Rev Mex Med Forense, 2019, 4(2):12-23 ISSN: 2448-8011

Morphological study of in of corpses of the Institute of Legal Medicine and Forensic Sciences (Ditanfor), Lima - Peru 2018

Original Article

Murrieta-Angulo, Shirley 1, Tejada-Valdivia, César Andrés 1, Arriola-Guillén, Luis Ernesto 1

Received: November 15, 2018, Accepted: January 15, 2019, Published: May 15, 2019

1 Scientific University of the South, Division of Thanatology, Institute of Legal Medicine and Forensic Sciences, Academic Department of Professional Career in Stomatology, Lima, Peru. Corresponding author: Shirley Murrieta Angulo, [email protected]

SUMMARY in the neurological field, as well as in the forensic field and legal medicine due to its Introduction: Pterion is a craniometric morphological differences existing in point of sutural confluence, observable certain groups of individuals. The present from a lateral view of the ; it study seeks to establish similarity criteria represents a point of reference and access Murrieta S, Tejada CA, Arriola LE. Rev Mex Med Forense, 2018, 4(2):12-23 between the most prevalent morphology during the necropsy of Law to each one of within the Lima, Peru population. them. Methods: 90 adult skulls were examined Results: The types of pterion were bilaterally including both pterion points; identified according to the classification of photographs of both areas were taken, Murphy, 1956; finding the types: looking for determinaning the most sphenoparietal (70%), frontotemporal prevalent morphology within the study (24%), starry (6%) and epipheric in none sample;, the average distances between of the cases. It was recorded that the the ossification center of the pterion and average distance is 40 mm for all cases. the posterior edge of the Conclusions. The results obtained in the were obtained. The sample was constituted sutural morphology of the pterion and the by the skulls of the corpses arrived at the results of the measurements are of Institute of Forensic Medicine and importance for the neurosurgical Forensic Sciences DITANFOR of Lima, approach of the skull, registration in legal Peru in the period of September - medicine, forensic odontologic as well as November of 2018, using an inclusion anthropological studies. criterion of being only skulls of male Key words: Pterion, morphometry, , cadavers of ages between 25 at 75 years, corpses, forensic identification. the photographic images were obtained

