The Palatal Interpterygoid Vacuities of Temnospondyls and the Implications for the Associated Eye‐ and Jaw Musculature

A diagnostic feature of temnospondyls is the presence of an open palate with large interpterygoid vacuities, unlike the closed palate of most other early tetrapods, in which the vacuities are either slit‐like or completely absent. Attachment sites on neurocranium and palatal bones in temnospondyls allow the reconstruction of a powerful m. retractor bulbi and a large, sheet‐like m. levator bulbi that formed the elastic floor of the orbit. This muscle arrangement indicates that temnospondyls were able to retract the eyeballs through the interpterygoid vacuities into the buccal cavity, like extant frogs and salamanders. In contrast, attachment sites on palate and neurocranium suggest a rather sauropsid‐like arrangement of these muscles in stem‐tetrapods and stem‐amniotes. However, the anteriorly enlarged, huge interpterygoid vacuities of long‐snouted stereospondyls suggest that eye retraction was not the only function of the vacuities here, since the eye‐muscles filled only the posterior part of the vacuities. We propose an association of the vacuities in temnospondyls with a long, preorbital part of the m. adductor mandibulae internus (AMIa). The trochlea‐like, anterior edge of the adductor chamber suggests that a tendon of the AMIa was redirected in an anteromedial direction in the preorbital skull and dorsal to the pterygoids. This tendon then unfolded into a wide aponeurosis bearing the flattened AMIa that filled almost the complete interpterygoid vacuities anterior to the orbits. Our muscle reconstructions permit comprehensive insights to the comparative soft tissue anatomy of early tetrapods and provide the basis for a biomechanic analysis of biting performances in the future. Anat Rec, 300:1240–1269, 2017. © 2017 Wiley Periodicals, Inc.     

Variations of the prominences of the bony palate and their relationship to complete dentures in Korean skulls.

The osteological and morphological variations of the prominences in the bony palate of 160 Korean skulls were studied. The frequency of the occurrence of the posterior palatine crest, located on the posterior border of the greater palatine foramen, was 13.8%. Palatal ridges were observed commonly in the skulls; however, the smooth type, which has no palatal ridges in the palate, was shown in 14.7% of cases, and palatal spines were observed in 33.8%. The prevalence of palatal tubercles was 11.6%, and all were found in the molar region. The palatine torus was found in 18.8% of cases and the most common type was along the median palatine suture from the incisive foramen to the posterior border of the palatine bone (63.3%). No significant differences between sexes or sides were found in the posterior palatine crest, palatal ridges, and palatal tubercle. However, the sex distribution of the palatine torus was significantly different (P < 0.05). These results would be helpful clinically in fabricating maxillary complete dentures for edentulous patients.     

Anatomical study of the greater palatine artery and related structures of the palatal vault: considerations for palate as the subepithelial connective tissue graft donor site

Palate is considered as a tissue graft donor site for dental surgical procedures. Therefore, the aim of this study was to investigate the anatomy of palatal structures, such as greater palatine artery, greater palatine foramen, and incisive fossa, in order to consider their topography at planning the graft dimensions and reduce the potential risk of injury of greater palatine artery. Direct inspection of 41 Thai cadavers was performed. The results showed the statistically significant differences as for the length of female and male palates (p = 0.017); however, vertical measurements were equally distributed in examined population. Main location of greater palatine foramen was palatal to the second molar (35.7%), as well as, interproximal to the second and third molars (35.7%) in women, and palatal to the second molar in men (65%). GPA was branching most frequently at the level of first premolar (38%) and at first and second molars together (43%) in women. In men, the branching on the alveolar process side was commonly observed at the level of first and second premolars together (56%), and at the level of second and third molars together (32%). In the area between maxillary first premolar and second molar, it appeared possible to harvest a connective tissue graft measuring at least 5 mm in height. The results of this research will provide the useful data for other comparative studies and for assisting periodontologists in planning the dimensions and harvesting the subepithelial connective tissue grafts from palate.     

