[Ultrasound documentation of translational movement of the shoulder joint. Normal values and pathologic findings].

In a prospective study we evaluated diagnostic ultrasound investigation for shoulder instabilities. In 150 healthy persons we measured the passive ap-translation in relation to the dorsal glenoid as well as the inferior subluxation in relation to the acromion. After establishing normative data we measured 23 patients with unidirectional instabilities and 34 with multidirectional instabilities. The humeral head position of a normal joint is 8 to 10 mm dorsally to the glenoid. In the control group, the anterior translation of the dominant shoulder (Student-t test p = 0.0045) was significantly higher. Patients with anterior instabilities showed a significant increase of anterior translation in the injured shoulder (Student-T test; p = 0.0001). In comparison to the control group, there is a significant increase in downward subluxation in patients with multidirectional instabilities (chi2, alpha = 0.05). In habitual or voluntary dislocations, the relation of the humeral head to the glenoid can be judged statically and dynamically. Secondary signs of dislocation (Hill-Sachs lesions, joint effusion) are evident.