Age Estimation from the Rib by Components Method Analysis in Indian females

The sternal ends of the ribs are a reliable method of age estimation from late adolescence to old age. Iscan et al developed a phase analysis method based on the morphologic changes at the sternal extremity of the fourth rib, is one of the best effective for age estimation at death. The present study is designed to evaluate the applicability of Component method developed by Iscan et al, to Indian females. The sample consisted of fourth ribs on right side from 63 females of known age and race. Statistical analysis indicated that these changes were age related and applicable to Indian females also. Introduction This research evaluates the accuracy of the component method developed by Iscan et al (1984a) on a large sample of sternal rib ends that was collected for this research. Age estimation by metamorphosis of sternal end of fourth rib is considered one of the most reliable site at present for the assessment of age at death in the adult skeleton (M.Y. Iscan, S.R. Loth. 1997). Iscan’s rib phase method has shown sternal end of IV rib as a reliable indicator of age at death in the adult skeleton (Iscan et.al, 1984, Iscan et.al. 1985). There are several studies for age determination from the skeleton such as cranial suture closure (Mann et al, 1991, Mann et al, 1987), pubic symphysial metamorphosis (Snow C.C, 1983, Klepinger et al. 1992, Murray et.al 1991), morphologic changes of the sternal end of the rib; microscopic analysis of bone (osteon counting) (Nelson, R.1992, Stout, S. D 1986, Dudar JC et.al 1993). Pubic symphysis and cranial sutures have a high degree of individual variation (Snow C.C, 1983, Klepinger et.al 1992.). The morphologic changes of the rib by normal aging process are sex specific (M.Y. Iscan et al., 1984, M.Y. Iscan et al., 1985, Iscan MY 1987, Iscan MY & Loth SR.1986, Loth SR et.al 1994). Iscan’s rib phase method had gained widespread acceptance for both age and sex (Iscan et.al, 1984, Iscan MY 1987, Iscan MY & Loth S. R.1986, Loth SR et.al 1994), and the need of modifications for different races has been explored (Iscan M.Y. 1987, Loth S.R. et al. 1994) In 1984 Iscan et al. developed component method by using sternal end of fourth rib on white males (Iscan MY et.al, 1984a). Iscan et al. (1984) also developed phase analysis method on white males and in white females (Iscan et.al, 1984, Iscan et al. 1985). Oettle and Steyn(2000) and Yavuz (1998) also applied phase analysis method on South African blacks and Turks respectively. A large scale study using sternal end of fourth rib by phase analysis method in Indian population has proved that the phase method and component method (in males) developed by Iscan et al is useful for Indian population also (Padmakumar K .et al 2009, Mahesh Chand Meena et.al 2012, Mahesh Chand Meena et.al 2013, Mahesh Chand Meena et al 2014). 1 Senior resident Department of Forensic Medicine and Toxicology Lady Hardinge Medical College and Associated Hospitals, New Delhi India. (Corresponding author) Email: [email protected] 2 Professor & Head, Department of Forensic Medicine and Toxicology Lady Hardinge Medical College and Associated Hospitals, New Delhi India. 3 Director Professor, Department of Forensic Medicine and Toxicology Lady Hardinge Medical College and Associated Hospitals, New Delhi India Antrocom Online Journal of Anthropology 2014, vol. 10. n. 2 – ISSN 1973 – 2880 143 Meena M. C., Rani Y. & Sharma G. K.– Age Estimation from the Rib In the present study, the sternal end of rib is used for determination of age by direct observation of medial end of IV rib is examined with special attention to depth and shape of the pit along with the walls and rim surrounding it. Our present study evaluates the applicability of Component method developed by Iscan et al in 1984a, when applied to Indian females. Material and method This study includes 63 females cases with known age, and sex, specimens were collected at the Department of Forensic Medicine and Toxicology, Lady Hardinge Medical College & associated Hospitals, New Delhi between Nov 2009 and Mar 2011. These cases were chosen from different age groups. Sternal ends of the 4th rib were removed few cm from the costochondral junction and placed in glass containers were filled with water and the ribs were left to soak for several weeks. The ribs were finally cleaned, removing any remaining soft tissue, after which they were dried and marked by using an indelible pen and attaching labels. The morphologic changes in the form, shape, texture and overall quality of specimens were evaluated without any knowledge about the patients Our initial observations revealed that the first morphologic changes, beyond an increase in size, were not seen in the sternal extremity of the rib until after the age of 14 years. This may signify the cessation of growth, and thus would indicate that maturity in the rib is reached by the end of the 14 year. Therefore, the only specimens 14 years and older were included in the statistical analysis (Table 1). In 1984, İscan and colleagues used component analysis to associate observed changes in pit depth (component 1), pit shape (component 2), and, rim and wall configuration (component 3) each of which was divided into six stages as follow: Component I: Pit depth that is the maximum depth of the pit is measured with the depth calliper calibrated to 0.1mm). It is divided into following six stages: 0 Flat to slight billowy extremity with no indentation (pit) greater than 1,1 mm. 1. Definite pit formation with a depth ranging from 1.1 to 2.5mm. 2. Pit depth ranging from 2.6 to 4.5mm. 3. Pit depth ranging from 4.6 to 7mm. 4. Pit depth ranging from 7.1 to 10mm. 5. Pit depth of 10.1mm or more, Component II: Pit shape. It is divided into the following 6 stage 1. No pit formation at the flat and billowy articular surface. 