Abstract
Cephalic Index has been one of the most studied topics in Physical Anthropology. With the advancement of DNA technology, Racial theories are changing drastically. Still, the concept of the cephalic index is relevant in the present context for various reasons like correction of sagittal synostosis, making of head-worn objects like earphones, helmets, etc., Identification, and Cosmetic and Facial reconstruction purposes. Very few studies have been done to measure the cephalic index after reflection of the scalp on cadavers. The present study was done on cases coming for autopsy at the tertiary hospital in the capital of India. A more accurate result for the measurement of the cephalic index has been obtained, which will be helpful for identification purposes in skeletonized bodies. This was a cross-sectional, prospective, and observational study. Two hundred two post-mortem cases (46 females and 156 males) satisfying our inclusion and exclusion criteria in the age group of 7–85 years were examined for skull length and skull breadth as per the standard criteria after reflection of the scalp using a digital vernier caliper, and the cranial index was calculated. The mean biparietal length for the males, females and overall were 133.43, 130.60, and 132.79 (in mm), respectively. The mean occipito-frontal size for the males, females and overall were 172.14, 164.56, and 170.41 (in mm), respectively. The mean cranial index for the males, females and overall were 77.61, 79.46, and 78.04, respectively, that is, all in the category of the Mesati-cephalic. The most typical skull type in both sexes was Mesati-cephalic (male 48.1% and female 41.3%). The second most common was Dolichocephalic (20.5%) among males and Brachycephalic (26.1%) in females, respectively.
Highlights
A more accurate result for the measurement of the cephalic index has been obtained, which will be helpful for identification purposes in skeletonized bodies, as the study was done after reflection of the scalp on cadavers.
The mean cranial index of the Delhi population for the males, females and overall was 77.61, 79.46, and 78.04, respectively, that is, all in the category of the Mesati-cephalic.
We observed that 80.69% of the study population, with 81.41% males and 80.43% females, belong in the cephalic index range of 72.5–84.9.
We propose that a cephalic index value of 72.5–84.9 or any more precise value after further studies can be used to identify people of the Indian geographical region, as they have distinct morphological traits.
Introduction
The history of the cephalic index goes back to the Swedish professor of anatomy, Andres Retzius (1796–1860), who first applied it in Physical Anthropology to classify human remains found in Europe. 1 Further human individual’s head shapes were classified correctly (Hyper-dolichocephalic, Dolicho-cephalic, Mesati-cephalic, Brachy-cephalic and Hyper-Brachy-cephalic) by the Stewart and range for each category was decided (1936). 2
Since then, cephalic index has been one of the most studied topics in Physical Anthropology. With the advancement of DNA fingerprinting, Racial theories are changing drastically. Still, the concept of a cephalic index is relevant in the present day as well for various reasons other than race identification, like correction of sagittal synostosis, making of head-worn objects like earphones, helmets, etc., Identification, Cosmetic and Facial reconstruction purposes.
For forensic purposes, identifying skeletal remains is challenging; the cephalic index can play a significant role in some instances. Most studies on the cephalic index have been done on living subjects. So, applying the same values for the race determination on the skeletal remains poses a risk of scalp thickness bias. For this, we need to develop data on skull parameters after reflection of scalp tissues.
With these lacunae, the present study was done on cases coming for autopsy at the tertiary hospital in the capital of India, and the cephalic index was calculated after the reflection of the scalp tissues. A more accurate result for the measurement of the cephalic index has been obtained, which will be helpful for identification purposes in skeletonized bodies. Also, the study was done on the population of Delhi with the objective of finding a cephalic index value in the Delhi region. The advantage of calculating the cephalic index value from the capital of India is that Delhi is a cosmopolitan city where people from different parts of India reside. So, the result of the cephalic index value of Delhi may reflect the cephalic index of India.
Material and Methods
The study was conducted in the Department of Forensic Medicine & Mortuary of Atal Bihari Vajpayee Institute of Medical College & Ram Manohar Lohia Hospital, New Delhi. The study was conducted over six months. We obtained written and informed consent from the deceased’s parents/guardians/relatives. This was a cross-sectional, prospective, and observational study. Study populations were dead bodies coming for the Medico-legal post-mortem examination at the mortuary. A convenient sample size of about 200 cases was taken. The inclusion criteria were all dead bodies coming into the morgue for post-mortem examination during this period, while the exclusion criteria were: (a) Bodies with skull deformity, (b) bodies with fracture of the skull, (c) known cases of bone pathology, (d) severely burned bodies, (e) declared bodies of foreign origin. Ethical Clearance for the study was obtained from the Institutional Ethical Committee of Atal Bihari Vajpayee Institute of Medical College & Ram Manohar Lohia Hospital, New Delhi vide File No. 488(24/2021)/IEC/ABVIMS/RMLH/ 558 dated 02.06.2021.
