American Journal of Primatology 68:777–788 (2006) RESEARCH ARTICLE Arterial Vascularization of the Mandible and Maxilla of Neotropical Primates CRISTIANE SCHILBACH PIZZUTTO1, MARCELO ALCINDO DE BARROS VAZ GUIMARÃES1, AND ARANI NANCI BOMFIM MARIANA2 1 Departamento de Reproduc- ão Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil 2 Departamento de Cirurgia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil The objective of the present investigation was to conduct a comparative macroscopic study of the arterial vascularization of the mandible and maxilla of neotropical primates of the genera Cebus, Alouatta, Callithrix, and Leontopithecus. After vinyl was injected into the arterial system of the head of each specimen, the pieces were macerated and corroded. The level of the bifurcation of the common carotid artery into the internal and external carotids varied between the first and third cervical vertebrae. The external carotid artery accounts for most of the vascularization of the facial structures. The actual vessels responsible for the supply of this region are the sublingual, facial, angular, lingual, submandibular, submental, inferior and superior labial, maxillary, inferior alveolar, infraorbital, superior posterior alveolar, palatine major, and sphenopalatine arteries. We conclude that although the arterial vascular pattern was similar in all the genera studied, and resembles the human pattern, there are notable variations in the vasculature of the mandible and maxilla among these four neotropical genera. Am. J. Primatol. 68:777–788, 2006. c 2006 Wiley-Liss, Inc. Key words: comparative anatomy; neotropical primates; arteries; mandible; maxilla INTRODUCTION Dental health is an important factor in the general well-being of zoo animals [Wenker et al., 1999]. According to Hillden et al.  and Robinson , tooth pain, reduced feeding, body weight loss, and impairment of organic functions due to infections have all been attributed to dental pathologies, including fractures, periodontal diseases, caries, impaction, and tooth retention [Robinson, 1986]. Depending on the severity of the pathology in the affected tooth, adequate treatment should take into account the anatomical structures Contract grant sponsor: Fundac- ão de Amparo a Pesquisa do Estado de São Paulo. Correspondence to: Cristiane Schilbach Pizzutto, Rua Caraı́bas 1342, apto 33, Pompéia, São Paulo, SP, Brazil CEP 05020-000. E-mail: firstname.lastname@example.org Received 2 March 2003; revised 26 September 2005; revision accepted 18 October 2005 DOI 10.1002/ajp.20278 Published online in Wiley InterScience (www.interscience.wiley.com). r 2006 Wiley-Liss, Inc. 778 / Pizzutto et al. where the teeth are inserted. Tooth extraction is often indicated, requiring surgical procedures that are based on an understanding of the vascularization and innervation of the underlying structures. The arterial trunk responsible for the vascularization of the teeth and periodontium in humans is the maxillary artery, which originates from the external carotid artery [Brand & Isselhard, 1994; Serra & Ferreira, 1970; Widdowson, 1952]. This vessel sends out numerous collateral branches along its course. The inferior alveolar artery supplies the teeth and periodontal structures of the mandible, while the superior alveolar and infraorbital branches are responsible for the supply of similar structures in the upper jaw. In view of the lack of information about the vascular anatomy of the head of the brown capuchin monkey, Madeira and Watanabe  carried out a comparative study of the facial arteries of that primate and humans. Veterinary treatments based on data about humans can be problematic when applied to other primates, since the dental structures of nonhuman primates often differ from those of humans. This highlights the need for research involving other primates. Given this scarcity of information, the aims of the present study were to obtain more extensive data from neotropical primates and to describe the vascularization of their mandibular and maxillary periodontal structures. MATERIALS AND METHODS We examined a total of 15 individuals from six species: six brown capuchin monkeys (Cebus apella), two white ear-tufted marmosets (Callithrix jacchus jacchus), three black howler monkeys (Alouatta caraya), one golden lion tamarin (Leontopithecus rosalia), two gold-and-black lion tamarins (L. chrysomelas), and one golden-rumped lion tamarin (L. chrysopygus). All of the specimens were obtained following routine autopsy procedures carried out at Fundac- ão Parque Zoológico de São Paulo. For better conservation of the material, the specimens were immediately frozen after autopsy and kept frozen for about 2 months prior to preparation. After the specimens were thawed, the vascular system was injected as follows: Both the right and left common carotid arteries were cannulated and perfused with physiological saline at ambient temperature, followed by perfusion with acetone P.A. After perfusion the arteries were injected with vinyl acetate (Solvent Vinyl VMCH B-1099; Chemical and Plastic Union Carbide Corp., New York, NY) and stained with Laca Duco Nitrocellulose red (Glasurit do