INTRODUCTION
At the end of the 19th century, the need was recognized to establish an order in the names used to designate anatomical structures, since around 50,000 terms existed to name just over 5,000 anatomical structures (Losardo et al., 2015). In many cases, numerous different terms were used to name the same structure (Cruz & Cruz, 2009). The purpose of anatomical terminology (Terminologia Anatomica- TA) is to ensure clear, precise communication in the medical field, facilitating teaching and learning as well as scientific communication (Duque-Parra et al., 2016). Nonetheless, there are many anatomical structures that have not yet been included in TA, one of which is a vascular structure resulting from anastomosis between the posterior superior alveolar artery (PSAA) and the infra-orbital artery (IOA). The PSAA and the IOA are rami of the maxillary artery and are responsible for irrigating the pulp and the inserting periodontium of the upper teeth; the mucus and the anterior, lateral and posterior walls of the maxillary sinus; the lower eyelid, the nasal ala and the mucous of the upper lip. These arteries have intraosseous and extraosseous rami which form an anastomosis in the lateral wall of the maxillary sinus (Alves & Cândido, 2016).
The anastomosis between the PSAA and IOA was first described in 1934 by Strong, who related that this artery was responsible for irrigating the mucous membrane of the maxillary sinus and adjacent teeth (Taschieri & Rosano, 2010). The clinical importance of this artery is related with the risk of severe intraoperative haemorrhage due to lesions caused during surgical procedures in the region, affecting the surgeon's field of view and thus increasing the risk of perforation of the maxillary sinus (Rahpeyma & Khajehahmadi, 2014). Studies in cadavers indicate that the anastomosis between the PSAA and IOA is always present (Ella et al., 2008), however this vascular structure has not yet been included in TA.
In scientific literature, authors use different anatomical terms to refer to this structure, such as PSAA (Jung et al., 2011; Cruz Ibañez et al., 2016), Intraosseous Ramus of the PSAA (de Oliveira et al., 2017), Intraosseous Rami (Duruel et al., 2019), Intramural Artery (Godil et al., 2021), Alveolar Antral Artery (AAA) (Alves & Cândido; Alves, 2017; Alves et al., 2020), etc. Considering the variety of terms used to name this vascular structure, the object of this study was to carry out a systematic review of the terms used.
MATERIAL AND METHOD
Protocol and registration. The protocol was published in INPLASY, number 202120071.
Eligibility criteria. A systematic review was carried out of the terms used to designate the anastomosis between the PSAA and IOA in imaging studies and studies in human cadavers that assessed the presence/frequency of this anatomical structure. The search was carried out in the Medline, EMBASE and LILACS databases, including ori- ginal studies in Portuguese, Spanish and English. In vitro studies, case reports, theses, letters to the editor and systematic reviews were excluded.
Sources of information. The search was carried out in the Medline, EMBASE and LILACS databases, without date restrictions. In addition, we examined the reference lists of the studies included. The search strategy used in Medline was: ((((((("Cone-Beam Computed Tomography"[Mesh] OR "Spiral Cone-Beam Computed Tomography"[Mesh])) OR CBCT [tiab]) OR Computed Tomography*) OR dissection [tiab]) OR "Dissection"[Mesh]) OR "Cadaver"[Mesh])) AND (((((((((alveolar antral artery) OR intraosseous arterial anastomosis) OR extraosseous arterial anastomosis) OR maxillary sinus vascularization [tiab]) OR maxillary sinus vascular anatomy) AND (((course [tiab]) OR diameter [tiab]) OR anatomy*) OR "Anatomy"[Mesh]) OR Prevalence)
Selection of studies. All references identified were extracted to an EndNote X9 database to facilitate management and delete duplicate articles. Titles and abstracts of studies retrieved using the search strategy were screened independently by two authors to identify studies that potentially met the inclusion criteria. Titles and abstracts were selected using the Rayyan software (http://rayyan.qcri.org). We obtained the full texts of all relevant and potentially relevant studies meeting the inclusion criteria, and those for which there were insufficient data in the title and abstract to make a clear decision. Any disagreement between the two authors was resolved through discussion with a third reviewer.
Data charting process. One reviewer (F.C. or N.F.D) extracted relevant data from eligible studies describing their main characteristics. A second reviewer checked all the extracted information for accuracy (non-independent verification of data extraction). The authors extracted the following information from each article using a standardized, predefined data collection form: Author, year, title, type of study (study in cadaver or imaging study), term used to name the anastomosis between the PSAA and IOA.
Synthesis of the results. Qualitative analysis of the data was carried out, as well as percentage analysis of the terms used. Studies which used more than one term were grouped in the category with the highest percentage. The results were presented in a table.
