What joints do a person have? How the joint works: anatomy, scheme. Types of joints by structure, shape, movement: Description

The joints are the main element of the human body, without which it would be impossible to move. Let's find out how the joints are arranged and what they are.

Joints are the basis of all body movements. If they were not there, then a person could not move. They are in every bone of the body, and in structure they look like hinges. This allows them to move smoothly without friction and not collapse. The joint is a combination of two or more bones. They differ in varying degrees of mobility, as well as functions and other features. Let's talk in detail about how the joints are arranged and how they differ.

How the joints of a person are arranged: elements

The joint is a two -layer “bag”. It connects several bones together. Due to the bag, the articular cavity becomes hermetic and can easily produce a synovial fluid. The latter is responsible for the normal depreciation of bones. This all allows us to ensure the performance of three most important functions: stabilize the location of the body, navigate in space and move.

Joints are distinguished by a complex structure from:

• Cavities. This is free space in the walls of the joint, filled with synovial fluid.
• Capsules. This is a connective tissue covering the joint from above. The capsule itself is covered with a fibrous membrane, and inside it is synovial. Actually, the corresponding liquid is produced from the latter.
• Joint surface. It differs in different forms, depending on the type of connection. One side is usually convex and resembles the head, and the second looks like a hole. This provides a better connection.
• Synovial fluid. This substance is designed to moisturize the surface of the joint so that there is no friction in the joints and it does not collapse.
• Cartilage fabric. From above, the bone is always covered with cartilage. He is responsible for the depreciation and helps to move smoothly. It consists of connective tissue complemented by synovial fluid.
• Ligaments and muscles. These are auxiliary elements, but without them movements are impossible. The ligaments allow you to fix the bones and they always remain in one place.
• Bone protrusions. The function of these elements is that they limit the amplitude of movements. If it were not, then we would go very funny if we could do it at all. For example, in the shoulder joint they reduce the range of the wave of the hand.

What are the joints of building, shape, nature of movement: types, classification

During the evolution, a person constantly changed. The movements became more and more and the body adjusted for it. This led to the development of the joints. To date, they have an extensive classification.

By structure

This group divides the joints by the number of bones connected in them. So, they are:

• Simple - two bones are connected (fingers).
• Complex - The compound includes more than two bones (elbow).
• Complex - These are two -chamber joints with cartilary. They connect one or more joints. For example, it can be the lower jaw. The compounds can be completely or partially separated. In the first case, this is a disk shape, and in the second - a minisk in the knee.
• Combined. Such joints are placed independently of each other.

The joints also differ in shape, it immediately becomes clear if you take two different connections and look at them. They are:

• Sherrovid. One part of the connection of such a joint looks like a ball, and the second, as it were, holds it and has a concentrated look.
• Ellipsoid. Outwardly, they resemble Ellips.
• Small. Joints like taps look like. An example is the knee.
• Sades. Judging by the name, it is already clear how they look. Somewhat their view resembles a saddle. The temporal-melting joint is a bright representative of this type.
• Cylindrical. They differ in the surface similar to the cylinder. At the same time, one part is convex, and the second is concave.
• Blocks. Another group of joints with deepening and protrusion. For example, finger phalanges.
• Flat. Compounds of such joints are ideal for each other. They are not very mobile. For example, such is the sacral and illegal joint.

Each joint can move differently, and may not move at all. Therefore, one more classification can be distinguished - according to the type of movement:

• Multi -axial. Movement is possible in various directions. The most mobile of all is considered the shoulder joint.
• Double. Movement is allowed in two axes. For example, bending, extensions of the arms and legs.
• Blessed. Such joints do not have the possibility of rotation. In this case, the bones simply slide on each other. For example, a bright -language bone can be considered a bright representative, which is almost motionless.
• Combined. These joints can work together and are capable of many movements. For example, this is a carpal joint.

Now let's talk in detail about how different joints of the human body are arranged.

Knee joint - structure, functions: scheme

The knee joint, according to the classification, is a complex block. It connects the knee cup and a large bone bone.

It consists of cartilage on the surface, and the capsule resembles a bag where the bone connection is hidden. Its top is covered with a synovial shell inside which is a liquid. Its composition is similar to blood plasma, but there are not many proteins in it and there are unique substances.

Among other things, in the articular cavity there are meniscus, similar to sickle cartilage. They provide a knee with a good depreciation.

It is important to note that the knees are in good mobility and this is possible thanks to the fabrics located near them. These are muscles, tendons, vessels and so on. All of them continuously work and provide the knee with everything necessary.

The knee joint is considered the largest and it can bend, bend or even rotate in a circle.

Shoulder joint - structure, functions: scheme

The shoulders are considered the most mobile part of the skeleton. They are able to move in different axes due to the spherical connection of the joint itself consists of three elements - the shoulder and scapular bone, as well as the articular capsule connecting them.

The movements of the shoulder joint are stabilized and reliable due to a reliable frame of muscles. Plus, it does not allow muscles to shift and they are always in one place. The shoulders usually move in three axes:

• Frontal. Allows you to bend and unbend the joint
• Saggital. This axis is responsible for the discharge and summing up
• Vertical. With its help, rotation is ensured

When the movement flows into another axis, a circular rotation is obtained. Human hands in terms of movements are not too limited and this is possible thanks to shoulders.

Hip joint - structure, functions: scheme

This is another spherical joint. Although he can move in three directions, these movements are very limited. It has a strong frame of muscles and ligaments, since he has to experience very large loads.

The hip joint is formed by the joint of the femur and the acetabulum. The joint capsule is fixed on epiphysis, and the rest of the surface is covered with a synovial membrane.

The swivel lip, as it were, is a continuation of the hollow and, located in the joint cavity, makes it deeper. Such a structure, something like a bowl.

Wrist joint - structure, functions: scheme

It has a very complex structure. It is important to note that it can be compared with complexity, except that the spine. In the wrist joint, different types of bones are connected and there are a lot of them. Moreover, here the wrist and brush are connected to each other.

It is important to note that the bones here do not always contact a friend. In this case, the ligamentous apparatus connects them together and the hand with great functionality is formed. If we take into account how the bone connection occurs, then we can talk about the possibility of their movement in different directions, but at the same time they will be limited.

Ankle joint - structure, functions: scheme

The block joint formed by a large and small bervice. In addition, they are still connected to the surface of the rambone.

Each compound is securely strengthened by a frame of ligaments and tendons. The fact is that they are the greatest load of all and they need to be mobile. The bone connection is similar to the fork, and the foggy bones seem to adhere to.

The top of the bones is covered with hyaline cartilage. The joint is located in the bag and strengthened by ligaments. The maximum joint amplitude of the joint is 50-70 degrees. In exceptional cases, it can reach 90 degrees.

Video: joints, structure, functions