Which Artery to Use for Manual Blood Pressure Measurement
The brachial artery is the standard and only recommended artery for manual blood pressure measurement, with the stethoscope placed at the elbow crease over the brachial artery and the cuff positioned on the upper arm. 1
Standard Measurement Location
The upper arm with auscultation over the brachial artery is the gold standard location for blood pressure measurement, as established by the American Heart Association guidelines 1
The cuff should be wrapped around the upper arm with its midpoint positioned directly over the brachial artery 1, 2
The stethoscope bell or diaphragm must be placed at the antecubital fossa (elbow crease) directly over the brachial artery to detect Korotkoff sounds 1
Why the Brachial Artery is Essential
Brachial artery pressure is the measurement used in all major epidemiological studies that established the relationship between blood pressure and cardiovascular outcomes, making it the only clinically validated site 1, 2
Blood pressure varies substantially throughout the arterial tree—systolic pressure increases and diastolic pressure decreases in more distal arteries like the radial artery 1
Research demonstrates that radial systolic BP averages 5.5 mm Hg higher than brachial systolic BP, with only 43% of patients having radial readings within ±5 mm Hg of brachial measurements 3
Alternative Sites Are Not Recommended for Routine Clinical Use
The radial artery (wrist) is not suitable for standard manual BP measurement because systolic and diastolic pressures differ significantly from brachial values 1, 3
Wrist monitors require the wrist to be held precisely at heart level, increasing the risk of measurement errors 1, 2
The American Heart Association explicitly states that wrist monitors are not recommended for routine clinical use 1
Finger monitors have been found to be very inaccurate and should never be used 1, 2
Critical Technical Points
The arm should be supported at heart level on a flat surface during measurement 1, 2
The patient should be seated with back supported and both feet flat on the floor after 5 minutes of rest 1, 2
Proper cuff size is essential—the bladder width should be 40% of mid-arm circumference 4
The midline of the cuff bladder must be positioned over the brachial artery, though research shows oscillometric devices maintain accuracy even with some positional variation 5
Common Pitfalls to Avoid
Never use the radial artery for manual auscultatory blood pressure measurement—it is only appropriate for specialized tonometry research techniques that are not validated for clinical practice 1
Avoid measuring BP with the arm hanging below heart level, as hydrostatic pressure adds 13-14 mm Hg to readings 6
Do not use excessive cuff inflation pressures (>300 mm Hg), as this can induce transient blood pressure elevation 7
In patients with very faint Korotkoff sounds (such as those with muscular atrophy), a Doppler probe can be placed over the brachial artery to detect systolic pressure 1