Types Of Synovial Joints

Synovial joints create a connection between two bones. They consist of a cavity lined with cartilage and filled with fluid. In this article, we will take a closer look at what these joints are, where they are located and their function.

Characteristics of synovial joints

First  , all joints have a layer of cartilage that covers the articular surfaces of skeletal elements. The surface of the bones is therefore not in direct contact with each other. When these joints are visible on X-ray, there seems to be plenty of space between adjacent bones.

The second characteristic of synovial joints is the presence of an articular capsule. It basically consists of an inner synovial membrane and an outer fibrous membrane.

The synovial membrane

This membrane covers the inner surface of capsules in synovial joints and tendon sheaths. It generally creates contact with the fibrous membrane and the synovial liquid lubricant.

Closed synovial membrane sacs also appear on the outside of the joints. This is where they form bursae or tendon sheaths. The sacs often form between the structures such as tendons and joints, tendons and bones or skin and bones, and reduce friction when one structure moves over another. Tendon sheaths also surround tendons and reduce friction.

The fibrous membrane

The fibrous membrane consists of dense irregular connective tissue. It  surrounds and stabilizes the overall lead.

Parts of the fibrous membrane may become thicker to form ligaments, which further stabilize the joint. The ligaments, which are located on the outside of capsules, often provide additional support.

Other characteristic structures of synovial joints

Another characteristic of synovial joints is the  presence of additional structures  within the area covered by the synovial membrane. These include:

• Articular discs. These usually consist of cartilage. They absorb compressive strengths, adapt to changes in the surface of the joints during movements and increase the amount of movement that can occur in the joints.
• Articular fat pads. These are often located between the synovial membrane and the capsule. They also penetrate and leave these areas as the articular contour changes during movements.

Types of synovial joints

The body has the following types of synovial joints:

1. Glideled. These generally allow sliding movements when one bone moves over another. An example is the acromioclavicular joint, which is located at the top of the shoulder.
2. Hinge joints  are joints that allow you to bend and stretch a hinge. An example is the elbow.
3. Swivel joints  allow movement about an axis, which means they regulate rotational movements. An example is the connection between the spool bone and the elbow bone of the arms.
4. Compound or bicondyloid joints. These joints allow movement between one axis with limited rotation about another axis. They consist of two convex bones. An example of this type of joint is the knee.
5. Condyloid joints  allow movement within two perpendicular and passive or secondary movements on a third axis. They therefore allow movements with bends, stretches, to lead things away and towards themselves. This is the case with the  joint in the wrist.
6. Sadelled. These allow the same movements as the condolyoid joints, but allow greater movement. This name derives from their shape as a saddle. They provide the ability to bend, stretch, lead in and lead out.
7. Ball joints  allow all movements except to slide. They allow for movements where one bends, stretches, leads out and leads in. The hip is an example of this type of joint.

Conclusion

If we did not have joints, the bones in our bodies could not move. Thanks to our joints, we can make various movements such as bending down, rotating and bending our arms and legs!