INTRODUCTION zygomatic ; while in the catarrhines it is composed of the frontal, sphenoid, Pterion is a craniometric point that parietal and temporal bones [4]. These is located bilaterally; represents the sutural were the fundamental differences between confluence of four cranial bones: frontal, the morphologies of pterions of the first parietal, sphenoid and temporal; it is primates of the New World (platirrinos) visible from a side view of the skull [1]. In and the Old World (catarrhinos); this general, pterion is located two fingers allows to compare it with the morphology above the zygomatic arch, with a width of of current human beings, in order to have the thumb at its back to the frontal an evolutionary record of the morphology of the zygomatic [2]. The of the pterion in current human beings; this morphology of pterion was studied for the would facilitate identification in an first time by Broca in 1875; it was investigation within the forensic field, as classified into three types: sphenoparietal, well as in the clinical setting during an frontotemporal and stellate. Sequentially, intervention of surgical approach in Murphy in 1956 classified them into four neurology. types: sphenoparietal, frontotemporal, stellate and epipheric [3]. This is the case of Natekar's study, which attributes the importance for These studies on morphology were surgeons and radiologists of this essential of great importance in terms of the information, before and during a surgical coincidental relationship in families of intervention [5]; it highlights the location primate individuals of the new world; in of its anatomical site, since it is very close the platyrrinos the pterion is composed of to the and on the the frontal, sphenoid, parietal and left side, to the motor area of Broca's Murrieta S, Tejada CA, Arriola LE. Rev Mex Med Forense, 2018, 4(2):12-23 speech, a decisive implication when 76.5% [11]. It must be taken into account proceeding to perform surgical approaches that the type of pterion is not always the of the anterior and middle cranial fossae same on the right and left sides, but there [6]. The investigation of the morphology was a 77% coincidence in this type of of the pterion was followed from the pterion [12]. In all the studies, it was observations of Broca and Murphy, who established that the skulls are of normal divided them into two trajectories with characteristics, without obvious evidence respect to the nature of the pterion. The of dystrophy, deformities and trauma, due initial studies were exploratory and to rupture or fusion of adjacent bones descriptive, in which patterns of (synostosis) [13]. Sex was also taken into articulation in pterion in humans and account in studies of interparietal bones primates were identified [7]. since they were observed in two male skulls and a female skull (0.99%) [14]; the In Murphy's study, it was revealed difference was not specific, so sex is that there are four types of pterion: excluded in this work to have accurate and sphenoparietal, frontotemporal, stellate comparable data. Regarding the presence and epipheric [8]. The epiderid bones of metopism, ossicles in the skull and (wormianos) are small and irregular, sutural abnormalities, this may be formed due to additional centers of associated with other cranial deformities ossification near the sutures lambdoidea, and justifies a meticulous clinical pterión and asterión. These Wormian approach that should not be forgotten in bones, epipteric or also called Inca bones, order to identify the differences between a are markers of various diseases, being current human being and an old one [15]. important in the primary diagnosis of The presence of the sutural bone in the osteogenesis imperfecta, and of may be due to the appearance of neurocranial variables that can be an abnormal ossification center [16], deceptive in the diagnosis of fractures [9]. linked to the prehispanic cultures of humans of that time; makes clear the To study the morphologies of the differences between the bilateral pterion, we must take into account the symmetry of the lines that form the current studies such as those of Praba and pterions [17]. Venkatramaniah in 2012, in which they describe that the variants regarding the The study of the Pterion currently types of pterion are due to some factors continues to have a significant importance such as sex, age, ethnicity and the state in since it is a craniometric point that is which the skull is examined; these related to several structures in the cranial variations usually appear in relation to the cavity, such as the anterior branch of the way in which the bones come together and middle meningeal artery, the Broca area, form the region of the pterion. Praba and the insula and the stem of the lateral Venkatramaniah classify the pterions in groove. [18]; its location and frequency is frontotemporal, sphenoparietal, epipheric the basis for surgical interventions; there and stellate [10]. are ancient studies, such as the case of Murphy's original work, in which they On the other hand, a more recent worked with 400 Australian aborigine study in human skulls reveals that the most skulls to establish location and the 4 types common form of the pterion is that of a of pterion, taking into account their sphenoparietal joint, with an incidence of provenance and purity of race [19]. To Murrieta S, Tejada CA, Arriola LE. Rev Mex Med Forense, 2018, 4(2):12-23 complement these studies it is explained Public Ministry of Lima, Peru, with which that the sutural obliteration is involved in the university maintains an agreement and the location; it is assumed that there is a therefore no ethical vulnerability exists. genetic predisposition (genes that allow Likewise, it should be noted that the the formation of secondary ossification personal data of the corpses were not centers) and that are under identified; these counted with the direct genetic control regardless of the permission granted by the Institute of presence or absence of detectable cultural Legal Medicine and Forensic Sciences; deformation [20]. confidentiality was assured with the management of the results, which gave METHODS evidence of the total sample taking under the supervision of a forensic specialist. The study sample consisted of 90 corpses of cadavers that entered the The 90 skulls were evaluated Institute of Legal Medicine and Forensic bilaterally (180 sides); to demonstrate the Sciences, each of which presented as data, results, a photographic record was taken. their background and RENIEC record Data for each evaluated side were (National Identity Registry); for compiled in a data collection form classification purposes, sex, age and place designed by the researcher with the of origin were taken into account; these approval of the advisor. For each case, the data were taken under criteria of most prevalent morphology of the pterion confidentiality and anonymity for each was identified for each side in the skulls of corpse, not having to request an informed the corpses, using the classification of consent from the family member, since the Murphy (1956); the degree of sutural corpse, upon being admitted to the obliteration at the level of the bones that Institute of Thanatology, is under the make up the pterion was also classified, responsibility of the state; there was no using the System of the ectocranial data vulnerability or human integrity. obliteration of sutures according to Meindl & Lovejoy (1985) and White (2000), as After having passed the reviews by well as the average distance of the the established adviser and jury and after ossification center of the pterion. with the having received the resolution for back part of the zygomatic arch; for the execution, the research project was carried measurement an ABFO rule was used and out in the scheduled months; the study it was recorded in millimeters in the file. group consisted of corpses of the Forensic The data were taken during the necropsy Tanatological Division, belonging to the of law for each corpse (figure 1).