Methods
Bodies coming for post-mortem examination were included in the study as per our exclusion and inclusion criteria. Bodies satisfying our criteria were examined for various skull measurements after reflection of the scalp using a vernier caliper. A digital Vernier caliper of Insize brand (Code no.1108-300) with a range of 0–300 mm/0–12 and measurement accuracy of +0.003 mm was used for all the skull measurements. In the present study, all measurements were carried out by a single, well-trained member of our team to minimize variability. Standard anthropometric techniques were employed using a calibrated digital vernier caliper, with measurements recorded to two decimal places. Although intra- and inter-observer reliability testing was not performed separately, given the standardized methodology and single-observer design, the scope for variation is minimal. The following measurement criteria were followed:
Head Length: It was measured as a straight distance between the glabella (a point above the nasal root between the eyebrows and intersected by the midsagittal plane) and the opisthocranion (The distal-most end placed on the external occipital protuberance in the midsagittal plane)
Head Breadth: It was measured as the maximum transverse diameter between two euryons (the lateral-most point placed on the sides of the head). Cephalic Index was calculated as:
Cephalic index = Maximum breadth of skull/ Maximum length of skull * 100
Depending upon this index, the types of head shapes are grouped into the following categories (Table 1). Microsoft Excel was used for data registration, and IBM SPSS 31.0.0 (Statistical Package for Social Science) for statistical analysis. We applied descriptive statistics and calculated data in the form of mean, median and percentage. Standard deviation and confidence interval for the overall cephalic index value were calculated using an online statistical tool (calculator.net). ANOVA for comparison of the difference in the Male and Female cephalic index values from Table 9 was performed using social science statistics available online.
Showing Different Kinds of Skulls and Their Cephalic Index Value.
Results
A total of 202 Post-mortem cases (46 females and 156 males) in the age group of 7–85 years were examined. The mean occipito-frontal length for the males, females and overall were 172.14, 164.56, and 170.41 (in mm), respectively (Table 2). Among males, 90.1% of the Occipito-frontal length (Head length) was 160.1–180 mm. Among females, 82.6% of the Occipito-frontal length (Head length) was 150.1–170 mm (Table 3). The mean biparietal length for the males, females and overall were 133.43, 130.60, and 132.79 (in mm), respectively (Table 4). Biparietal length (Head breadth) was 120.1–140 mm for 85.3% and 89.1% of the male and female study population, respectively (Table 5). The mean cranial index for the males, females and overall were 77.61, 79.46, and 78.04, respectively, that is, all in the category of the Mesati-cephalic (Table 6). The median value of the cranial index for the males, females and overall was 77.31, 78.52, and 77.65, respectively, that is, all in the category of the Mesati-cephalic (Table 6). The population distribution of the cephalic index was maximum in the cranial index range of 72.5–84.9 with about 81.41%, 80.43%, and 80.69% for males, females and overall, respectively (Table 7). The most typical skull type in both sexes was Mesati-cephalic (male 48.1% and female 41.3%) (Table 8, Figures 1–3). The second most common type of skull was Dolichocephalic (20.5%) among males and Brachycephalic (26.1%) among females (Table 8, Figures 1–3). The standard deviation for the overall cephalic index value was found to be 4.706 with a confidence interval of 0.331. On performing ANOVA on Table 9, for comparison of the Male and Female cephalic values, there is no significant sexual variation noted with the F-ratio value: 3.48, and the p value is .069 (>.05).
The Distribution of Skull Shapes Among Males.
The Distribution of Skull Shapes Among Females.
The Overall Distribution of Skull Shapes in the Study Population.
Showing Measurement of Head Length (Occipito-frontal Length) (in mm).
Showing the Distribution of Head Length in the Study Population.
Showing Measurement of Head Breadth (Biparietal Length) (in mm).
Showing the Distribution of Head Breadth in the Study Population.
Showing Cranial Index Value of the Study Population.
Showing the Distribution of the Cephalic Index in the Study Population.
Showing the Distribution of Skull Shapes in the Study Population in Percentage.
Comparative Analysis of Cephalic Index Values in Various Study Populations in India.
Discussion
Delhi, the capital of India, is considered to be representative of the people of India. The present study on measuring the cephalic index was done on the population of Delhi in a tertiary care hospital on the dead bodies after reflection of the scalp tissues. Identifying the skeletal remains is one of the significant challenges for an autopsy surgeon. As most studies on the cephalic index have been done on living subjects, using the same data on the skeletal remains increases the chances of systematic bias. For this, identification of the race and facial reconstruction can be better possible if data are available in skeletonized conditions. Sharma RN found that due to the difference in the soft tissue thickness, the cranial index is two units higher among living subjects than that measured on the dried human skull. 3 Many studies have reported that readings of the measurement with soft tissue give higher values than those without soft tissue.