Brasil S.A., São Paulo, SP). About 2 hr later the samples were placed in water for 24 hr for total resin polymerization, and then macerated in water for approximately 2 months. The samples were then incubated in 20% potassium hydroxide for about 2 hr for final corrosion of the remaining soft tissues. The terms used to designate the vessels follow the classification system of the International Human Nomina Anatomica [Feneis, 1976]. RESULTS All results include (whenever possible) the origin, distribution, destination, ramifications, and anastomoses of the vessels, and correlations between these pathways and the bony structures in the left and right sides of the animal’s face. The sample size in this study precluded us from obtaining conclusive evidence of a direct correlation between vessel size and the size of the foramen and/or its accompanying nerve. Am. J. Primatol. DOI 10.1002/ajp Arterial Vascularization of Mandible and Maxilla / 779 Fig. 1. Schematic presentation of a lateral view of the arterial vascular pattern of the mandible and maxilla of Cebus apella (a), Alouatta caraya (b), Leontopithecus sp (c), and Callithrix jacchus jacchus (d), showing the arterial branches: common carotid (c.c.a.), internal carotid (i.c.a.), external carotid (e.c.a.), maxillary (m.a.), inferior alveolar (i.a.a.), facial (f.a.), angular (a.a.), lingual (l.a.), superior labial (s.l.a.), inferior labial (i.l.a.), infraorbital (i.o.a.), mentonian (me.a.), and superior thyroidea (s.t.a.) arteries, linguofacial trunk (l.f.t.), and thyroid-linguofacial trunk (t.t.l.f.). Figure 1 is a schematic presentation of the arterial vascular pattern of the mandible and maxilla of Cebus apella, Alouatta caraya, Leontopithecus sp., and Callithrix jacchus jacchus. Common Carotid Artery We start our description from the bifurcation of the left and right common carotid arteries into their respective external and internal carotid arterial branches. Since vascular patterns are not necessarily bilaterally symmetrical, the left and right sides of each individual were considered separately. We observed variations both within and across species in the location of the bifurcation of the common carotid artery relative to the level of the cervical vertebrae. In capuchins (Fig. 2b), bifurcation was evident in three of 12 samples at the level of the first cervical vertebra, five of 12 samples at the level of the Am. J. Primatol. DOI 10.1002/ajp 780 / Pizzutto et al. Fig. 2. Photograph showing arterial branches of the mandible and maxilla of Cebus apella (a, b, and d) and Alouatta caraya (c). a: Lateral view of the superficial vasculature of the mandible and face of Cebus apella. b: Close-up lateral view of the divisions of the common carotid artery in the cervical region of Cebus apella. c: Close-up lateral view of the retromandibular divisions of the common carotid artery in Alouatta caraya. d: Oblique inferior–superior view of the branching of the external carotid artery in Cebus apella. Note the common carotid (c.c.a.), external carotid (e.c.a.), maxillary (m.a.), facial (f.a.), lingual (l.a.), superior labial (s.l.a.), inferior labial (i.l.a.), infraorbital (i.o.a.), submandibular (s.m.a.), submentonian (s.me.a.), and superior thyroidea (s.t.a.) arteries, and the linguofacial trunk (l.f.t.). second vertebra, and four of 12 at the level of the third vertebra. In all four samples of white ear-tufted marmosets the bifurcation was 0.2 cm superior to the first cervical vertebra. In tamarins the bifurcation was observed at the level of the first cervical vertebra in six of eight samples, and 0.2 cm superior to that point in two out of eight samples. In howler monkeys (Fig. 2c) the bifurcation was observed at the level of the second cervical vertebra in four of six samples, and at the level of the third cervical vertebra in two of six samples. Am. J. Primatol. DOI 10.1002/ajp Arterial Vascularization of Mandible and Maxilla / 781 External Carotid Artery The external carotid artery is one of two branches that originate from the bifurcation of the common carotid artery, and is mainly responsible for the vascularization of facial structures (Fig. 2b–d). Its ramifications are described in detail below according to their importance for the blood supply to the mandible, maxilla, and periodontium. Linguofacial Trunk In all 12 brown capuchin monkey and all four marmoset samples, a common linguofacial trunk was present and originated as the first branch from the external carotid artery (Fig. 2b and d). The superior thyroid artery branched off of the linguofacial truck prior to its bifurcation. The linguofacial trunk was present in all of the lion tamarin samples, with this trunk being the first branch of the external carotid artery. In all four lion tamarins, regardless of species, the right superior thyroid artery was a branch off the linguofacial truck. All the left sides, however, showed a trifurcating thyroidlinguofacial trunk that gave rise to the lingual, facial, and superior thyroid arteries simultaneously (Fig. 1c). No linguofacial trunk was observed in the six howler monkey specimens, with the first three branches of the external carotid artery arising separately as