Which cuff width relative to the arm circumference is recommended for accurate blood pressure measurement?

• A. 20% of arm circumference
• B. 40% of arm circumference
• C. 60% of arm circumference
• D. 80% of arm circumference

Answer: (B)

Proper cuff sizing is essential for accurate BP measurement. The cuff width should be about 40% (two-fifths) of the arm circumference. This width provides enough compression of the brachial artery to occlude it reliably without applying excessive pressure. If the cuff is too narrow, it tends to produce artificially high readings because more pressure is focused over a smaller area. If the cuff is too wide, it may not occlude the artery effectively, which can lead to inaccurate (often lower) readings. Using a width around 40% helps ensure the measurement reflects true arterial pressure across different arm sizes. For best accuracy, also ensure the cuff length covers roughly 80% of the arm circumference so the bladder sits properly over the artery.