No, the stethoscope should NOT be placed under the blood pressure cuff during standard auscultatory measurement.
The American Heart Association guidelines explicitly recommend placing the lower end of the cuff 2 to 3 cm above the antecubital fossa to allow room for placement of the stethoscope OUTSIDE the cuff, with the stethoscope positioned over the brachial artery in the antecubital fossa 1.
Key Reasoning
The standard technique requires the stethoscope to be placed:
- Outside and below the cuff edge (not underneath it)
- Directly over the palpated brachial artery in the antecubital fossa
- With 2-3 cm clearance between the cuff's lower edge and the stethoscope placement site
Critical Caveat About Cuff Contact
If the cuff touches the stethoscope during measurement, artifactual noise will be generated, which compromises measurement accuracy 1. This is why proper spacing is essential. If a cuff that maintains this spacing doesn't adequately encircle the arm (at least 80% bladder length), you must use a larger cuff size rather than compromise stethoscope placement.
The Research Evidence Shows Conflicting Results
While guidelines clearly recommend stethoscope placement outside the cuff, research studies have examined placing it underneath:
- Diastolic BP reads approximately 2-3 mmHg LOWER when the stethoscope is under the cuff compared to outside placement 2, 3
- One study suggested this lower reading might actually be closer to true intra-arterial pressure, since traditional outside-cuff placement tends to overestimate diastolic BP 3
- A 1991 study using a hands-free stethoscope fixed under the cuff edge found improved Korotkoff sound clarity and reduced measurement variation 4
Practical Clinical Recommendation
For standard clinical practice, follow the AHA guideline technique with stethoscope placement outside the cuff 1. This remains the validated, standardized approach that:
- Avoids artifactual noise from cuff-stethoscope contact
- Provides reproducible measurements comparable across different observers and settings
- Represents the technique against which automated devices are validated
The research suggesting potential advantages of under-cuff placement is interesting but has not been incorporated into clinical practice guidelines and would require recalibration of BP treatment thresholds if adopted universally.