the superior thyroid, lingual, and facial arteries, respectively (Fig. 2c). The linguofacial trunk, when present, bifurcates into two large vessels–the lingual and facial arteries (Figs. 2b–d, and 3a). The lingual artery gives origin to three branches: the dorsal lingual, deep lingual, and sublingual arteries. The first two not were studied here, since the main emphasis of the present study was the arterial branches of the mandible and maxilla destined to reach the periodontium. Sublingual Artery The sublingual artery originates from the lingual artery and is responsible for the vascular supply to the mandibular gingival on the lingual side. It runs anteriorly along the medial side of the ventral border of the mandible, branching on the floor of the mouth and supplying the mandibular periodontal membrane and bone tissue, and anastomoses with the facial, submental, mandibular alveolar, and inferior labial arteries. In the current study the sublingual artery was present in eight of 12 brown capuchin monkey samples, five of six howler monkey samples, three of four marmoset samples, and all eight of the tamarin samples. Facial Artery The facial artery originated from the linguofacial trunk in all of the brown capuchin (Fig. 2d), tamarin, and marmoset specimens, while in howler monkeys it consistently arose separately from the external carotid artery (Fig. 2c). In all of the animals this artery ran medial to the mandibular angle, hidden by its lower border until it reached the mid-portion of the body of the mandible, when it emerged inferiorly to continue more superficially in the direction of the face, laterally crossing the angle of the mouth (Fig. 2d). From this point on, differences in the trajectory of this artery were observed both between and within species. In the present study the facial artery was found to give origin to five important collateral branches: the submandibular, superior and inferior labial, angular, and submental arteries. These branches differed among the species Am. J. Primatol. DOI 10.1002/ajp 782 / Pizzutto et al. studied (Figs. 2d and 3a). In all of the capuchins, marmosets, and howler monkeys, the facial artery in the mid-region of the body of the mandible gave rise to a branch (the inferior labial artery) that continued on toward the mental protuberance. In these species the facial artery then crossed the angle of the mouth, where it gave origin to the superior labial artery. There were numerous anastomoses of the facial artery, especially with vessels on the opposite side of the face and neck, with particular emphasis on the labial ones. In four of 12 capuchin samples, the facial artery ran superior to the angle of the mouth, traversing the side of the frontal process of the nose and ending in the medial commissure of the eye (where it is called the angular artery). Angular Artery The angular artery, when present in capuchin, marmoset, and howler monkeys, is the terminal part of the facial artery (Fig. 1a, b, and d). It ascends to the medial angle of the eye and anastomoses with branches that are not described in this work. In contrast, a double facial artery was observed in all of the tamarin samples (Figs. 1c and 3a). Two main branches are sent out from its origin in the linguofacial trunk. One runs approximately 0.5 cm below the condylar and coronoid processes of the mandible on its lateral side, passing inferior to the zygomatic bone, continuing on the side of the frontal process of the nose, and ending in the medial commissure of the eye. Here it is called angular artery and gives origin to some supraorbital branches above the supraorbital margin. The other main branch of the tamarin facial artery follows the description of the facial artery of the other animals, and ends in the superior and inferior labial arteries. It should be noted this dual facial artery was present only in tamarins, and was consistent in all eight specimens. Submandibular Artery This artery was considered only as an important branch of the facial artery (Fig. 2d) and was present at a frequency equal to that of the submental artery described below. Submental Artery This vessel was found to originate from the facial artery close to the middle of the body of the mandible in all of the samples (Fig. 2d). It runs to the symphysis of the chin and anastomoses with the sublingual artery. It then ascends above the border of the mandible and divides into a superficial branch and a deep branch that connect with the inferior labial and mental arteries, respectively. We identified this artery in 10 of 12 brown capuchins, five of six howler monkeys, two of four marmosets, and seven of eight tamarin samples. It should be noted that when present the tamarin submental artery had an extremely wide caliber and contained numerous tiny ramifications. Inferior Labial Artery This vessel originates close to the angle of the mouth, continuing in a winding manner until the base of the mandible above the mental protuberance (Figs. 2a and 3a), where it anastomoses with the artery of the opposite side and with the mental branch of the inferior alveolar artery. Some branches of the inferior labial artery extend up to the inferior border