Anatomy of greater palatine foramen and canal and pterygopalatine fossa in Thais: considerations for maxillary nerve block

This study aims to investigate the anatomy of the greater palatine foramen (GPF), greater palatine canal (GPC) and pterygopalatine fossa (PPF) with special reference to the blockage of the maxillary nerve. A correlation between the length of GPC and PPF and the heights of the orbit and the maxilla was also studied using simple linear regression analysis. The morphology of the GPF, GPC and PPF as well as heights of the orbit and the maxilla were assessed in 105 Thai skulls. The thickness of the mucosa over the GPF was also measured from the dissection of 55 cadavers. The results showed that most GPF appeared as an oval foramen located at the palatal aspect of the upper third molar. The GPF was 16.2±1.3 mm lateral to the median sagittal plane of the hard palate, 2.1±1.3 mm anterior to the posterior border of the hard palate and 5.1±1.3 mm from the greatest concavity of the distolateral margin of the hard palate. The mean length of GPC and PPF was 29.7±4.2 mm. The mean angles of the GPC in relation to the hard palate and the vertical plane were 57.9±5.8° and 6.7±5.2°, respectively. In attempting to insert a needle to reach the foramen rotundum through the GPF, 31.7% passed into the orbit while 8.7% passed into the brain. The mean thickness of the mucosa over GPF was 6.7±2.3 mm. Two models for estimating the depth of needle injection in maxillary nerve block have been developed as follows: Length of GPC and PPF=19.038+0.314 (orbital height) and length of GPC and PPF=21.204+0.187 (maxillary height). The calculated length combined with the mucosal thickness was the estimated depth of needle injection. In conclusion, our results concerning the GPF, GPC and PPF will provide the useful reference for clinicians to anesthetize the maxillary nerve with a greater degree of success.     

Development and evolution of the notarium in Pterosauria

The notarium is the structure formed by fusion of the dorsal vertebrae which occurred independently in pterosaurs and birds. This ankylosis usually involves two to six elements and in many cases, also includes the last cervical vertebra. Fusion can occur in different degrees, uniting the vertebral centra, the neural spines, the transverse processes, the ventral processes, or a combination of these sites. A detailed assessment of the fusion process of pterosaur dorsal vertebrae is still lacking. Here we identify the fusion sequence of pterosaur notarial elements, demonstrating the order of ossification in vertebral bodies and neural spines based on fossils and extant birds. In both Pterosauria and Aves, the notarium generally develops in a antero-posterior direction, but the actual order of each fusion locus may present slight variations. Based on our data, we were able to identify seven developmental stages in the notarium formation, with broad implications for the prediction of ontogenetic stages for the Pterosauria. In addition, we report the occurrence of a notarium in Ardeadactylus longicollum (Kimmeridgian, Southern Germany), the oldest occurrence of this structure in pterosaurs.     

In Vitro Analysis of Palatal Shelf Elevation During Secondary Palate Formation

Palatal shelf elevation is an essential morphogenetic process during secondary palate formation. It has been proposed that shelf elevation results from an intrinsic elevating force and is regulated by extrinsic factors that are associated with development of other orofacial structures. Although dynamic palate culture is a common in vitro approach for studying shelf elevation, it requires the tongue or the tongue and mandible to be removed before culture, which prevents any determination of the role of the extrinsic factors in regulating shelf elevation. We showed that ex vivo removal of the tongue and mandible from unfixed embryonic heads led to spontaneous shelf movements that were more pronounced at late E13.5 and early E14.5 than those of E12.5 and early E13.5, suggesting that the strength of the elevating force increases over time during palate development. We further used a suspension culture technique to analyze palatal shelf movement in an intact oral cavity by culturing the orofacial portion of embryonic heads that include the maxilla, palatal shelves, mandible, and tongue (MPMT). MPMT explants were cultured in the serum-free medium with slow rotation for 24–48 hr. The palatal shelves successfully elevated during culture and displayed intermediate morphologies that closely resemble those of in vivo shelf elevation. We demonstrate that the tongue and mandible facilitate shelf medial movement/growth during shelf elevation and further suggest that the interaction of the palatal shelves and tongue could be one of the extrinsic factors that regulate the elevation process. Anat Rec, 302:1594–1604, 2019. © 2019 American Association for Anatomy     