Interestingly, soft tissue thickness differs not only individually but also locally from one site to another. Chakrabarti et al. 4 noted that calculations should be done without soft tissue to find a precise cephalic index. Given the above, the present study adds to the available data on the cephalic index of the Indian population, particularly for the skeletal remains.
In the present study, the cephalic index ranges from 61.93 to 92.01, with a mean value of 78.04. Among all the participants in the survey, Mesati-cephalic was the dominant head shape, followed by Brachycephalic and then Dolichocephalic type. The mean cephalic index for females (79.46) was higher than for males (77.61) in our study. The second most common among males was found to be the Dolichocephalic type, followed by Brachycephalic and vice versa in the case of females. The general tendency of the study population was toward Mesati-cephalic and Brachycephalic cranial index values. Data from the present study were compared with earlier studies conducted in the various parts of India on the cephalic index, as tabulated in Table 9.5–22
Findings of our study on Delhi population are similar (Mesati-cephalic) to studies done by Khair et al. (2011) 9 on Mumbai population, Salve et al. (2011) 10 on Andhra population, Yagain et al. (2012) 11 on Karnataka population, Gujaria and Salve (2012) 13 study on Maratha and Andhra population, Patro et al. (2014) 17 on Odisha peoples, Shah et al. (2015) 7 studies on Gujrat population, Setiya et al. (2018) 22 on Madhya Pradesh population and Khanduri et al. (2021) 23 studies done on the peoples of Uttar Pradesh of India.
The shape of the skull is affected by multiple factors, including genetic and environmental factors. 24 Tropical regions are found to have longer heads (Dolichocephalic), while temperate climatic zones present more of a round head shape (Mesocephalic or Brachycephalic). 25 India has a remarkable climate pattern, with tropical in the South and temperate in the northern region. So, the skull shape also shows variations in different areas. Most studies point to the tendency of Indian skull cephalic index values toward brachy-cephalization, which the present research supports.
Brachy-cephalization of the skull and changes in the shape of the head in the population over a long period a known phenomena reported in various literature.26–28 The literature points out that such changes over the period are mainly due to the changes in the standard of living, a drop in infant mortality and movements of the people. This needs to be assessed in the Indian population by further studies with large sample sizes and comparing data from previous studies chronologically for the best results.
Does India Need an Indian Cephalic Index?
Coon (1965) 29 divided the human species into four races: Caucasoid, Mongoloid, Australoid, and Negroid, based on morphological traits like skin color, differences in eyes, nose, skull shape, blood group, etc. Indians have not been included in the above four races and are considered mixed. However, India is one of the world’s oldest civilizations, with people residing there for a long time. Still, Indians are not recognized as a separate race. In the present study, we observed that 80.69% of the study population, with 81.41% males and 80.43% females, belong in the cephalic index range of 72.5–84.9. Also, Indians have distinct morphological traits from Caucasians, Mongoloid, Africans and Australians. The classification of the head shapes with cephalic index values is not a precise natural classification, but an observed, convenient classification by different scientists. So, we propose that for the convenience of identity and other purposes, a cephalic index value of 72.5–84.9 or any more precise value can be used to identify people of the Indian geographical region. We suggest conducting more studies comprising a more extensive study population and broader geographical coverage to establish a more accurate value.
Limitations of the Study
The study is limited by the lack of data on genetic and regional variations, factors that could influence the results and restrict their wider applicability. In addition, the relatively small sample size reduces the strength of the conclusions, making this work preliminary in nature. Broader generalization would require validation through larger, multi-regional studies with more diverse populations.
Conclusion
The present study shows that a significant population of Delhi belong to the Mesati-cephalic category of head shapes. The mean cranial index of females is greater than that of males. The tendency of the population is more toward Brachycephalic than Dolichocephalic. More than 80% of the Delhi population falls under the cephalic index range of 72.5–84.9. The results of this study can be used by anthropologists and forensic experts for various anthropological studies in future and may help forensic experts identify unknown bodies.
Footnotes
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethical Approval
Ethical approval for the study was obtained from the Institutional Ethics Committee of Atal Bihari Vajpayee Institute of Medical College and Ram Manohar Lohia Hospital, New Delhi (File No. 488(24/2021)/IEC/ABVIMS/RMLH/558), dated June 2, 2021.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Informed Consent
Informed written consent was obtained from the next of kin of the deceased.