of the mandible, connecting Am. J. Primatol. DOI 10.1002/ajp Arterial Vascularization of Mandible and Maxilla / 783 Fig. 3. Photograph showing arterial branches of the mandible and maxilla of Leontopithecus sp (a) and Cebus apella (b–d). a: Lateral view of superficial vasculature of head of Leontopithecus sp. b: Hard palate of Cebus apella, showing the greater and lesser palatine arteries. c: The mandibular canal and incisive arteries are exposed as they traverse the body of the mandible in Cebus apella. d: The posterior superior alveolar artery as it traverses the maxillary sinus of Cebus apella. Note the facial (f.a.), angular (a.a), superior labial (s.l.a.), inferior labial (i.l.a.), infraorbital (i.o.a.), mentonian (me.a.), greater palatine (g.p.a.), lesser palatine (l.p.a.), inferior alveolar (i.a.a.), and superior posterior alveolar (s.p.a.a.) arteries. with the sublingual and submental arteries. In 11 out of 12 of the capuchin samples, the inferior labial artery originated 1.5–2 cm anterior to the angle of the mouth, at the level of the mental foramen of the mandible. Superior Labial Artery The superior labial artery is a branch of the facial artery and follows a winding course, continuing anteriorly parallel to the alveolar process of the maxilla inferior to the zygomatic bone in the direction of the nose and upper lip (Figs. 2a and 3a), where it anastomoses with the infraorbital artery and the arteries of the opposite side. As observed for the inferior labial artery, the superior labial artery originated 1.5–2 cm in front of the angle of the mouth in 11 of the 12 brown capuchin samples. In contrast, this artery was very thin and tended to disappear in all Am. J. Primatol. DOI 10.1002/ajp 784 / Pizzutto et al. howler monkey samples. In tamarins, the only interesting difference between the inferior and superior labial arteries was the caliber of the latter. The superior labial artery was much thicker and showed a larger number of ramifications, as well as anastomoses with the angular artery. Maxillary Artery (Arteria maxillaris) This vessel was responsible for the blood supply to the deep facial structures in all of the animals and was the main terminal branch of the external carotid artery (Fig. 2b and d). It ran medial to the respective condylar and coronoid processes of the mandible, from which point it continued medially up to the pterygopalatine fossa. At the anterior end of the pterygopalatine fossa the maxillary artery emits two branches at almost the same point: the infraorbital and posterior superior alveolar arteries. After these ramifications, the descending palatine artery branches off the maxillary artery. The sphenopalatine artery is the real terminal branch of the maxillary artery and passes across the back of the nose to the nasal septum. Inferior Alveolar Artery The inferior alveolar artery arose anteriorly close to the origin of the maxillary artery in all samples studied. It penetrated the mandibular canal through the mandibular foramen and continued as an incisive artery within the mandibular canal (Fig. 3c) until it reached the midline anteriorly, providing branches to the incisor and canine teeth and anastomoses with its homologue on the opposite side. The inferior alveolar artery gave off mental branches through the mental foramen in all of the animals, supplying blood to the region of the chin and anastomoses with the submental and inferior labial arteries. The largest number of anastomoses was observed in tamarins. Infraorbital Artery The infraorbital artery represents one of the last branches of the maxillary artery at the anterior end of the pterygopalatine fossa. In all samples studied it was found to run along the sulcus and infraorbital canal through the infraorbital foramen. Within the canal the infraorbital artery gave origin to dental branches to the maxillary teeth, and emerged on the face through the infraorbital foramen in all of the animals (Figs. 2a and 3a). Posterior Superior Alveolar Artery The posterior superior alveolar artery originates from the maxillary artery and is almost always associated with the infraorbital artery when the vessel trunk passes through the pterygopalatine fossa. Descending along the maxillary tuberosity, it divides into numerous branches, some of which penetrate the alveolar canals in order to supply blood to the molar and premolar teeth (Fig. 3d), and to the lining of the maxillary sinus, whereas others continue anteriorly to the alveolar process to irrigate the gingivae. It was not possible to observe all of the branches sent out to the teeth. Am. J. Primatol. DOI 10.1002/ajp Arterial Vascularization of Mandible and Maxilla / 785 Anterior Superior Alveolar Artery The anterior superior alveolar artery is a continuation of the posterior superior alveolar artery. It is responsible for the blood supply to the canine and incisor teeth through the alveolar branches that descend along the anterior alveolar canals to irrigate incisors, canines, and the mucosal membrane of the maxillary sinus. Descending Palatine Artery The descending palatine artery is another branch of the maxillary artery at the anterior end of the pterygopalatine fossa. It