腭部恶性肿瘤的CT诊断

探讨腭部恶性肿瘤的CT表现及其诊断价值。回顾性分析32例经病理证实的腭部恶性肿瘤的CT表现,其中男27例,女5例。所有病例均行横断增强扫描,其中8例同时行平扫,2例加冠状位扫描。腭部恶性肿瘤的CT表现为:(1)腭部肿块(26例)、腭部软组织增厚(6例)和腭骨质破坏(6例),其中病变位于软腭(22例)、硬腭(4例)、软硬腭交界处(3例);(2)邻近结构受累及(27例);(3)颈部淋巴结转移(17例)。CT是一种优良的检查技术,能显示腭部恶性肿瘤的大体病理改变以及侵犯途径,为临床治疗和预后提供重要信息。     

Clinical anatomy of the posterior maxilla pertaining to Le Fort I osteotomy in Thais

This article studies the anatomy of the posterior maxilla pertaining to bone-cut design of Le Fort I osteotomy to avoid the injury to the descending palatine artery in Thais. Fifty-five skulls (38 males, 17 females) were assessed for the anatomical landmarks by a combination of direct inspection, computerized imaging, and computed tomography scan analysis. The results showed that 27.28% of the pterygomaxillary junction (PMJ) became synostosis. The mean heights of the PMJ, posterior maxilla, and maxillary tuberosity were 15.14 +/- 2.46 mm, 22.51 +/- 3.50 mm, and 7.45 +/- 2.76 mm, respectively. The mean length of the medial sinus wall measuring from the piriform rim to the descending palatine canal at the Le Fort I level was 34.40 +/- 2.96 mm. The mean widths of the posterior incision of Le Fort I osteotomy at the maxillary tuberosity and PMJ were 20.38 +/- 2.82 mm and 11.60 +/- 1.57 mm. The mean length of the posterior maxilla was 27.18 +/- 2.49 mm. Distances from the greater palatine foramen to the maxillary tuberosity incision and PMJ incision were 1.76 +/- 1.12 mm and 3.59 +/- 1.40 mm. The mean angle between the descending palatine canal and the hard palate was 57.33 +/- 4.54 degrees . There were no significant differences in any measurements between sides and genders, except the pterygoid process width and posterior maxilla length of males were longer than those of females (P < 0.05). This study could provide better understanding of the posterior maxillary anatomy that is important for the bone-cut design of Le Fort I osteotomy to avoid excessive intraoperative and postoperative hemorrhage including ischemia of the mobilized maxilla.     

Blood supply of the human levator and tensor veli palatini muscles

In spite of its clinical importance in cleft palate, there are few detailed accounts of the blood supply of the soft palate and palatal muscles. A series of dissections was carried out to investigate the supply of the levator and tensor veli palatini muscles. Ten adult cadavers and 12 fetuses were used, all of which had been previously injected with a variety of media to outline the vascular tree. Conventional dissection was performed on the cadavers, and microsurgical instruments and a dissection microscope were utilized for fetal dissections. In 70% of dissections the m. levator veli palatini had a dual arterial supply, from the ascending palatine and ascending pharyngeal arteries. In the remainining cases the muscle was supplied by a single artery, either the ascending palatine or ascending pharyngeal. In 79% of dissections the tensor muscle had a dual supply from the accessory meningeal artery along with either the ascending palatine, ascending pharyngeal, or, in one case, the lesser palatine arteries. The results suggest that in careful surgical closure of the cleft soft palate the normal dual arterial supply would protect the tensor and levator muscles from vascular damage. In the minority of patients where only a single vessel supplies the levator, a radical intrapalatal dissection may jeopardize its vascularity.     

Innervation of human soft palate muscles

Our objective was to determine the branching and distribution of the motor nerves supplying the human soft palate muscles. Six adult specimens of the soft palate in continuity with the pharynx, larynx, and tongue were processed with Sihler's stain, a technique that can render large specimens transparent while counterstaining their nerves. The cranial nerves were identified and dissection followed their branches as they divided into smaller divisions toward their terminations in individual muscles. The results showed that both the glossopharyngeal (IX) and vagus (X) nerves have three distinct branches, superior, middle, and inferior. Only the middle branches of each nerve contributed to the pharyngeal plexus to which the facial nerve also contributed. The pharyngeal plexus was divided into two parts, a superior innervating the palatal and neighboring muscles and an inferior innervating pharyngeal constrictors. The superior branches of the IX and X nerves contributed innervation to the palatoglossus, whereas their middle branches innervated the palatopharyngeus. The palatoglossus and palatopharyngeus muscles appeared to be composed of at least two neuromuscular compartments. The lesser palatine nerve not only supplied the palatal mucosa and palatine glandular tissue but also innervated the musculus uvulae, palatopharyngeus, and levator veli palatine. The latter muscle also received its innervation from the superior branch of X nerve. The findings would be useful for better understanding the neural control of the soft palate and for developing novel neuromodulation therapies to treat certain upper airway disorders such as obstructive sleep apnea.     

