Study to examine diverse locations of greater palatine foramen in dry human skulls

Introduction

Knowledge of human anatomy grants a great understanding about the situation of structures in the human body and provides a better guide for professionals in the health area. 1

In skull, there is presence of various foramina and every foramen passes important anatomical structures. Any deviation from established location may possess great challenges during surgeries involving structures related to these foramina. Greater palatine foramen is one of the foramen, known for its diverse location leading to adversities in dental surgeries.

The hard palate results from the fusion of the palatine processes of the maxilla bones and the horizontal plates of the palatine bones.2 Palatine processes of maxillae bones and horizontal plates of palatine bones fused with each other by cruciform suture.2 Greater palatine foramen is situated in postero-lateral angles of hard palate.3 The foramen transmits greater palatine nerve & vessels.3

The maxillary artery is one of the terminal branches of external carotid artery and is divided into three segments by the lower head of the lateral pterygoid muscle.3 The greater palatine artery arises from the third segment of the maxillary artery and enters into greater palatine foramen alongside the greater palatine nerve.2 The mucous membrane of the inferior meatus of the nose, hard palate, gingivae of the maxillary teeth and nasal septum receive blood supply from the greater palatine artery.4

Among four parasympathetic ganglions of head and neck region, pterygopalatine ganglion is largest parasympathetic ganglion. It is located in pterygopalatine fossa. Greater palatine nerve is a ganglionic branch of maxillary nerve, which passes through pterygopalatine ganglion without relay.2 After entering greater palatine foramen, greater palatine nerve along with greater palatine vessels runs through greater palatine canal up to incisive foramen. It supplies the mucous membrane & glands of hard palate and gingivae of maxillary teeth.2

Knowledge of location of greater palatine foramen is needed to achieve anaesthesia over hard palate & gingivae of maxillary teeth. Diverse locations of greater palatine foramen produce difficulties while performing anaesthesia of maxillary nerve.5

Due to this condition, thorough anaesthesia is not achieved with the use of the maxillary nerve block during various dental surgeries.6 The first explanations about the location of greater palatine foramen were given by Matsuda.7

Most frequent method is used for a maxillary nerve block is via greater palatine canal. Maxillary nerve block through greater palatine canal was first described in 1917 by Mendel.8 A needle is inserted in greater palatine foramen and pushed forward until it is in the inferior part of the pterygopalatine fossa. In pterygopalatine fossa, anesthetic agent is given.9

Our study was undertaken to define the diverse locations of the greater palatine foramen in regards to several anatomical landmarks.

Materials and Methods

The study was performed on 50 dry human skulls. The skulls were obtained from Department of Anatomy, G.M.R.S. Medical College, Gandhinagar. Following observations were recorded in millimeters, using digital vernier caliper:

All measurements were taken bilaterally & directly on dry skulls. After the data collection, data were analyzed through the standard statistically software (SPSS). The mean, standard deviation, minimum and maximum for each measurement were assessed. The t-test was used to confirmthe significant differences between the means obtained from the distances of each antimere of the GPF & reference points.

Result

This study is conducted on 50 dry human skulls procured from designated medical college.

Observations concerning the relative position of the greater palatine foramen to the maxillary teeth are presented in Table 1.

Observations concerning the distance between medial wall of greater palatine foramen & midline palatine suture (MPS) & distance between posterior wall of greater palatine foramen & posterior border of hard palate (PBHP) are presented in Table 2.

Data obtained from statistics analysis suggested no significant difference in the measurement between the right & left sides with regard to the distance of greater palatine foramen (GPF) to the midline palatine suture (MPS) & greater palatine foramen (GPF) to posterior border of hard palate (PBHP).

Table 3 shows t-test comparing the mean of antimeres of each reference point. While there was no statistical difference in distance between GPF and MPS of left and right side but statistical difference was found in distance between GPF and PBHP of left and right side

Figure 1

Illustrates probe in greater palatine foramen

Figure 2

Shows distance between Greater palatine foramen (GPF) & Midline palatine suture (MPS)

Figure 3

Illustrates the measurement of distance from greater palatine foramen (GPF) to Median palatine suture (MPS)

Figure 4

Shows distance between Greater palatine foramen (GPF) & Posterior border of hard palate (PBHP)

Figure 5

Illustrates the measurement of distance from greater palatine foramen (GPF) to Posterior border of hard palate (PBHP)

Discussion

Anaesthesia over hard palate is essential for dental surgery. To achieve that, anaesthetic agent is given in greater palatine nerve. It is essential for the dentists and oral surgeon have knowledge about the location of the greater palatine foramina for periodontal procedures, drainage of abscesses and dental extractions.10 In this study, GPF was localized using easily identifiable marks, according to clinical experience gained during regional anaesthesia procedures.

In Table 4, results of various studies related to position of greater palatine foramen in relation to anatomical landmarks are summarized. Westmoreland & Blanton11 observed 50.70% of GPF were located medial to 3^rd maxillary molar. In the study by Ajmani,12 48.46% of GPF in Nigerian & 64% of GPF in Indian skulls were located medial or opposite of the 3rd maxillary molar. Saralaya & Nayak13 observed 74.6% of GPF were located medial to 3^rd molar. Hassanali & Mwaniki14 observed 76% of GPF (in Kenyan skulls) were located medial to 3^rd molar. In the study of Wang,15 33.5% of GPF (in Chinese skulls) were located medial to 3^rd maxillary molar. In the study of Langengger, 16 62% of GPF were located medial to 3^rd molar. In our study, second most common site of GPF was between 2^nd & 3^rd molar (10%). GPF was medial to 2^nd molar in 8% skulls & it was behind 3^rd molar.

In study of Ajmani,12 the distance from GPF to PBHP was found 3.5mm & 3.7mm in Nigerian & Indian skulls, respectively. According to Westmoreland & Blanton,11 the distance from GPF to PBHP was found 1.9mm, in study of Wang,15 distance was 4.11mm, in study of Saralaya & Nayak,13 distance was 4.2mm, in study of Methathrathip,17 distance was 2.1mm, in study of Jaffar & Hamadah18 distance was 4.86mm, in study of Bruno R. Chrcanovic19 distance was 3.39mm and in study of V. Nimigean20 distance was 4.4mm.

In the study of Westmoreland & Blanton,11 the distance between GPF & MPS on the right side was a mean of 14.8mm & 15.0mm on the left. Ajmani12 reported a distance of 15.4mm from the sagittal plane in Nigerian skulls & 14.7mm on the right & 14.6mm on the left in Indian skulls. Saralaya & Nayak,13 found 14.7mm on both sides. Wang15 found distance between GPF & MPS about 16mm. Methathrathip17 found 2.1mm.

In the study of Jaffar & Hamadah18, Bruno R. & Antônio L.19 and Dave M. R. et al,21 authors have not found any statistical difference between GPF-PBHP and GPF-MPS. In our study, we found statistical difference in distance between GPF and PBHP of left and right side. Although how this statistical difference can contribute clinically is uncertain and future larger studies can further enlighten us about this difference.

Conclusions

In this study, greater palatine foramen was near to 3^rd maxillary molar tooth was found in 25% of the skulls. In regard of distance between GPF-MPS & GPF-PBHP, findings of this study are in line with previous studies except right and left side difference of GPF to PBHP. Diverse locations of greater palatine foramen arouse difficulties in locating exact position during anaesthesia. Therefore, understanding the different positions of greater palatine foramen can help surgeons to improve their surgical procedures.

Source of Funding

Authors of this study declare that present study did not receive any grants or funds from funding agencies.

Conflicts of Interests

The authors declare that they have no conflicts of interests.