continues through the pterygopalatine canal, emerging at the greater palatine foramen, and gives origin to two collateral branches (the greater and lesser palatine arteries). Lesser Palatine Artery The lesser palatine artery arises from the descending palatine artery in the pterygopalatine canal and descends through the lesser palatine foramen to supply the soft palate (Fig. 3b). Greater Palatine Artery The greater palatine artery is the main arterial vessel responsible for the vascularization of the hard palate. This artery originated from a direct continuation of the trunk of the descending palatine artery after it emerged from the greater palatine foramen in all of the samples studied. It ran anteriorly in the palatine sulcus on the medial side of the alveolar border of the hard palate to the incisive canal (Fig. 3b). Some branches were found to be distributed to the gingiva and the mucosal membrane of the roof of the mouth. Posterior to the incisor teeth, it anastomosed with its homologue on the opposite side, thus forming an arterial arch. Small branches arose from this arch supplying the mucosa, teeth, and periosteum. A terminal branch anastomosed with the nasopalatine branch of the sphenopalatine artery in the incisive canal. In eight of the 12 capuchin samples, the greater palatine artery sent out a wide-caliber branch that continued until it reached the alveolar process of the incisor teeth. This branch was also highly ramified. In two of the 12 samples, this ramification of the greater palatine artery emerged from the greater palatine foramen and continued in the direction of the choanae. Sphenopalatine Artery The sphenopalatine artery is a direct continuation, and thus the terminal branch, of the maxillary artery. It penetrates the nasal cavity after it passes the sphenopalatine foramen and anastomoses with the branches of the greater palatine artery. DISCUSSION The preservation of exotic species requires adequate knowledge about the health of these animals in captivity. It is necessary to provide good dental care for such animals [Wenker et al., 1999], since ignorance can result in severe problems, including loss of appetite, body weight loss, and impairment of organic functions through the occurrence of infections [Hillden et al., 1989; Robinson, 1986]. Am. J. Primatol. DOI 10.1002/ajp 786 / Pizzutto et al. It has long been known that the teeth play an important role in mastication and that therefore their preservation is fundamental for survival. Tooth extraction requires a refined knowledge about the anatomical structures, particularly the vessels and nerves, in the region. Extraction often provokes vascular alterations in the mandibular and maxillary branches, as demonstrated by Castelli and Nasjleti  in rhesus monkeys. In primates the main blood supply to the head comes from the common carotid artery, which bifurcates into external and internal carotid arteries. The external carotid artery is responsible for supplying the most extracranial structures of the head and neck. Therefore, we started our discussion with the bifurcation of the common carotid artery in these different species. Since we used a technique that preserves only bony structures and resin-filled vessels, the reference to soft structures (e.g., muscle and cartilage) was lost; however, this method permitted us to establish direct relationships with bony landmarks in the head. Bugge  showed in his study of the cephalic pattern of supply in diverse mammals that primates can be allocated into different levels of development within an expanded primate order, thereby expressing the order in which the groups in question are presumed to have departed from a line of development that leads from protoinsectivores to anthropomorphs (including humans). The level of the bifurcation of the common carotid artery into the internal and external carotids showed significant variation in previous studies of primates. In chimpanzees, Sperino  observed the same pattern as that found in humans, i.e., bifurcation occurring at the thyroid cartilage level. In studies of baboons [Krieger, 1982], rhesus [Castelli & Huekle, 1965; Dyrud, 1944], and gorillas [Raven & Hill, 1950] the bifurcation was observed more cranially, near the hyoid bone. In the present study, the bifurcation of the common carotid artery was observed at an even higher level, ranging from above the first to the third cervical vertebra. In most primates the facial artery normally emerges in a common trunk with the lingual artery [Castelli & Huelke, 1965; Hill, 1960, 1962; Krieger, 1982; Livini, 1903; Madeira & Watanabe, 1978]. Hill  did not mention the presence of a linguofacial trunk in the genus Alouatta, which confirms the findings of the present study that the external carotid artery dorsally sends out separate lingual and facial arteries. The present results also show that howler monkeys (Alouatta caraya) do not possess a linguofacial trunk, in contrast to the findings of Madeira and Watanabe . This point may be related to intraspecific variation resulting from the small number of individuals studied in these analyses. The presence of a thyroid-linguofacial trunk, as evidenced by a