Awad et al. Egyptian Journal of Radiology and Nuclear Medicine (2020) 51:150 Egyptian Journal of Radiology https://doi.org/10.1186/s43055-020-00272-5 and Nuclear Medicine RESEARCH Open Access Role of multi-detector CT in analysis of the greater and lesser palatine foramina Ahmad Sayed Awad1* , Hadeer Maher Ahmed Tohamy2, Hanan Nabieh Gadallah2, Mohamed Emad El-Din Ibrahim2 and Tarek Ahmed Raafat3 Abstract Background: The objective of this study was to assess variation in number, size, shape, and location of greater and lesser palatine foramina using multiple anatomical landmarks through data obtained from adult head CT scans. CT skulls of 200 adult persons were included in this study. There were 100 males and 100 females, aged from 22 to 65 years old. An e-film DICOM viewer version 2 was applied to estimate morphological parameters and to calculate the linear measurements related to the greater palatine foramen. Results: On the basis of CT findings, regarding the position of GPF in relation to maxillary molar teeth, the most frequent location was opposite the third maxillary molar (41%). Regarding the dimensions of the GPF, the mean AP diameter was 3.94 ± 1.13 mm on the right side and 4.22 ± 1.21 mm on the left. The mean LM diameter was 2.17 ± 0.59 mm on the right side and 2.28 ± 0.74 mm on the left. It was concluded that the GPF was AP elongated in 90.5% and circular in 9.5% of the examined CT scans. Linear measurements from the center of GPF to surrounding anatomical landmarks were done and showed no statistically significant difference existed between sides, but a statistically highly significant difference existed between males and females. Conclusions: Proper localization of GPF is important to facilitate therapeutic, local anesthetic, and surgical manipulation in the maxillofacial region. Based on CT findings, we demonstrated that the GPF is most often located opposite the M3 in the majority of the cases. The maxillary molars are the best landmarks for locating the GPF. Keywords: Greater palatine foramen, Location, CT Background fossa, passes through the greater palatine canal, and The hard palate presents many important features in- emerges from GPF in palatal aspect of the third maxil- cluding the greater and lesser palatine foramina. The lary molar, to reach the hard palate [2]. The palatine lesser palatine foramina (LPF) transmit lesser palatine crest is a prominent bony ridge extending medially from vessels as well as middle and posterior palatine nerves. behind GPF [3]. The greater palatine foramen (GPF) transmits greater Locating the greater palatine foramen is of paramount palatine nerve and vessels. Greater palatine nerve is a importance for both dentists and oral and maxillofacial branch of maxillary division of trigeminal nerve supply- surgeons [4]. Furthermore, it is important to determine ing mucosa of hard palate, medial wall of maxillary the location of the GPF for palatal donor tissue and sinus, and posterior aspect of lateral wall of nose [1]. greater palatine nerve block anesthesia. Knowing the The greater palatine artery originates from descending exact location of the GPF is essential also for palatine branch of maxillary artery in the pterygopalatine mobilization of the greater palatine artery in closure of oroantral fistula using mucoperiosteal pedicled palatal * Correspondence: [email protected] flaps [5]. It is also reported that stimulation of pterygo- 1Department of Diagnostic and Interventional Radiology, Kasr Al Ainy Faculty palatine ganglion through this foramen is used for of Medicine, Cairo University, Cairo, Egypt diminishing the effects of paralysis in paralytic patients Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Awad et al. Egyptian Journal of Radiology and Nuclear Medicine (2020) 51:150 Page 2 of 14 and also in cases of cerebral vasospasmor cluster and Morphological parameters migraine headache [6]. The objective of this study was to assess variation in 1. Number of lesser palatine foramina on both sides. number, size, shape, and location of greater and lesser 2. Presence of palatine crest on both sides. palatine foramina using multiple anatomical landmarks 3. Location of the GPF in relation to maxillary molar through data obtained from adult head CT scans. teeth. The location of GPF was described as either opposite the second maxillary molar (M2), between Methods M2 and M3, opposite M3, or behind M3. CT skulls for examination of the brain or paranasal sinuses of 200 adult persons were included in this study. There were The location of the GPF were determined by the 100 males and 100 females, aged from 22 