Figure 1. On the left side, photographs of the bilateral analysis of the pterion morphology; on the right side, Pterion types according to the Murphy Classification. Source: Own file

For the photographic shot, the morphology per evaluated side; For the camera authorized by the Institute of Legal distance analysis, the Student's T test for and Forensic Medicine of Lima, Canon paired samples was used, providing a level Reflex brand, previously calibrated to a of significance of 0.05. gradual ISO of portrait shot, under the supervision of a forensic specialist, was RESULTS used. The taking of the area of the pterion per hemispherical was carried out together The morphology of the pterion was with the metric witness (ABFO rule), studied in 90 skulls (180 evaluated sides), which served as a reference guide to the as well as the average distance between the measurements of the main anatomical ossification center of the pterion and regions. The data collection was finalized specific bone reference points (posterior and all the data collection, analysis of part of the zygomatic arch). results and conclusions files were studied. Table 1 shows the 4 types of The analysis was carried out pterion; the most frequent type of pterion through the statistical program SPSS was sphenoparietal (70% of cases). version 22.0. The presentation of the Regarding the prevalence of the types on results was started in tables with the evaluated side, it is evident that descriptive summary measures (mean and between the sphenoparietal and standard deviation) for the variable frontotemporal pterion types there is a "pterion morphology" in each study side; level of coincidence of 70 and 30%, not then the chi-squared test was used to differing by side or amount studied; as for establish the distribution of the pterion the type of starry pterion it was found in 5- Murrieta S, Tejada CA, Arriola LE. Rev Mex Med Forense, 2018, 4(2):12-23

6% of the amount under evaluation, being the least prevalent and appearing within that range in both sides evaluated.

In Table 2 it can be verified that in presented mathematically, including two all the evaluated cases a degree 3 of sutural intervals in the average measurements in obliteration is evident, resulting in 100% order to establish a percentage and of the cases; there was no difference on the academic relationship; these were also evaluated side. The mean and the standard analyzed bilaterally; These results are deviation for the measurement parameters recorded in tables 3 and 4, expressed in for the grouped ossification center was millimeters.

Table 3 establishes that bilaterally the right side of 32.90 - 40.01 mm and for the sample has a distance of 30.01 - 40.01 the left side it is 35.6 - 40.01 mm, taking millimeters, coinciding in a 100% of total as average and standard deviation data way in the samples. In Table 4, it was 38.70 and + - 1.57 and 38.91 + - 1.32, recorded that the average distance from the respectively. ossification center per evaluated side is for