trifurcation, was observed only in half the animals in the genus Leontopithecus, and never in Callithrix jacchus. However, Madeira and Watanabe  also identified the presence of this trunk in C. penicillata. In Leontopithecus and C. jacchus, when a thyroid-linguofacial trunk was absent the superior thyroid artery was observed to be a branch of the linguofacial trunk. With respect to the facial artery, Hill  reported that in capuchin monkeys it disappeared almost immediately after it crossed the mandibular angle. In a study of the same primate, Madeira and Watanabe  found that this artery crossed the angle of the mouth and gave origin to the superior and inferior labial arteries. They also reported that the facial artery showed a complete trajectory in only 0.5% of the animals in their study, ending in the so-called angular artery at the level of the eyes. In the present study a wide variation Am. J. Primatol. DOI 10.1002/ajp Arterial Vascularization of Mandible and Maxilla / 787 regarding this result was observed, with four of the 12 brown capuchin monkeys possessing an angular artery. No reports are available in the literature concerning the facial artery in Leontopithecus. Our results show that these animals have a double facial artery of the same origin. The angular artery of these animals continues on the side of the frontal process of the nose and ends in the medial commissure of the eye, and was identified in all the samples studied. Previous studies of capuchin monkeys [Madeira & Watanabe, 1978] and rhesus monkeys [Castelli & Huelke, 1965] reported that the superior and inferior labial arteries are ramifications of the facial artery. Our results are in agreement with those findings, with the frequency of the inferior and superior labial arteries being 94.7% in the study of Madeira and Watanabe , and 11 of 12 in the present investigation on brown capuchin monkeys. Of interest, we observed that the superior labial artery in howler monkeys was very thin and almost disappeared. Given the presence of such reduced alveolar processes in the maxilla, we believe that the branches of the superior labial artery have practically no bone surface available to perform their anastomoses. With respect to tamarins, the only interesting difference was the greater thickness of the superior labial artery compared to the inferior labial artery. This variation was also observed by Madeira and Watanabe  in capuchin monkeys. According to Serra and Ferreira , the arterial trunk responsible for the vascularization of the teeth and periodontium in humans is the maxillary artery (A. maxillaris). This finding is in agreement with our results, since the branches of this artery were found to irrigate the deep facial structures. Grassé  reported that in capuchin monkeys the maxillary artery ends its trajectory in two branches: the descending palatine artery and the sphenopalatine artery. This observation is in contrast to our findings, which showed that the maxillary artery ended only in the sphenopalatine artery in all of the neotropical primates studied. Cohen  considered the dental arteries to be the main vessels responsible for the nutrition of the mandible. In another study, Cohen  showed that the lower borders of the mandible are mainly supplied by vessels of the periosteum. Subsequently, Castelli  confirmed that the angle of the mandible and its lower borders are irrigated by the inferior alveolar artery. The present study demonstrates that the inferior alveolar artery plays an important role in supplying blood to structures of the periosteum and gingiva in neotropical primates. According to Gray , the greater palatine artery in humans originates from the maxillary artery in the pterygopalatine fossa and descends to the pterygopalatine canal. After it emerges from the greater palatine foramen, it runs anteriorly in a sulcus on the medial side of the alveolar border of the hard palate. That finding differs from the present results in neotropical primates, in that we found the greater palatine artery to be a direct continuation of the trunk of the descending palatine artery after it emerged from the greater palatine foramen. This pattern was also observed by Castelli and Huelke  in rhesus monkeys. Based on the present results, we conclude that the arterial vascular pattern of the maxilla and mandible of neotropical primates is closely similar to that of humans. However, differences among species do exist and should be taken into consideration during dental and/or surgical interventions in captive animals. Bifurcation of the common carotid artery appears to occur at a higher level in neotropical primates as compared to humans, apes, and Old World monkeys. Am. J. Primatol. DOI 10.1002/ajp 788 / Pizzutto et al. Other notable variations in facial vasculature among the neotropical primates were that Alouatta caraya did not possess a linguofacial trunk, a thyroidlinguofacial trunk was frequently observed in the genus Leontopithecus, and the genus Leontopithecus possessed a double facial artery, with the angular artery representing the terminal branch of the more superior of two facial arteries. 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