to 65 years old. following steps: Inclusion criteria: CT skulls for examination of brain a. The screen was divided on the e-film viewer into or paranasal sinuses of adult persons of both sexes. two parts (A and B). Exclusion criteria: radiographs showing pathological b. The same axial cuts were retrieved in both parts. changes in the region of maxilla (including c. A transverse line passing through the center of GPF developmental and traumatic changes). in image B was drawn. d. Another line parallel to the first one was drawn in This study was approved by the Research Ethics Com- image A. mittee. Written informed consent was obtained from all e. A new depth of axial reconstruction demonstrated the study patients before any data or scans were gath- an overlap between the previous two lines, thus ered or performed. locating the GPF in relation to maxillary molar A high-speed GE FX CT scanner (GE Healthcare) ac- teeth. quired CT images at exposure 120 kV, 74 mA, 60 mAs; ro- tation time 0.5; and slice thickness 0.mm. Morphometric parameters Patient’s sex and age data were acquired from patient files. The dimensions of the GPF were estimated as follows: An e-film DICOM viewer version 2, a program for radiograph analysis and measurement, was applied to es- a. The longest anteroposterior (AP) and lateral-medial timate morphological parameters and to calculate the (LM) dimensions were measured. linear measurements. Images were evaluated in axial, b. The center of GPF was set at the point of coronal, and sagittal planes. intersection of the longest AP and LM dimensions. Fig. 1 A CT scan at the region of hard palate illustrating the greater and lesser palatine foramina as well as the presence of palatine crest on both sides Awad et al. Egyptian Journal of Radiology and Nuclear Medicine (2020) 51:150 Page 3 of 14 Fig. 2 A CT scan at the region of hard palate illustrating the right and left greater palatine foramina (b) located opposite the right and left third maxillary molars (M3) (a) c. The shape (or form) of GPF was determined by 5. Center of opposite GPF. dividing AP by LM dimensions: Values equal to one indicate a circular foramen Statistical study Values greater than one indicate an AP Statistical analysis was performed using statistical elongated foramen package for social sciences (SPSS) version 21.0 (IBM Values less than one indicate a LM elongated corporation, Somers, NY, USA) statistical software. foramen The frequency of nominal data was done. The associ- ation among the different nominal variables regarding Measurements on CT scans were obtained from the side and gender was explored using Chi square (X2) center of GPF to: tests. The quantitative data were expressed as means ± 1. Posterior border of hard palate (PBHP) (shortest standard deviation (SD). The data were examined by distance). Kolmogorov Smirnov test for normality. Independent t 2. Midline maxillary suture (MMS) (shortest test was performed to compare between the different perpendicular distance). variables regarding side and gender. 3. Posterior nasal spine (PNS). The results were considered significant at p value ≤ 4. Center of incisive fossa (IF). 0.05 and highly significant at p value ≤ 0.01. Fig. 3 A CT scan at the region of hard palate illustrating the right and left greater palatine foramina (b) located behind the right and left third maxillary molars (M3) (a) Awad et al. Egyptian Journal of Radiology and Nuclear Medicine (2020) 51:150 Page 4 of 14 Fig. 4 Bar chart of the frequency of position of the greater palatine (GPF) in CT scans Results Morphological parameters Location of GPF in relation to maxillary molar teeth The presence of one GPF on both sides was a constant finding (Fig. 1). The GPF was most frequently located opposite M3 (41%) (Fig. 2). It was found behind M3 in Table 1 Frequency and percent of position of the GPF based 25.8% (Fig. 3), between M2 and M3 in 23.3%, and oppos- on side ite M2 in 10% (Fig. 4). Regarding the side, on the right Position of GPF Side Total p side, the GPF was located opposite M3 in 40%, behind value Right Left Opposite M3 80 84 164 0.2(NS) Table 2 Frequency and percent of position of the GPF based on gender 40.0% 42.0% 41.0% Gender Position of GPF Total p Opposite M2 20 20 40 value Opposite Between M2 Opposite Behind 10.0% 10.0% 10.0% M2 and M3 M3 M3 Between M2 and M3 48 45 93 Male 8 54 95 43 200 0.3 (NS) 24.0% 22.5% 23.2% 4.0% 27.0% 47.5% 21.5% 100.0% Behind M3 52 51 103 Female 32 39 69 60 200 26.0% 25.5% 25.8% 16.0% 19.5% 34.5% 30.0% 100.0% Total 200 200 400 Total 40 93 164 103 400 100.0% 100.0% 100.0% 10.0% 23.2% 41.0% 25.8% 100.0% Awad et al.