THE RELATION BETWEEN THE POSITION OF THE GLENOHUMERAL JOINT AND THE INTRAARTICULAR PRESSURE - AN EXPERIMENTAL-STUDY

Intraarticular pressures of the glenohumeral joint were measured in 15 cadaveric shoulders during passive movement of the humerus and under various inferiorly directed loads on the humerus. With a fiber-optic t ransducer-tipped catheter and an airtight connector, the basic intraar ticular pressure was measured directly without injection of any physio logical saline solution into the joint before measurement. The initial intraarticular pressures were all negative with a mean value of -67.8 mm Hg. During abduction-adduction movement the minimal intraarticular pressure was measured at 20 degrees of humeral abduction. During rota tion the minimal intraarticular pressure was observed at neutral humer al rotation. The intraarticular pressure decreased nearly linearly wit h increasing inferior load on the humerus. These results indicate that the intraarticular pressure takes part in stabilization of the glenoh umeral joint, and the negative intraarticular pressure of the glenohum eral joint induces the maximal stabilizing effect at 20 degrees of hum eral abduction and neutral humeral rotation.