RESULTS
The search strategy identified 2108 original articles; 123 duplicates were excluded. After review of the titles and abstracts, 60 were selected as potentially relevant and 54 studies were finally included for qualitative analysis (Fig. 1). Forty-seven computed tomography or cone-beam computed tomography studies were included (87.0 %), five studies in cadavers (9.3 %) and two imaging studies and cadavers (3.7 %). Sixteen different terms were used to refer to the same structure in the studies analysed (Table I); the term used most frequently was PSAA (38.9 %), followed by Alveolar Antral Artery (27.8 %) and Intraosseous Anastomosis (9.43 %).
DISCUSSION
The maxillary sinus is a cavity located in the interior of the body of the maxilla; it is directly related with the nasal cavity by its nasal or medial wall, and with the dental alveoli of the posterior superior teeth, especially the molars, by its inferior wall or sinus floor (Alves & Cândido). The discovery of the maxillary sinus is attributed to doctor Nathaniel Highmore, who first described it in his book Corporis Humani Disquisitio Anatomica (Mavrodi & Paraskevas, 2013); for this reason the structure was included in the Nomina Anatomica (NA) as Highmore's Antrum (Wells, 1948). In 1901, years after the inclusion of this term in the NA, sketches by Leonardo da Vinci were discovered, drawn in 1489, which illustrated the maxillary sinus and adjacent structures; however although da Vinci's drawings are the oldest on record, the term Highmore's Antrum had already been included in the NA and was used for many years. Today, since the use of eponyms has been abolished in TA, the term Highmore's Antrum has been reviewed and replaced by the term Maxillary Sinus (Duque-Parra et al., 2016, 2018).
The maxillary sinus is irrigated by the anastomosis between the PSAA, which courses half of the lateral wall of the maxillary sinus intraosseously, and the IOA which courses through the anterior wall of the maxillary sinus (Rosano et al., 2011). This anastomotic circuit is responsible for the vascularization of the sinus membrane, the periostic tissues, and especially the anterolateral wall of the sinus. According to Rosano et al. (2011) the two anastomoses (intraosseous and extraosseous) form a double arterial arch, supplying the lateral wall of the antrum and parts of the alveolar process.
In the present review it was found that the anastomosis between the PSAA and IOA was called PSAA in the majority of the studies analysed, however this term may not be the most appropriate because the artery in question is an anastomosis between the PSAA and IOA, and not the PSAA itself. Almost one third of the authors used the term AAA, showing that this term is widely accepted among researchers and anatomists. Because the anastomosis between the PSAA and IOA irrigates the maxillary sinus, it is possible that the term “antral” is an allusion to Antrum Highmorianum, the original name for the maxillary sinus.
Our findings show that there is great confusion among clinicians and anatomists about how to refer to this vascular structure, since it has 16 names. In view of the fact that this structure is always present, and the diversity of terms used to refer to it, unification of the anatomical term is imperative. We agree with Alves that this structure should be included in TA, facilitating a single term for use among clinicians, anatomists and researchers. The use of a standard anatomical terminology is fundamental for promoting clear, unequivocal communication (Neumann, 2018). This is done by the choice of an appropriate official Latin term, and recognising as synonyms other Latin terms that have been used consistently for the same anatomical structure (Neumann).
Many Symposia of Morphological Terminology (SMT) are held to unify the names applied to structures of the human body, ensure the use of common scientific language, and facilitate learning and communication between professionals (Band, 2006; Losardo et al.). An interesting aspect addressed in these meetings is the discussion of new terms which arise in dissection laboratories or operating theatres, and which are not yet included in TA (Cruz & Cruz). In this context, we believe that it is very important that some future SMT should discuss the inclusion in TA of the most appropriate term to designate the anastomosis between the PSAA and IOA, in order to facilitate teaching and learning and to avoid confusion in scientific communication.
Study limitations. Despite the exhaustive review carried out, there may be studies published in languages other than Portuguese, Spanish or English, which have therefore not been included in our review. Moreover, we did not evaluate the anatomical terminology used in anatomical textbooks or books published for the use of clinicians. A strength of our study is that it shows the numerous forms used to name the anastomosis between the PSAA and IOA, corroborating the need to include this structure in TA.
CONCLUSION
Many terms are used in the medical literature to designate the anastomosis between the PSAA and IOA, the most frequent being Posterior Superior Alveolar Artery and Alveolar Antral Artery. There is a need to unify the terms used to designate this vascular structure, and to incorporate the selected term into anatomical terminology in order to avoid confusion in scientific communication.