The sternoclavicular joint is not always clearly visible. It usually appears in people who are underweight or asthenics. In the presence of a small amount of subcutaneous fat, it can be considered. In people with normal or increased body weight, it is visually indistinguishable. On palpation, they are guided by the clavicle bones, between which, at the junction with the sternum, below the cervical fossa, there are two symmetrical sternoclavicular joints.
Definition and location of the joint
The sternum-clavicle is the junction of the clavicle with the sternum. It has an asymmetric shape, which allows you to compensate for the difference in size and shape of the bone cut and clavicle, allowing them to perfectly match each other. Inside the joint is the joint disk, which compensates for the pressure between the bones, as a connecting element. From above, the entire compound is covered with cartilage, protecting it from external influences and damage.
Sternum-clavicular joint. Characteristic
The purpose of the joint is to connect the upper limbs with the chest by combining the bones of the clavicle and shoulder girdle with the trunk. By its origin, the sternoclavicular joint is a rudiment, which is the connection of the upper or forelimbs not only in humans, but also in animals, starting with reptiles. He is very durable and participates in the movement of hands, the reformation. This is especially felt when raising hands up and down. This connection allows the clavicle to move along the three main axes, synchronizing with the shoulder joint, supported by a powerful and very strong ligamentous apparatus.
Structure
The sternoclavicular joint resembles a saddle-shaped joint in shape. In its structure, it has a communicating form, having concavities and bulges corresponding to each other. This joint, having two axes and freely moving along them, is a universal joint from the point of view of simple mechanics. Its structure includes such cartilage tissues:
- cartilaginous coating of the clavicle;
- cartilaginous coating of the sterno-costal cavity;
- cartilaginous disc;
- cartilaginous tissue covering the joint.
Thus, the structure of the joint includes:
- the medial end of the clavicle with its main surface;
- upper ligament;
- front ligament;
- ligament rib-clavicular;
- back ligament;
- concave arches of the sterno-costal surface.
The sternoclavicular joint is also supported by:
- The intervertebral ligament , stretching over the notch of the jugular cavity of the sternum between the ends of the clavicle.
- The complex of sternoclavicular ligaments . In their location, they converge on the front, back and upper surfaces of the joint, strengthening its strength.
- The most powerful and strong ligament in the sternum is the costal-clavicular . It passes from the very top edge at the first rib and rises to the collarbone. Controls the maximum lifting of the clavicle up.
The sternoclavicular joint, having a saddle-shaped structure, resembles spherical in the possibilities of its movement.
Damage
Due to its superficial location and role in the movements between the bones and joints of the shoulder girdle and trunk, the collarbone itself and the joints attached to it often undergo fractures and dislocations. Dislocation occurs as a result of sudden movements of the shoulder girdle posteriorly or downward and posteriorly. In this case, the anterior ligament breaks, forming a subluxation. With a stronger effect on this joint, all ligaments break, releasing the collarbone from the articular fossa, forming a dislocation of this joint, which is easily recognized by external signs. Another type of dislocation occurs if the impact on the collarbone and joint is direct, that is, by direct impact or strong pressure, when the posterior ligament breaks. Such a dislocation occurs inside the chest. It also happens when acting on the joint by tightly compressing the shoulders forward and inward. As a rule, with such effects, a fracture of the first or first four sternal ribs is also observed.
Diseases
This joint is characterized by diseases such as ankylosis, which is a consequence of gonococcal or rheumatoid arthritis. After the age of forty, an arthrosis disease often appears, which during its course forms marginal osteophytes on the head of the clavicle. Soreness caused by exposure to the sternoclavicular joint, crunch, swelling should be the reason for a visit to an osteopathic doctor.
Aseptic necrosis of the end of the clavicle attached to the sternum, which is better known as Friedrich's syndrome, is also determined by palpation. It causes a painful swelling of the tissues around the joint, edema and redness of the skin. Hyperostatic changes in the attached end of the clavicle are manifested in marble disease (Paget's disease). The manifestation of hyperostosis is typical for congenital syphilis.
Diagnosis of joint changes
Methods for the diagnosis of diseases and disorders in the sternoclavicular joint are examination and palpation, an x-ray of the chest bones. All studies are carried out by a traumatologist or osteopath. The presence of any asymmetry or deformation, redness or pain during movements in the sternoclavicular joint, the appearance of a crunch in movement indicate the presence of one of the above diseases or injuries.
Palpation is carried out by the second and third fingers of the right hand, while the doctor is located behind or on the side of the patient. The fingers are set in the middle of the sternum and, guided by the notch under the patient’s neck, feel for the joint. For better detection, his patient is asked to raise his hands in a horizontal plane, which greatly facilitates the search.
The sternum-clavicle joint is simple in structure. But at the same time he is quite strong, keeps the limbs attached to the body. With damage to this joint, arm movements become very limited and bring pain.