Our knee is the most complicated and largest joint in our body. It’s also the most vulnerable because it bear enormous weight and pressure loads while providing flexible movement. When we walk our knees support one and a half times our body weight. With climbing stairs, our knees support between three and four times our body weight. With squatting our knees support eight times our body weight.
The knee joint connects the femur and thigh bone to the tibia. There are two joints in the knee:
- The tibiofemoral joint, which joins the tibia to the femur, and
- The patellofemoral joint which joins the kneecap to the femur
These two joints work together to form a modified hinge joint that not only allows the knee to bend as well as straighten but also to rotate slightly in addition to from side to side.
The knee joint carries the majority of a person’s body weight. When we’re sitting the tibia and femur hardly touch. Standing they lock together in order to form a stable unit. Let’s look at a normal knee joint in order to understand how the parts (anatomy) work together.
The anatomy of the knee
Anatomical terms allow us to explain the body clearly and precisely using planes, areas and lines. Instead of your doctor saying “his knee hurts” they can say “his knee hurts in the anterolateral region” and another doctor will know exactly what is meant.
Below are some anatomical that orthopaedic surgeons use that apply to the knee:
- Anterior: facing the knee this is the front of the knee
- Posterior: facing the knee this is the back of the joint and is also used to describe the back of the kneecap, in other words, the side of the kneecap that is next to the femur
- Medial: the side of the knee that is closest to the other knee so if you put your knees together the medial side of each would touch
- Lateral: the side of the knee that is farthest from the other knee (opposite of the medial side)
Structures of the body often have their anatomical reference as part of their name.
Structure of the knee
The main parts of the knee joints are:
- Cartilage, and
- A joint capsule.
Collagen is a fibrous tissue that is present throughout our body. As we age, collagen breaks down.
The adult skeleton is mainly made up of bone and a little cartilage in places. Bone and cartilage are both connective tissues with specialised cells called chondrocytes embedded in a gel-like matrix of collagen and elastin fibres. Cartilage can be hyaline, fibrocartilage and elastic, and differs based on the proportions of collagen and elastin.
In addition, cartilage is a stiff but flexible tissue that is good with weight-bearing which is why it is found in our joints. This substance has almost no blood vessels and is very bad at repairing itself. Bone is full of blood vessels and is very good at self-repair. It is the high water content that makes cartilage flexible.
The knee is a complicated structure as well as one of the most stressed joints which are present in the body. It is the biggest joint, essential for movement, and vulnerable to injury. Keeping strong, flexible leg muscles and getting prompt medical attention for all knee injuries is essential to assure an accurate diagnosis and proper treatment of the injury. In addition, keeping the supporting leg muscles strong and practising injury prevention will help keep the knee healthy during a person’s lifespan.
Want to know more regarding the anatomy of other parts of your body? If so then you need to do our Exercise Science Course. For more information, please follow this link.