European Journal of Cardiovascular Medicine

The horizontal plates of the palatine bone, the pre-maxilla, and the palatine processes of the maxilla combine to form the hard palate, an essential part of the skull. It has an arched structure with varied depth and breadth, is widest in the molar area, and divides the oral cavity from the nasal cavity above [1]. The minor palatine foramina are situated behind the bigger palatine foramen, and both are found in the posterior region of the hard palate [2]. It is widely accepted that palatal  morphology and morphometry play an important role in forensic dentistry. Owing to its position inside the oral cavity, the hard palate is unlikely to be harmed after trauma, which makes it a trustworthy structure for identifying people in situations when the skull has been damaged or decomposed [3]. In forensic and anthropological studies, skull morphometry is also important for establishing age, size, and ethnicity [3, 4]. Procedures like nasal pharyngoscopy, nasogastric intubation, and related instruments require an understanding of the normal anatomical features of the hard palate [5]. To treat orthodontic disorders, orthognathic surgeries, maxillary dental implants, and other treatments, such as cleft palate surgery, palatal morphometry is essential for treatment planning [6]. Accurate hard palate metric measurements are particularly helpful when making dentures and restoring prosthetics for speech and regular function [7-9]. While the hard palate has been studied in the past, the minor palatine foramina and their relationship to surrounding landmarks have not been thoroughly investigated in our region [10-14]. Future research can use the data collected from this study as a baseline in anthropometrics, dentistry, forensic sciences, and anatomy. The present study aimed to measure the morphometric characteristics of the hard palate in dried human skull bone that belonged to the North Indian population.

The present study was conducted on 50 dried skulls obtained from the Department of Forensic Medicine & Toxicology and Anatomy, at Indira Gandhi Institute of Medical Sciences in Patna, Bihar. The age and sex of the skulls were not known.

The inclusion criteria were as follows:

• Only those well-preserved, nonpathological adult skulls were included in the study that had an intact base of the skull, especially the anterior cranial fossa and middle cranial fossa region, and were complete in all aspects, suitable for accurate morphological observations.

The exclusion criteria were as follows:

• Skulls that were extensively damaged, pathological, fragmented, healed fractures, or showed significant deformities affecting the hard palate were excluded from the study.

Figure 1: Hard Palate showing landmarks for measurements.

A digital Vernier caliper with an accuracy of 0.01 mm was used for all measurements. We measured the following morphometry of the hard palate:

1. Length of the hard palate: The distance from the posterior nasal spine posteriorly to the orale anteriorly (From point P to Q as in Figure 1). On the median plane, the orale is the point between the two medial maxillary incisors.
2. Breadth of the hard palate: The distance between the inner edges of the upper second molar sockets (From point R to S as in Figure 1).
3. Height of the hard palate: Height of the palate from the line connecting the endomolaria.
4. Palatine index (PI): The palatine index (PI) was classified using the methods by Hassanali and Mwaniki [15]. PI is the percent ratio of palatine width to palatine length, calculated using this formula:

Palatine index (PI) = Breadth/Length X 100.

Based on the PI measurements the palates were classified as leptostaphyline, mesostaphyline, and brachystaphyline.

Type 1: Leptostaphyline (L): Narrow palate with index ≤79.9%.

Type 2: Mesostaphyline (M): Intermediate palate with index 80-84.9%.

Type 3: Brachystaphyline (B): Wide palate with index ≥85%.

1. Palatine height index (PHI): The following formula was used to calculate the palatal height index:

Palatine height index (PHI) = Palatal height/Breadth X 100.

According to this calculation; the hard palates were classified as follows [15]:

Type 1: Chemostaphyline: Low palate with index ≤27.9 %.

Type 2: Orthostaphyline: Intermediate palate with index 28-39.9%.

Type 3: Hypsistaphyline: High or deep palate with index ≥40 %.

To prevent inter-observer bias, only one observer took all of the measurements. The measurements and data obtained will be useful to clarify the morphometry of the hard palate. Anthropometric research, dental, forensic, and anatomical sciences can use these data.

Statistical Analysis: The Excel 2019 and Statistical Package for Social Sciences (SPSS, version 24.0) were used to evaluate the data that had been gathered. The metric parameters were determined by mean, standard deviation, and range.

The mean palatine length, breadth, and height in the present study were 46.30 ± 3.87 mm, 32.73 ± 2.66 mm, and 11.27 ± 2.03 mm, respectively. The mean values of the palatine index and palatine height index were 71.12 ± 7.80 mm and 34.66 ± 6.79 mm respectively. The most frequent type of hard palate was leptostaphyline (84%), followed by mesostaphyline (12%) according to the palatine index, while brachystaphyline type (4%) was the least commonly reported. While, the most frequent type of hard palate was orthostaphyline (62%), followed by hypsistaphyline (20%) according to the palatine height index, while the chemostaphyline type (18%) was the least commonly reported [Table 1, 2, and 3].