2. A shallow amorphous indentation. 3. Formation of V shape pit with thick walls. 4. The pit assumes a narrow U shape with fairly thick walls. 5. Wide U shape pit with thin walls. 6. Pit is still wide U shaped, yet deeper, more brittle and poorer in texture with some disintegration of bone. Component III: Rim and wall configuration. It is divided into following six stages: 0. Smooth regular rim with no wall formation. 1. Beginning walls with a thick, smooth regular rim. 2. Definite visible walls that is thick and smooth with a scalloped or slightly wavy rim. 3. The scalloped edges are disappearing wall are thinning yet the wall are fairly without fairly study without significant deterioration in the texture. 4. The rim is becoming sharper and increasingly irregular with more Frequent bony Projection, often more pronounced at the cranial and caudal margins. The walls Shows further thinning cranial and are less sturdy with noticeable deterioration in texture. 5. Texture shows extreme friability and porosity, rim is very sharp, brittle and highly irregular with long bony projection. Occasionally windows are formed in areas where the walls are incomplete. Antrocom Online Journal of Anthropology 2014, vol. 10. n. 2 – ISSN 1973 – 2880 144 Meena M. C., Rani Y. & Sharma G. K.– Age Estimation from the Rib Observations and result Table 2 shows the descriptive statistics and 95%confidence interval of the mean for the components, individually and in total. Based on the five stages considered in the analysis of component I (pit depth), the age increased 8 year or more from stage 1 through 5. component II (pit shape), the mean age rose about 15 year in stages 1 through 5, except in between 1 and 2 but in component components III mean age gradually increase with increase age interval in between stages this suggested that changes occur more rapidly prior to age 30 The range of the 95% confidence interval showed a gradual increased in stage 1 through 5. Following the individual analysis of each component, they were summed (component I + II + III) to obtain a total score per rib (Table 2). These scored ranged from 3 to 15 and the mean age per score increased from 20 to 75. Inconsistencies occurred only with scores of 11, 12 and 13 and did not exceed 1 year. The result of the analysis of variance and related statistics appear in table 3. Component I and III attained the highest fratio indicating that they are more age dependent than component II. The F ratio showed that the variation between the stages was statistically significant in all components of the probable level less than 0.001. Whereas eta square (η2) values which explained the percentage of variation in the age variable that can be attributed to the metamorphoses chosen to define the components. Component I, individually attained the greatest percentage (η2 =80%). This was narrowly followed by component III (64%), with component I a distant third. Combining all three increased this figure only slightly to 83% Discussion Osteological changes to the sternal rib ends have also shown to be useful in adult age estimation, currently most anthropologists employ the technique describe by Iscan et.al 1984a 1984b. The rates of these changes are parallel to age and these changes are also different in females and males requiring the development of different standards (Aktas EO et.al2004). Several previous studies have reported variation in rate and morphological pattern of age associated changes in the sternal end of the ribs between various groups, and thus in present study we discuss about the applicability of this component method which must be evaluated particularly if this technique is needed to be employed in medico-legal proceeding. Iscan findings indicate that the cortex became thinner with age but the actual diameter of the bone increased. Similarly this information agreed with our own observation of pronounced changes in bone density and texture seen in the later stages of each component. The sternal extremity of each rib was analysed in relation to pit depth (component I), pit shape (component II) and wall configuration (component III). Mean age in all components gradually increasing for score 1 through 5 in present study. Results indicated that the age at death can be estimated from the rib within about 3 years in between third & fourth decade to about 6 years in the sixth decade an seventh decade of life. Pit depth and rim wall configuration yielded better result than absolute pit shape alone. However total component score is better than individual component alone. The analysis of variance statistic was found in total component score to be 73% in Iscan et.al study (1984a) and 79% in Meena et.al study(2014) while in the present study was found 83%. As a result, 83% of the changes occurring with age can be accounted for by the characteristics chosen to delineate the component (I+ II+ III). In general, the results of this study shows that component method is also applicable for estimation of age in Indian females and they revealed that rate and morphological pattern in the sternal end of the ribs are associated with age. Conclusion In conclusion, it is essential, especially in medico-legal cases, to have demographic methods known to be accurate on adult Indian since few standards have actually be developed from Indian specimens(Meena et.al 2012, Meena et.al 2013, Meena et.al 2014). The results of this study reveal that morphological changes in the sternal ends of the fourth ribs gave an encouraging result for estimation of age in females by component method also. Component method can accurately estimate age in Indian throughout the adult life span. Antrocom Online Journal of Anthropology 2014, vol. 10. n. 2 – ISSN 1973 – 2880 145 Meena M. C., Rani Y. & Sharma G. K.– Age Estimation from the Rib