Which Landmark Is Used to Measure Abdominal Girth? An Expert's Guide

October 2, 2025 •

3 min read

According to the World Health Organization, waist circumference is a key indicator of metabolic syndrome, even in people with a normal Body Mass Index. Knowing which landmark is used to measure abdominal girth or waist circumference is essential for consistent and reliable health monitoring.

Quick Summary

The specific landmark for measuring abdominal girth depends on the protocol being followed; general measurements often use the umbilicus (navel), while more standardized health assessments, like those for waist circumference, use the top of the iliac crest (hip bone) or the midpoint between the last rib and the iliac crest.

Key Points

Umbilicus: The belly button is often the landmark for general abdominal girth measurements.
Iliac Crest: The top of the hip bone is the standard landmark for waist circumference, a measure used to assess metabolic disease risk.
Standard Protocols: Organizations like the NIH and WHO recommend using the iliac crest or a midpoint for health risk assessments.
Consistency is Key: Using the same measurement method and landmark each time is crucial for tracking changes accurately.
Health Risk Indicator: A large waist circumference is a better predictor of health risks like heart disease than BMI alone, as it accounts for abdominal fat distribution.
Measurement Technique: The tape should be horizontal, snug but not tight, and the measurement should be taken at the end of a normal exhale.

Understanding the Landmarks: Umbilicus vs. Iliac Crest

While the terms "abdominal girth" and "waist circumference" are sometimes used interchangeably, different protocols and anatomical landmarks exist for each measurement. It is critical to use the correct and consistent landmark to ensure accurate data and to be able to compare measurements over time. The two most common methods involve either the umbilicus or the iliac crest.

The Umbilicus: The Landmark for Abdominal Girth

For general clinical assessments, such as monitoring fluid accumulation, the umbilicus (navel) is a frequently used landmark. The measurement is taken at the level of the belly button.

The Iliac Crest: The Standard for Waist Circumference

For assessing the risk of chronic diseases, guidelines from organizations like the NIH and WHO recommend using bony landmarks like the iliac crest (upper hip bone). The NHANES protocol specifies the landmark as just above the uppermost lateral border of the right iliac crest. This method is highly standardized.

Why Consistent Measurement Matters

Consistent landmark usage is vital for accurate health tracking. Small variations in measurement location can significantly alter readings and affect the interpretation of health risks. High waist circumference thresholds (e.g., over 40 inches for men, 35 for women) rely on standardized methods for meaning.

Comparison of Abdominal Measurement Protocols

Different contexts and organizations utilize varying protocols. Below is a comparison of the umbilical and iliac crest methods.


Feature	Abdominal Girth (Umbilical)	Waist Circumference (Iliac Crest/Midpoint)
Primary Landmark	Umbilicus (belly button)	Iliac crest (top of hip bone) or midpoint between last rib and iliac crest
Purpose	Monitoring fluid/gas changes, general abdominal size	Assessing metabolic disease risk associated with abdominal fat
Standardization	Less standardized, can vary by practice	Highly standardized (e.g., WHO, NHANES protocols)
Clinical Application	Quick monitoring of conditions like ascites	Long-term tracking of obesity-related risk factors

Health Implications of Abdominal Fat

Excess abdominal fat, particularly visceral fat, is strongly associated with increased risk for several serious health issues, including:

Type 2 diabetes
Heart disease
High blood pressure
High cholesterol
Metabolic syndrome

Measuring waist circumference consistently provides valuable data for health assessment, offering insights beyond BMI which doesn't account for fat distribution.

How to Interpret Your Results

Interpreting waist circumference requires understanding established high-risk thresholds, such as those provided by the CDC and NIH. Generally:

Men: A waist circumference greater than 40 inches (102 cm) indicates increased health risk.
Women: A waist circumference greater than 35 inches (88 cm) indicates increased health risk.

Keep in mind these are general guidelines, and personalized risk assessment should involve a healthcare professional.

Conclusion: Selecting and Sticking to a Method

To determine which landmark is used to measure abdominal girth?, the answer depends on the measurement's purpose. The umbilicus is common for general monitoring, while the iliac crest is standard for specific health risk assessments.

Consistency in method and landmark is crucial for accurate tracking of changes in abdominal measurement over time, providing valuable health insights. For further details on waist circumference measurement, consult the {Link: CDC's guidance on healthy weight https://www.cdc.gov/diabetes/living-with/healthy-weight.html}.

Frequently Asked Questions

Abdominal girth typically refers to a measurement taken at the level of the umbilicus (navel) for general monitoring. Waist circumference, used for assessing health risks, is a more specific measurement taken at a bony landmark like the iliac crest (hip bone).

Different methods exist for different purposes. Measuring at the umbilicus is useful for quick clinical checks, such as monitoring fluid buildup. Using the iliac crest is a more standardized approach for assessing long-term health risks associated with abdominal fat accumulation.

For assessing the risk of heart disease and other chronic conditions, waist circumference measured using the iliac crest landmark is generally considered more accurate and is the standard for most health organizations like the World Health Organization.

To find your iliac crest, place your hands on your hips with your thumbs pointing backward. The top, bony part of your pelvis that you feel is the iliac crest. For a proper measurement, locate the uppermost lateral border of this bone.

For the most accurate results, you should measure on bare skin. If that's not possible, wear only light, form-fitting clothing that won't add bulk or distort the measurement. Always be consistent with your approach.

For tracking health, a weekly or bi-weekly measurement can be useful. It is important to measure at the same time of day and under similar circumstances to minimize variations caused by bloating or digestion.

High-risk thresholds are generally defined as a waist circumference over 40 inches (102 cm) for men and over 35 inches (88 cm) for women, according to guidelines from health organizations like the NIH.