B Rai, R Jain, S Anand, S Dhattarwal
bizygomatic width, nasion to prosthion a point distance, regression equation
B Rai, R Jain, S Anand, S Dhattarwal. Determination Of Foetal Age: Bizygomatic Width And Nasion To Prosthion Distance. The Internet Journal of Forensic Science. 2006 Volume 2 Number 1.
Determination of foetal age is of significant not only in obstetrics management but also in medicolegal cases. Many a medicolegal questions especially related to fetal age are to answered by a forensic pathologist after examining a dead foetus. A study was conducted on 103 foetuses of Haryana population ranging between 8 weeks to 30 weeks in the Department of Forensic Medicine, Pt. B.D. Sharma PGIMS, Rohtak (Haryana). Facial dimensions viz. bizygomati width and nasion to prosthion distance were measured by verniler caliper (having resolution 0.02, instrument private Ltd. New Delhi.). Both the dimensions correlated well with foetal age with correlation coefficient (6) of 0.83 to 0.85 respectively. The equations of regression curves were calculated for two dimensions which can be used as method for age determination of unknown foetus North India population.
The age determination of foetus is important as there will been enhanced punishment, in case, a criminal abortion has been performed after 28 weeks of pregnancey1. The age of foetus may be determined from its length, weight, condition and growth of eyes, eyelashes and eye brows, growth of finger nails, location of testis, appearance of ossification centers2. Some workers like Cussenot O et al3, Guihard Costa AM4, Maydon KL et al5 and Tuli et al6 etc. studies craniofacial dimensions for age determination of foetus at different places. The present study has been taken up to establish suitable regression equitations for age detmrination from Bizygomatic width and nasion to prosthion distance of foetus of Haryana.
Materials And Methods
Hundred and three fresh dead foetus of Haryana subjects of different gestational age ranging from 8 weeks were collected from the department of forensic medicine, Pt. B.D. Sharma PGIMS (Rohtak). Foetuses with gross anatomical abnormalities were excluded.
The fetuses were presented in formalin solution and soft tissues were discussed and removed from the skull. Then with the help of Martin's spreeding calipers the following measurements were recorded for each cases using standard landmarks :-
Distance between nasion to prosthion then the datas were statistical analysis (SPSS software).
Observations And Results
Number of cases studied, mean values of nasion to prosthion bizygomatic width as different age groups are shown in table-I.
The nasion to prosthion and bizygomatic width increases as the age increased and the correlation coefficient were 0.83 and 0.85 respectively and ‘t' value are 2.907 and 3.109 respectively i.e. significant at 5% level of significance. Two regression equations for the determination of age of foetus from (1) nasion to prosthion width been established and standard errors of estimate calculated as in table-II.
Tuli A et al (1995) studied the correlation between craniofacial dimensions and foetal age on the fetuses of North Indian Population and deducted that the correlation coefficient of superior facial height and bizygomatic width with foetal age as 0.99 and 0.95 respectively6. In present series it was 0.83 and 0.85 respectively at 5% level of significance but in Rajlakshmi et al studied that the correlation coefficient superior facial height and bizgyomatic width with foetal age as 0.85 and 0.87 respectively1.
Gushard Casta AM (1988) traced the craniofacial growth curves from known foetal skulls. He opined that foetal skull may provide foetal age by means of regression curves4. Cussenot et al (1990) established that superior facial height can be used as a predictor of foetal ages. They found a good correlation between superior facial height and foetal age (r=0.96) and observed that the mean growth rate was 1.3mm 1 per week upto 34 week after which it decreased to 0.5mm per wek.3
With substantially improved ultrasound imaging it is now possible to identify previously inaccessible structures, such as fetal face. The standard measurements for dating pregnancies, the biparietal diameter is virtually impossible to detain when the foetal head in facing straight up or down1 the facial region, however, can identified and measured in an occiput posterior position and it is possible, therefore, that orbital diameters, superior facial height and bizygomatic width could be used to date pregnancies, in lieu of BDD (Mayden K L et al 1982).5 From the present study regression equation are derived which can be used for estimation of age of the foetus from its superior facial height and also from bizygomatic width.
The present study shows statistically significant correlation between the two parameter i.e., nasion to prosthion distance, bizygomatic width and fetal age. The regression equation calculated for both the parameters can be used for estimating the foetal age of unknown gestation period. This study will not only help obstetricans in determining gestational age but also to medicolegal experts and thus will help in administration of justice.
Dr. Balwant Rai S/o Sh. Ram Swaroop Village Bhangu Distt. Sirsa P.O. Sahuwala-First Haryana Ph : 0091-9812185855 e-mail: drbalwantraissct@rediffmailcom