The lateral incisive canals of the adult hard palate - aberrant anatomy of a minor form of clefting?

Except the oral clefts and their associated dental development disturbances, no other discrete morphologies are reported in the literature as related to altered fusions of the fetal maxilla and premaxilla. We report here two cases related by the persistence in adult of an aberrant canal at the fusion site of the fetal premaxilla and maxilla. The first case presents an anastomosis of the superior anterior alveolar and greater palatine nerves, encountered during the dissection of a human adult male cadaver; that anastomosis, bilaterally present, projected on the aforementioned fusion site and traversed the hard palate to continue within the maxillary sinus wall. The second case evidenced on CT the unilateral presence of aberrant lateral incisive canals (LIC) at the level of the fetal premaxilla and maxilla fusion site; those canals, external (1.5 mm diameter) and internal (1.07 mm diameter), were corresponding as location to that one traversed by the aberrant anastomosis in the first case. Both LIC opened inferiorly but not superiorly, rather seeming to communicate with the bony canals within the nasal fossa floor at that level. We consider that such aberrant canals and nerves may represent very rare forms of clefting, previously undescribed; the possible anastomoses of the superior anterior alveolar and greater palatine nerves can be altered during a Le Fort I fracture and may be the morphology that can explain aberrant clinical nervous distributions at the level of the upper dentoalveolar arch and hard palate.     

Palatal analysis and osteology of the hard palate of the Kenyan African skulls

One hundred twenty-five dry skulls from Kenya that consisted of about 90% Bantu individuals were examined to obtain data on the gross anatomy of the hard palate. The palatine index showed that 43.2% of the total sample of skulls has narrow (leptostaphyline), 23.7% intermediate (mesostaphyline), and 33.1% wide (brachystaphyline) palates. The palatine height index showed that 40% skulls had low (chamestaphyline), 57% intermediate (orthostaphyline), and 3.0% deep (hypsistaphyline) palates. Mean palatal length, breadth, and height for the total sample was 4.92 cm, 4.02 cm, and 1.22 cm, respectively. The incisive foramen and canal was cone shaped in 80% where the diameter of the foramen was less than 0.4 cm, while it was cylindrical in 20% where the diameter was greater than 0.4 cm. Forty-nine per cent of the skulls had two-five lesser palatine foramina present. The greater palatine foramen was found to lie at the level of the third molar in 76%, intermediate between second and third molars in 13.6%, and opposite the second molar in 10.4%. The greater palatine foramen opened antero-medially in 74% and perpendicularly in 26% of the palates. Extensive longitudinal palatal grooves were found bilaterally in all the palates, 70% showed divisions of the grooves, 63.2% had crests along the border of the grooves, and 19.2% had bridges in the posterior part of the groove near the opening of the greater palatine foramen. The incidence of palatine torus was 4.8%. The incisive suture was present in 6.4% of the adult palates.     

Sagittal craniofacial growth evaluated on children dry skulls using V<Subscript>2</Subscript> and V<Subscript>3</Subscript> canal openings as references

The purpose of this study was to investigate the relationship between standard cephalometric landmarks and lines and those using ovale, rotundum, greater palatine and infra-orbital foramina as references. Thirty-four children dry skulls, 19 males and 15 females aged 0-6 years, were examined by computed tomography scanning. The classical cephalometric dimensions of skull base were measured from middle sagittal plane crossing over basion, nasion and sella turcica. Those of hard palate (maxilla and palatine bone) were measured from axial plane intersecting posterior nasal spine and anterior nasal spine. The dimensions between ovale and rotundum foramina, rotundum and infra-orbital foramina, greater palatine and infra-orbital foramina were determined by using constructed tomographic planes enclosing these different foramina. Biostatistical analysis using partial correlations showed that the linear variables with nerve canal openings as references are strongly related to length of both the skull base and of the hard palate. The results highlight the importance of the nerve canal openings of skull base and bone facial components in normal or pathologic craniofacial growth investigations.     