DISCUSSION specific bone point such as the zygomatic arch, has an important relation with respect The results found in the present to the clinic, used in neurosurgery, study are compatible with various studies anthropology, forensic and legal medicine, previously conducted in other populations in criteria of Human identification with of the world such as Murphy in 1956, unidentified bone remains. Ersoy and Saxena in 2003, Matsumura in 1991, Mwachaka in 2009 and Morales in It is known that there are 2011, there being no reports of this type in differences in the sutural morphology of a Peruvian population. the pterion between the different existing ethnic groups, a fact that is also associated The understanding and knowledge with the genetic and environmental factors of the type, degree of obliteration and of the place of origin of the human being; location of the pterion in relation to a Therefore, the degree of sutural Murrieta S, Tejada CA, Arriola LE. Rev Mex Med Forense, 2018, 4(2):12-23 obliteration was determined, since it is which the author agrees Le Double, who known from multiple studies of age said not knowing if there would be a estimation that the pterion point partially predominance of one sex or the other [23]. obliterates grade 2 and total grade 3 from the age of 25, achieving total obliteration The present study showed that the of individuals older than 40 years [21]; it sphenoparietal pterion type morphology is was evidenced in the study sample that present in 70% in a group of male skulls; 100% presented grade 3, not it was observed in higher prevalence differentiating by age intervals, a bilaterally compared to unilateral; this data difference that when compared with was observed in another study, where Le previous studies may be due to the Doublé found this type of pterion in 90% incidence rate of sphenoparietal pterion of the studied skulls, using the variables of type according to evolutionary bases; it side, sex and ethnic group with the has been shown that the development of presence of suture bones; they found a the bones that make up the cranial vault is statistically significant relationship in in close relation with the growth of the white male individuals and bilaterally, brain and requires interactions between the leaving a specific relationship that in different tissues within the suture of the female samples is evidenced unilaterally cranial vault; the growth of the brain in [24]. human organisms leads to morphological changes in the , causing the According to our results, it can be greater wing of the sphenoid and parietal established that there is a direct to be reunited, which would explain that relationship between the morphological the increase in closure capacity (complete type of sphenoparietal pterion, the male obliteration) is present in the sample of the sex and the white ethnic group worldwide skulls studied, without differentiating their coinciding with the mestizo group of the age. Peruvian population; this aspect can not be determined exactly, since Peru has a very It is also known that sphenoparietal varied population. type pterions appear more frequently in men (85.4%) than in women (71.4%) [22]; The prevalence of the regarding the relationship caused by the frontotemporal type was in second place early obliteration of the suture, the pattern (24.6%), representing a result superior to of the sphenoparietal type pterion shows a that reported in studies conducted in trend with the early dome-cranial growth Australians (7.5%), Turks (3.5%), Indians of the male individuals; this is directly (10%), Japanese (2.6%), Kenyans ( 15%), related to age, with some variation Nigerians (3.36%) and Mexicans (2.35%); according to the ethnic group. these data showed that this type of pterion has a low prevalence among the ethnic In general, an association of these groups of Latin America [25], being able bones with sex is not found in the to relate it to the high migration of white literature; some authors point out that there individuals from other continents to the is no significant relationship between these Peruvian territory; it is known that this variables; it is suggested to continue the type of pterion has a high prevalence in studies in a unanimous group of sex. primates, but not in humans [26], which Cossedu et al. (1979) and Assala & supports the theories of an evolutionary Mbajiorgu (1996), make a statement with Murrieta S, Tejada CA, Arriola LE. Rev Mex Med Forense, 2018, 4(2):12-23 process relating it to the current brain growth of human beings. In addition, the minimal variations obtained in the sutural morphology of the The lowest prevalence was found pterion within the male Peruvian in the stellar type (6.15%), which population represent important data for represents a higher result than other anthropologists, pathologists, doctors and studies done in Australians (1%), Turks forensic odontologists; by comparing them (0%) and Japanese (0.6%); however, it with the different populations of the world was similar to that reported in studies already studied so far, a current record can conducted in Nigerians (5.06%), Mexicans be granted, thus complementing the (4.12%), Kenyans (12%) and Indians analysis in conjunction with the estimation (5%). There was no record of the epipteric of age, sex, ethnic group within human type, a result that differs in its entirety identification during an investigation. from the existing studies, thus evidencing the remarkable variations in frequency of The knowledge of the sutural the suture bones in the pterion between the morphology of the pterion with the different populations; the mechanism of obliteration of it, as well as the verification formation of the suture bones is not of the distance with a cranial anatomical completely understood until now, point offer a great support in the clinical although some link it to the little and forensic field, thus strengthening the development of the brain associated with role of the current forensic dentist in his environmental or genetic factors [27]. role with the human identification; in Peru there are cases of alleged Human Rights In previous studies, it has been violations even in research and over time reported that the pterion is at an exact most are fragmented and skeletonized, location at 30.35 +/- 3.40 mm and 30.34 + scattered, finding them in parts; through -4.34 mm above the midpoint of the the cranial analysis of Pterion we can study zygomatic arch on the right and left sides, its morphology and degree of obliteration, respectively [26]. Men presented a pterion in order to estimate the age and establish statistically superior in comparison with the ethnic group, primordial indicators in women, being of 39.31 + 3.28 mm and the process of human identification; the 37.35 + 2.97. Therefore, in the present bone rest most found during an study we seek to directly relate this exhumation is the skull and having the location in a Peruvian population, only pterion as a sutural craniometric structure with the male sex [28]; the results obtained with greater anatomical protection, a show a great similarity (100% coincidence sutural morphology without changes over for both sides evaluated), registering a the years is evident. maximum measure of 40 mm on average, thus placing a record for the right side of It is a novel technique, little known 32.9 - 40.01 mm and for the left side of 35. and with good results, so it was decided to + -40.01 mm; these values can be used as carry out the research in 90 Peruvian skulls a guide to any future study of pterion in order to determine the effectiveness of morphometry. In the Peruvian skulls of our the technique in the estimation of sample, the sphenoparietal pterion type adulthood, ethnic group and determination had the highest prevalence (70%), of sex, according to its morphological followed by the frontotemporal (26%) and analysis. With this, we can establish the the stellate (4%). following conclusions: Murrieta S, Tejada CA, Arriola LE. Rev Mex Med Forense, 2018, 4(2):12-23

