Auscultatory percussion applied across fractures of the shaft of the femur, humerus, and clavicle may be so interpreted as to indicate the presence of a complete fracture, the relative position of the fragments, and, during the postoperative course, the development of bony union. The stethoscope bell and the percussing finger should be applied over bony prominences on either side of the fracture and the sound so elicited compared with that produced by the same procedure on the normal side. Sound alteration constitutes the criterion of the test. Pitch and quality changes result from free vibration of the separate fragments and, accordingly, signify complete fracture or incomplete union. Appreciable diminution in sound intensity indicates poor conduction and reflects absence of end-to-end contact. The chief merits of the examination method may be summarized as follows:

1. The application of the test is simple, rapid, and entails no discomfort to the patient.

2. The desired information is immediately obtainable.

3. For diagnostic purposes, the test is always available when x-ray facilities are not at hand.

4. In the hospital, it may be employed equally well with the patient on the orthopaedic table, in traction apparatus, in bed, or in a plaster cast, and is consequently applicable during, as well as following, the reduction.

5. For certain purposes, the method appears more accurate than x-ray or fluoroscopy. A. The presence of end-to-end contact may be established with certainty by auscultatory percussion whereas, with x-ray, the true displacement often appears magnified or reduced. (Distortion due to oblique exposure.) B. Determination of the degree of bony union attained is sometimes difficult with x-ray, particularly when plaster or over- abundant callus obscures the fracture area. Auscultatory percussion is in no way affected by these factors.

A diversity of other orthopaedic measures entails the sometimes difficult task of determining the presence of bony contact or bony joint fusion. In general, when the test is applied in such cases, its interpretation will follow the above outlined basic principles. The practical utility of the method in this field is being studied at the present time.