The size of the auscultation head: the larger the contact surface between the auscultation head and the body, the better the sound effect will be picked up. However, the surface of the human body has a curvature. If the chest piece is too large, the ear can not be in full contact with the human body. The sound will not only not be picked up well, but also leak out from the gap. Therefore, the size of the auscultation head should be based on clinical needs. At present, the diameter of stethoscope chestpieces is almost uniform in the range of 45-50 mm. For special cases such as pediatric chestpieces, the diameter is generally 30 mm, and for newborns it is 18 mm.
The material of the stethoscope: The material plays an important role in the sound effect. The sound is transmitted through the air or material, and finally converted into heat and disappears. The transmission of sound waves has almost no attenuation in heavy metals, and is prone to attenuation in lighter metals or plastics. Therefore, high-grade stethoscopes must use heavy metals such as stainless steel or titanium.
The conductive part of the stethoscope: the sound transmission line is also very important. The larger the inner diameter of the pipeline, the shorter the length, and the thicker the tube wall, the better the effect of the stethoscope. The international standard length is 27 inches. The sound transmission pipeline of modern stethoscopes is generally made of PVC, which has good sound effect and beautiful appearance, but has poor stretch resistance and is often bent and easily broken after stretching. After using the stethoscope, she should be hung flat on both sides of the neck. This can be seen in foreign TV dramas and is the standard way to wear a high-quality stethoscope.