3. Ilknur A, Mustafa K. I, Sinan B. A 1. Pterion with the highest prevalence comparative study of variation of in a Peruvian population was the the pterion of human skulls from sphenoparietal type with a 13th and 20th century Anatolia, percentage of 70%, followed by Int. J. Morphol. 2009;27(4):1291- the frontotemporal with 26%, there 1298. being no morphological 4. Toshio M. Análisis Morfológico differences in the bilateral study; del Pterion en la Género Alouatta, finally, the type of pterion that Kyoto University overseas obtained the lowest prevalence was research reports of new world the starred type with 6% and no monkeys. 1984; 4:35-37. data of the epipteric type was 5. Natekar PE, DeSouza FM, Natekar found. SP. Pterion: An anatomical 2. Grade 3 sutural obliteration was variation and surgical landmark. found with greater prevalence in Indian Journal of Otology. 2011; the bilateral evaluation of the male 17:2. skull, without distinction of age 6. Walulkar S, Dehankar R, Walulkar interval. M, Ksheersagar DD. Pterion 3. The distance grouped according to formation and its variations in the bilaterally evaluated side of the Human Skull in Vidarbha Region. pterion taking into account the J Cont Med A Dent. 2016; 4(2):4- ossification center with the 10. zygomatic arch is 40 millimeters (4 7. Nambi G. Investigating Pterion centimeters); This is measured from Two Perspectives: vertically. Phylogenetics and Biomechanics 4. The average distance of the WWU Masters Thesis Collection. ossification center of the pterion in 2017; 580. male individuals is for the right 8. Sathessha-Nayak B. Unusual side 32.9 -40.01 mm and for the Sutural Bones at Pterion. left side of 35.6 -40.01 mm. International Journal of Anatomical Variations. 2008; REFERENCES 1:19–20. 9. Ruiz C, Souza G, Scherb T, 1. Morales R, Aguilar M, Elizondo R, Nascimento S. Anatomical Guzman S. Estudio Morfológico variations of pterion: analysis of del pterion y en cráneos the possible anatomical variations adultos mexicanos. Rev Arg de of pterion in human skull. J. Anat Clin. 2011;3(2):77-83. Morphol Sci. 2016; 33(4):200-204. 2. Kalthur SG, Vangara SV, Kıruba 10. Natekar PE, DeSouza FM, Natekar L, Dsouza AS, Gupta C. Metrical SP. Pterion: An anatomical and non-metrical study of the variation and surgical landmark. pterion in South Indian adult dry Indian Journal of Otology. 2011; skulls with notes on its clinical 17:2. importance. Marmara Medical 11. Lee U, Park D, Kwon S at cols. Journal. 2017; 30:30-39. Morphological analysis of the pterion in Korean. Korean J Phys Anthropol. 2001; 14: 281-289. Murrieta S, Tejada CA, Arriola LE. Rev Mex Med Forense, 2018, 4(2):12-23

12. Oguz O, Sanli S, Boskir MG. The of skeletal age at death: a method pterion in Turskish male skulls. and blind test of is accuracy. Am J Surg Radiol Anat. 2004; 26:220- Anthropol. 1985; 68: 1-14. 224. 21. Berry AC, Berry RJ. Epigenetic 13. Eboh DE. Obaroefe M. variation in the human cranium. J. Morphometric study of pterion in Anat.1967; 101(2):361-79. dry human skull bones of 22. Testut L, Latarjet A. Tratado de Nigerians. Int. J. Morphol. anatomia humana. 9ª ed. 2014;32(1):208-221. Barcelona, Salvat, 1969. 14. Pal GP. Variations of the 23. Le Double AF. Traité des interparietal bone in man. Journal variations des os du crane de Anat. 1987; 152:205-208. l'homme. Paris, Sarvier, 1903. 15. Das S, Suri R, Kapur V. 24. Braga MTT, Gabrielli C, De Souza Anatomical Observations on os A, Rodriguez CF, Marino JC. inca and associated cranial Sutural bones in the pterion. Rev deformities. Folio Morphol. 2005; Chil Anat. 2000; 8:1. 84:118-121. 25. Mouri T, Analisis morfológico del 16. Saxesa SK, Chowdhary DS, Jain pterion en el género Alouatta. SP. Interparietal bones in Nigerian Reports of New world Skulls. J Anat. 1988; 144:235-237. monkeys.1984; 4: 35-37. 17. Saxesa SK, Chowdhary DS, Jain 26. Cossedu GG, Floris G, Vona G. SP. A comparative study of pterion Sex and Side Differences in The formation and its variations in the Minor Non-Metrical Cranial skulls of Nigerians and Indians. Variants. J. Hum. Evol.1979; Anthropol. Anz. 1988; 48:75-82. 8:685-92. 18. Ell Najar M, Dawson GL. The 27. Asala SA, Mbajiorgu FE. effect of artificial cranial Epigenetic variation in the nigerian deformation on the incidence of skull: sutural patterns at the Wormian bones in the lambdoidal pterion. East. african. med. J. 1996; suture. Am. J Phys, Anthropol. 73:484-6. 1977; 48: 155-160. 28. Henriquez-Pino J, Buarque LC, 19. Murphy T. The pterion in the Prates JC. Anatomical Study Of Australian aborigine. Am.J. Phys. Sutural Or Fontanellar Bones In Anthropol. 1956; 14:225-244. 200 Brazilian Individuals Skulls. 20. Lovejoy C, Meindl R, Mensforth R Rev. Chil. Anat. 1992; 10(2):89- et al. Multifactorial determination 95.

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