Basic Study Of The Sternoclavicular Joint

The sternoclavicular joint(SCJ) is covered with many ligaments around, only the powerful force can destroy the ligaments and cause dislocation. Traffic accident and sports injury are the main reasons of SCJ dislocation. The sorts of SCJ dislocation consist of anterior dislocation and posterior dislocation, which depend on the relative position of manubrium and sternal hand. Either direct or indirect force can produce a dislocation of the SCJ. When a force is applied directly to the sternal hand, the clavicle is pushed posteriorly behind the sternum and posterior dislocation occured. The force can be also applied indirectly to the sternoclavicular joint from the anterolateral or posterolateral aspects of the shoulder. Energy transmitted to SCJ though the clavicle and loaded posterior or anterior dislocation. The SCJ dislocation, especially the posterior dislocation, seriously affects the people's living standard. But the epidemiological study and imageological measurement of SCJ are seldom reported. Therefore, PACS system and case reports checking system were used to collect and analyse the data of patients with SCJ dislocation, and 50 normal SCJ computed tomography(CT) images were also selected to quantified the anatomic relationship between the sternum and the underlying structures.Part 1 The epidemiological analysis of the dislocation of sternoclavicular jointObjective To investigate the epidemiological features of patients with dislocation of sternoclavicular joint treated in our hospital between 2003 and 2010.Methods The data of patients with dislocation of sternoclavicular joint was collected and analyzed through the PACS system and case reports checking system. The issues include gender, age, injured sites, type of dislocation, and complications.Results 52 patients with dislocation of sternoclavicular joint including 36 males and 16 females were selected. There are 18 cases with left sternoclavicular joint dislocated and 34 cases with right. The high risk ages of all patients are between 20 and 60 years, and the aged over 60 have lower morbidity. 9 cases were subluxation and 43 cases were complete dislocation. The complete dislocation is the common type. 20 cases were posterior dislocation and 32 cases were anterior dislocation, which is more common including 19 males and 13 females. During these 52 patients, 20 cases were admitted to our hospital (12 for surgery and 8 for conservative treatment), and bone plate is the more common used than Kirschner wire to fix the sternoclavicular joint.Conclusion This investigation implied epidemiological features of dislocation of sternoclavicular joint between 2003～2010 in our hospital.Part 2 The CT study of sternoclavicular jointObjective To investigate the anatomical feature of the sternoclavicular joint and determine the safe drilling direction and depth in the sternoclavicular region.Methods Computed tomography(CT) scans were taken on 50 healthy subjects. Reconstructive images on coronal, sagittal and transverse planes of the sternoclavicular region, from the superior border of the clavicle to sternal angle, were obtained. Measurements including the height and anteroposterior dimension of proximal end of clavicle, the length and anteroposterior dimension of clavicular notch, the angle between clavicular notch and sternum, the angle between manubrium sterni and trunk, the thickness of manubrium sterni and the distance between the bilateral clavicles were performed on these images.Result Measurements on the coronal images demonstrate that the angle between clavicular notch and sternum is different among the individuals and the proximal end of clavicular is higher than the manubrium sterni. The transverse images reveal that anteroposterior dimension of proximal end of clavicle is longer than the clavicular notch and the center of the manubrium sterni is much thicker than edges. Among the tissues behind the sternum, anonyma and bilateral innominate veins are nearest to the manubrium sterni.Conclusion Different dimensions of the sternoclavicular joint were measured on the CT images which could help the diagnosis and treatment of sternoclavicular dislocation.