains and prevention of injury.
Our joints haven’t evolved much over the last few thousand years, so I’m going to spare you blood supply, nerves, cells, fat pads, etc. and focus primarily on structures to give you a better understanding of the anatomy of the knee.
Netter illustrates the knee as being a gliding hinge joint; articulating on the head of the tibia and being supported with cartilage, ligaments, tendons and muscles.
The four bones that make up the knee joint are the Femur, Tibia, Fibula and superficial to those, the patella.
The largest bone in your body. It articulates (begins) at your hip socket and rests on the head of the tibia. The femur has condyles which is a rounded projection on the bone, usually for articulation with another bone.
In this case it would articulate with the tibial intercondyles (or grooves) to allow for the hinge movement.
Protects your knee and connects your quadriceps to your tibia. The ends of the femur and the undersides of the patella are covered with a slippery substance called articular cartilage. This helps the bones glide smoothly along each other as you move your leg.
There are several ligaments of the knee but I will focus on these four:
– Lateral collateral ligament
The lateral collateral ligament (LCL) goes from the top part of the fibula (the bone on the outside of the lower leg) to the outside of the lower femur. The ligament helps keep the outer side of the knee joint stable. It’s there to prevent your femur from sliding off the lateral (outside) of the tibia.
– Medial collateral ligament
The medial collateral ligament (MCL) goes from the inside surface of the upper tibia to the inner surface of the bottom femur. The ligament helps keep the inside portion of the knee joint stable. The MCL prevents your knee from buckling medially (inwards)
The posterior cruciate ligament (PCL) is the strongest ligament in the knee. It extends from the top-rear surface of the tibia to the bottom-front surface of the femur. The ligament prevents the knee joint from posterior instability.
This means it prevents the tibia from moving too much and sliding behind the femur.
– Anterior cruciate ligament
The ACL provides up to 86% of the restraint to anterior translation of the tibia on the femur (preventing the femur from moving too far ahead of the tibia); therefore, much research has been focused on this structure.
Netter illustrates that the ligament extends from the posterior medial side of the lateral femoral condyle to the anterior intercondylar area of the tibia. When you hear of a severe knee injury, the ACL is usually involved.
– Medial and lateral meniscus
The meniscus are a fibrocartilage attached to the tibial fossa and acts as a cushion for the knee.
Muscles and tendons
The muscles in the leg cross multiple joints but due to space constraints, we’ll focus on what they do to the knee.
The tendons of the vastus lateralis and medialis run parallel to and connect into the patella. Think of the patella as a pulley. The quadriceps connects to the near end of the patella with the patellar tendon connecting to the tibia (tibial tuberosity to be specific).
As you engage your quads, it pulls on the patella, which in turn cause the patellar tendon to pull on the tibia and engages the knee to extend. This allows you to walk, kick, etc.
The vastus medialis muscle plays a very important role in stabilizing the patella and knee during movement.
Your hamstrings originate in your hip region and connect into your tibia and fibula. They engage the knee to flex, along with internal and external rotation depending on which muscles are engaged.
It is generally agreed that between 15 and 60 degrees of flexion, the hamstring contraction is extremely important in reducing excessive forces exerted on the ACL. Meaning that they act as a braking system.
– Gastrocnemius and soleus
The gastrocnemius originate behind the knee on the femur and attaches via the achilles tendon on the heel. It acts as a stabilizer and flexor of the knee. The soleus muscle acts as a stabilizer and is most active when the knee is already flexed.
The knee plays a pivotal role in the body in regards to performance and daily activities. A muscle imbalance, muscle tightness or poor warms ups, all play a role in the health of the knee.
A good warm-up helps to release and circulate synovial fluid throughout the knee, allowing for lubrication and easier movement.
Having torn my ACL at one point (ironically after writing a paper on ACL tears), I realized that I was neglecting a very important piece to the machine that is our body. Take care of your joints and your joints will take care of you.
I hope the article gave you a better understanding of the anatomy of the knee.
Connect with Expert Paolo Busignani.