Blood Pressure Is Normally Consistent Throughout the Body, With Minor Gravitational Fluctuations
Systemic arterial pressure is generated by the left ventricle and transmitted throughout the arterial tree. At the same vertical level, pressure is nearly identical (within measurement error).
Hydrostatic gradient: ~0.77 mmHg per cm vertical height difference (blood density ~1.06 g/mL).
- Arm (heart level) vs. leg (standing): ~80–100 mmHg higher in leg due to gravity.
- Supine: Arm ≈ leg (same horizontal plane).
- Clinical implication: Measure BP at heart level (arm supported). Ankle-brachial index (ABI) compares systolic ankle/arm to assess PAD, not absolute leg pressure.
Pathologic discrepancies (e.g., subclavian stenosis, coarctation, aortic dissection) cause true inter-arm or arm-leg gradients. Routine bilateral BP measurement detects these.
Hypertension - Related Articles
- Blood Pressure 124/54: Interpretation & Clinical Significance
- Understanding Blood Pressure Readings: Systolic & Diastolic Explained
- Understanding High Blood Pressure: Risk Factors & Prevention
- Understanding Optimal Blood Pressure: Systolic & Diastolic Readings
- Blood Pressure 144/107 mmHg: Stage 2 Hypertension – What You Need to Know
- High Blood Pressure and Organ Damage: What You Need to Know
- Blood Pressure Regulation: Baroreflex (Negative Feedback) & Labor (Positive Feedback)