Joints

  • Knee joint
  • Ankle joint
  • Shoulder joint
  • Elbow
  • Wrist joint
  • Loose joints
  • Diseases and injuries of joints
  • Tips for strengthening of joints
  • The joint - mobile compounds of the bones of the skeleton with the presence of a gap between the articulated bones. The joint is one of the types of articulation bones; another type joint - continuous connection bones (without joint space) - bears the name of sinanthropa. The joints are running both support and motor functions.

    structure of the joint Fig. 1. Structure of joint : 1 - articular cartilage; 2 - fibrous sheath joint capsule; 3 - synovium; 4 - the joint cavity; 5 - ends articulated bones (epiphyses); 6 - periosteum.

    Fig. 2. Types of joints of the hand:
    1 - ellipsoidal;
    2 - saddle;
    3 - spherical;
    4 - bokoviny.

    The main elements of the joint are articulate surfaces (ends) connects bones and joints, bags lined the inside of the synovial membrane (see), and joint cavity (Fig. 1). In addition to these basic elements that make up the joint, there are more and secondary education (ligaments, discs, menisci and sinovialnuu bag), occurring not in all joints.
    The ends of the articulated bones (epiphyses) constitute a firm basis of joint and due to its structure can withstand heavy loads. Hyaline cartilage thickness of 0.5-2 mm, covering the articular surfaces and very closely connected with the bone, provides better fit to the ends of the bones in motion and acts as a shock absorber in the bearing joints.
    Joint bag closes the joint cavity, catching the edges of the articular surfaces of connecting bones. The thickness of this capsules different. In some joints it tight, others are free. In the capsule there are two layers: the inner synovial and outer fibrous, consisting of dense connective tissue. In some places of the fibrous layer forms a thickening - ligaments (see). Along with bundles that are part of the capsule, in strengthening of joints involved and cartilage and synovial joints. Joints further strengthened through the muscles and tendons.
    Articular cavity in the form of cracks contains a small amount of synovial fluid that produces synovial membrane and is a transparent viscous liquid of yellowish color. It serves as a lubricant joint surfaces, reducing the friction movements in the joints.
    Auxiliary staff of the joint along with a bunch of presents articular cartilage (meniscus, disks, joint lip), which, lying between the articular ends of the bones or on the edge joint, increase the contact area of the epiphyses, make them more appropriate to each other and play a big role in the mobility of joints.
    The blood supply of the joints occurs at the expense of the branches nearest arteries; they articular capsule form a dense network communications. The outflow of blood is rushing through my veins in adjacent venous trunks. Lymph drainage is carried out through the network of small lymph vessels in the next lymphatic collectors.
    Innervation of the joints is provided and spinal sympathetic nerves.
    The function of the joints is determined mainly by shape of the articulated surfaces epiphyses bones. Articular surface of a bone is like an imprint of another, in most cases one surface is convex - articular head, and the other concave - articular cavity. These surfaces are not always fully consistent with each other, often head has a large curvature and breadth than depression.
    If in the formation of the joint involved two bones, the joint call is simple; if more bones - complex.
    In the form of articulate surfaces of bones compared with geometric shapes and accordingly there are joints: spherical, ellipsoidal, bokoviny, saddle-shaped, cylindrical and other Movements can be carried out around one, two and three axes, forming one (cylindrical and bokoviny), two- (ellipsoidal and saddle) and multi-axis (spherical) joints (Fig. 2). The number and position of axles determine the nature of the movements. There are movements around the front axle bending and straightening, sagittal axis - casting and the abduction of, the longitudinal axis of rotation and multi-axis rotary motion.