Cephalic Index (CI)

Definition: (BPD ÷ OFD) × 100.

Interpretation: CI >85 → Brachycephaly; CI <70 → Dolichocephaly.

Clinical Use: Helps interpret HC and BPD in the context of head shape anomalies.

Gestational Age (Weeks)	Normal CI Range (%)	Interpretation
14–16	72–84	Within normal limits
17–20	71–85	Within normal limits
21–24	70–86	Within normal limits
25–28	70–85	Within normal limits
29–32	70–85	Within normal limits
33–36	70–85	Within normal limits
37–40	70–85	Within normal limits

Note: Minor variations exist across populations and machines. Always interpret CI alongside BPD, OFD, HC, and clinical context.

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Note: If you select English, answer all questions in English.
यदि आप हिंदी चुनते हैं, तो सभी प्रश्न हिंदी में हल करें।

1. What does the Cephalic Index (CI) measure? 1. सेफेलिक इंडेक्स (CI) क्या मापता है?
A. Ratio of OFD to FL
B. Ratio of BPD to HC
C. Ratio of BPD to OFD × 100
D. Ratio of AC to HC

2. Which formula is correct for Cephalic Index (CI)? 2. सेफेलिक इंडेक्स (CI) का सही सूत्र कौन सा है?
A. (HC / AC) × 100
B. (BPD / OFD) × 100
C. (OFD / BPD) × 100
D. (BPD / FL) × 100

3. What is the normal range of Cephalic Index (CI)? 3. सेफेलिक इंडेक्स (CI) की सामान्य सीमा क्या है?
A. 50–60%
B. 70–85%
C. 90–100%
D. 100–120%

4. A CI greater than 85% suggests? 4. 85% से अधिक CI क्या दर्शाता है?
A. Dolichocephaly
B. Brachycephaly
C. Microcephaly
D. Normal head shape

5. A CI less than 70% suggests? 5. 70% से कम CI क्या दर्शाता है?
A. Brachycephaly
B. Dolichocephaly
C. Hydrocephalus
D. Normal

6. CI is mainly calculated using which fetal measurements? 6. CI मुख्य रूप से किस भ्रूण माप का उपयोग करके गणना किया जाता है?
A. BPD & OFD
B. AC & FL
C. HC & FL
D. FL & CRL

7. What type of head shape is indicated by brachycephaly? 7. ब्रेकीसेफली किस प्रकार के सिर के आकार को दर्शाता है?
A. Long and narrow head
B. Short and broad head
C. Small head
D. Normal head

8. Which fetal condition may cause abnormal Cephalic Index? 8. कौन सी भ्रूण स्थिति असामान्य CI का कारण बन सकती है?
A. Oligohydramnios
B. Breech presentation
C. Multiple pregnancy
D. All of the above

9. Why is CI clinically important? 9. CI नैदानिक रूप से क्यों महत्वपूर्ण है?
A. To assess fetal growth
B. To identify abnormal head shapes
C. To diagnose placenta previa
D. To measure amniotic fluid

10. CI is most useful in which trimester? 10. CI किस त्रैमास में सबसे उपयोगी है?
A. First trimester
B. Second trimester
C. Third trimester
D. At birth

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Cephalic Index (CI) Calculator

BPD (mm): OFD (mm):