Table 1: Showing different metric parameters and indices of the hard palate

Table 2: Showing the classification of the hard palate according to the palatine index

Table 3: Showing the classification of the hard palate according to the palatine height index

The hard palate's mean length in the current investigation was 46.30±3.87 mm. When compared to earlier studies, the findings of this one were very similar to those of Kaur A. et al. (46.16 mm) [16], D'Souza AS et al. (49.13 mm) [10], Jotania B. et al. (49.73 mm) [11], and Rao MJ et al. (49.87 mm) [12]. In the current study, the mean palatal breadth was 32.73±2.66 mm. This was less than the results of D'Souza AS et al. (40.4 mm) [10], Jotania B et al. (37.75 mm) [11], Shalaby SA et al. (38 mm) [13], and Sarilita E et al. (38.68 mm) [14], but it was comparable to the results of Kaur A et al. (33.01 mm) [16] and Rao MJ et al. (34.42 mm) [12]. Our study's mean palatal height of 11.272.03 mm was in accordance with findings from studies by Sarilita E. et al. (11.8 mm) [14], Kaur A. et al. (11.06 mm) [16], and Shalaby SA et al. (11.5 mm) [13]. Palatal classification showed that 84% of the skulls in this study belonged to the leptostaphyline class, 12% to 

the mesostaphyline class, and 4% to the brachystaphyline class. These findings differed from those of D'Souza AS et al. (37.5% leptostaphyline) [10], Jotania B et al. (70% leptostaphyline) [11], and Rao MJ et al. (95% leptostaphyline) [12], but they were in line with Kaur A et al. (83% leptostaphyline) [16] and Sarilita E et al. (84% leptostaphyline) [14]. Similarly, 62% of the palatal height in the current study was classified as orthostaphyline, 10% as hypsistaphyline, and 9% as chemostaphyline depending on the analysis. While the findings of Sarilita E et al. [14] and D'Souza AS et al. [10] were different from the observations of the current investigation, they were most similar to Shalaby SA et al. [13] and Kaur A et al. [16]. Understanding the palatine index is essential since a high and narrow palate has been linked to numerous disorders, including Apert syndrome, Turner's syndrome, Marfan syndrome, and Franceschetti-Collins syndrome. When the five hard palate characteristics were statistically analyzed using logistic regression, Shalaby et al. concluded that external palate breadth was the best sex determinant [13]. External palate breadth alone was found to be able to correctly classify 66.7% of the sample size, according to Gangrade et al. [17]. In addition, there are applications for the morphometric characteristics of the palate in forensic dentistry. Because the palatal and dental structures are shielded by the oral cavity, they are less vulnerable to heat-related stressors and injuries. This makes it possible to identify specific individuals and estimate their sex even in situations when there has been substantial tissue loss [18,19].

Limitations of the study: The age and sex of the skull bones were not studied as it was not available. Furthermore, the results obtained are specific to the North Indian Population, and hence generalizing the study results requires further research in different ethnicities and geographical areas.

The study's information will be helpful in the fields of anthropometric, dental, and medical sciences. A thorough anatomical knowledge of the hard palate is essential for executing certain surgical treatments in the hard and soft palate, anthropological research, complete maxillary denture fabrication for edentulous patients, and ethnic and racial classification of crania. Oral maxillofacial surgeons may benefit from knowledge of the palatal index when performing surgery to fix a cleft palate or lip.

1. Romanes GJ. Cunningham’s Textbook of Anatomy. 12th ed. New York: Oxford Medical Publishers;1981.
2. Standring S. Gray’s Anatomy. Anatomical basis of clinical practice. 40th Edition., Churchill Livingstone, London; 2008.
3. Iscan MY. Global forensic anthropology in the 21st century. Forensic Science International. 2001;117(1-2):01-06.
4. Harvati K, Weaver TD. Human cranial anatomy and the differential preservation of population history and climate signatures. The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology: An Official Publication of the American Association of Anatomists. 2006;288(12):1225-33.
5. Patel M. A study of the hard palate in the skulls of the central Indian population. Int J Pharm Bio Sci. 2012;3(2):527-33.
6. Caples SM, Rowley JA, Prinsell JR, Pallanch JF, Elamin MB, Katz SG, et al. Surgical modifications of the upper airway for obstructive sleep apnea in adults: A systematic review and meta-analysis. Sleep. 2010;33(10):1396-407.
7. Grave AM, Becker PJ. Evaluation of the incisive papilla as a guide to anterior tooth position. The Journal of Prosthetic Dentistry. 1987;57(6):712-14.
8. Park YS, Lee SP, Paik KS. The three-dimensional relationship on a virtual model between the maxillary anterior teeth and incisive papilla. The Journal of Prosthetic Dentistry. 2007;98(4):312-18.
9. Mustafa AG, Tashtoush AA, Alshboul OA, Allouh MZ, Altarifi AA. Morphometric study of the hard palate and its relevance to dental and forensic sciences. International Journal of Dentistry. 2019;2019:1687345.
10. D’Souza AS, Mamatha H, Jyothi N. Morphometric analysis of the hard palate in south Indian skulls. Biomed Res. 2012;23(2):173-75.