Joints are fundamental structures in the human body that allow the union between two or more bones, facilitating the mobility and functions of the musculoskeletal system. Within the classification of joints, we find diarthroses, also known as synovial joints, which have particular anatomical characteristics that distinguish them from other types of joints.
Definition and Function of Diarthroses
Diarthroses are a type of synovial joint that is characterized by presenting a joint cavity that contains synovial fluid, which allows a wide range of movement between the bones that make them up. These joints are the most complex in terms of structure and function, since they allow movements such as flexion, extension, abduction, adduction, circumduction and rotation.
The main function of diarthroses is to provide stability to the joints and allow smooth and coordinated movements, which is essential for everyday activities such as walking, running, lifting objects, among others. In addition, these joints contribute to the proper distribution of the load during movement, thus protecting the bones and soft tissues from possible injuries.
Types of Diarthrosis
There are several types of diarthrosis, classified according to the way the bones are joined and the type of movement they allow. Below are some of the most common types:
1. Enarthrosis joints
Enarthrosis joints, also known as ball and socket joints, are those in which a rounded surface of one bone fits into a concave cavity of the other bone. This type of diarthrosis allows movements in all directions, such as the hip and shoulder.
2. Trochlear joints
In trochlear joints, a bone with a cylindrical or elongated shape fits into a pulley-shaped cavity in the other bone. An example of a trochlear joint is the knee joint, which allows flexion and extension of the leg.
3. Ginglimus joints
Ginglimus joints, also known as hinge joints, are those in which a pivot-shaped bone meets a concave surface of the other bone, limiting movement to a single direction . An example of a ginglimus joint is the elbow joint.
4. Condylar joints
In condylar joints, two condyles of one bone articulate with two corresponding cavities in the other bone. This type of diarthrosis allows flexion, extension and certain rotation movements, as in the jaw joint.
Anatomical Characteristics of Diarthrosis
In addition to the different types of diarthrosis according to the form of union of bones, these joints have specific anatomical characteristics that distinguish them from other types of joints in the human body. Some of these characteristics are:
1. Presence of Joint Cavity:Diarthroses present a joint cavity that contains synovial fluid, which acts as a lubricant to reduce friction and facilitate bone movement.
2. Articular Cartilage:In the articular surfaces of the bones that make up a diarthrosis, articular cartilage is present, a resistant and elastic tissue that helps cushion impacts and evenly distribute the load during movement.
3. Synovial Membrane:Diarthroses are covered by a synovial membrane, which is responsible for secreting synovial fluid and keeping the joint lubricated. This membrane also contributes to the nutrition of the joint structures.
4. Articular Ligaments:To provide stability to the joint, diarthroses have articular ligaments, fibrous structures that connect the bones to each other and prevent excessive or out-of-range movements.
5. Joint Capsule:The joint capsule surrounds the joint and is made up of tough fibrous tissue. This capsule protects the joint and maintains the integrity of the joint cavity.
Conclusion
In summary, diarthroses are a key type of synovial joint in the human body, allowing wide range of motion and contribute to the functionality of our musculoskeletal system. Knowing the types and anatomical characteristics of diarthroses is essential to understand their importance in the biomechanics of the body and in the prevention of joint injuries. Maintaining the health and proper functioning of diarthrosis is essential to enjoy a good quality of life and maintain mobility at all stages of life.