Topography of the greater palatine artery and the palatal vault for various types of periodontal plastic surgery

The purpose of the present study is to provide useful data that could be applied to various types of periodontal plastic surgery by detailing the topography of the greater palatine artery (GPA), looking in particular at its depth from the palatal masticatory mucosa (PMM) and conducting a morphometric analysis of the palatal vault. Forty‐three hemisectioned hard palates from embalmed Korean adult cadavers were used in this study. The morphometry of the palatal vault was analyzed, and then the specimens were decalcified and sectioned. Six parameters were measured using an image‐analysis system after performing a standard calibration. In one specimen, the PMM was separated from the hard palate and subjected to a partial Sihler's staining technique, allowing the branching pattern of the GPA to be observed in a new method. The distances between the GPA and the gingival margin, and between the GPA and the cementoenamel junction were greatest at the maxillary second premolar. The shortest vertical distance between the GPA and the PMM decreased gradually as it proceeded anteriorly. The GPA was located deeper in the high‐vault group than in the low‐vault group. The premolar region should be recommended as the optimal donor site for tissue grafting, and in particular the second premolar region. The maximum size and thickness of tissue that can be harvested from the region were 9.3 mm and 4.0 mm, respectively. Clin. Anat. 578–584, 2014. © 2013 Wiley Periodicals, Inc.     

Comparative Distribution and Arrangement of Herbst Corpuscles in the Oropharynx of the Ostrich (Struthio camelus) and Emu (Dromaius novaehollandiae)

Herbst corpuscles are widely distributed throughout the oropharynx of the ostrich and emu in contrast to the general situation in birds. Knowledge of the comparative distribution of Herbst corpuscles in the oropharynx of these two commercially important ratite species may assist in a better understanding of their feeding habits. Tissue sections representing all parts of the oropharynx of five ostrich and five emu heads collected after slaughter were prepared for light microscopy, the Herbst corpuscles counted, and the relative percentage of corpuscles calculated for defined anatomical regions. Herbst corpuscles were more widespread in the oropharynx of the emu (where they were additionally found in the tongue and laryngeal mound) than in the ostrich but were absent from the pharyngeal folds in both species. The results further indicated that Herbst corpuscles were strategically located to aid in the handling and transport of food. In this context, the high concentration of Herbst corpuscles in the prominent median palatine and ventral ridges in the ostrich denote these structures as sensory organs, namely the palatal and interramal organs. The presence of these sensory organs, coupled with the higher relative percentage of Herbst corpuscles located on the rostral oropharyngeal floor, indicate that the part of the oropharynx caudal to the mandibular and maxillary rostra forms an important sensory region in the ostrich. Additionally, species‐specific concentrations of Herbst corpuscles within the oropharynx were identified which appear to assist in the accurate positioning of the tongue and laryngeal mound for cleaning the choana (internal nares) after swallowing. Anat Rec, 297:1338–1348, 2014. © 2014 Wiley Periodicals, Inc.     

Mesenchymal fibroblast growth factor receptor signaling regulates palatal shelf elevation during secondary palate formation

Background : Palatal shelf elevation is an essential morphogenetic process during secondary palate closure and failure or delay of palatal shelf elevation is a common cause of cleft palate, one of the most common birth defects in humans. Here, we studied the role of mesenchymal fibroblast growth factor receptor (FGFR) signaling during palate development by conditional inactivation of Fgfrs using a mesenchyme‐specific Dermo1‐Cre driver. Results : We showed that Fgfr1 is expressed throughout the palatal mesenchyme and Fgfr2 is expressed in the medial aspect of the posterior palatal mesenchyme overlapping with Fgfr1. Mesenchyme‐specific disruption of Fgfr1 and Fgfr2 affected palatal shelf elevation and resulted in cleft palate. We further showed that both Fgfr1 and Fgfr2 are expressed in mesenchymal tissues of the mandibular process but display distinct expression patterns. Loss of mesenchymal FGFR signaling reduced mandibular ossification and lower jaw growth resulting in abnormal tongue insertion in the oral‐nasal cavity. Conclusions : We propose a model to explain how redundant Fgfr1 and Fgfr2 expression in the palatal and mandibular mesenchyme regulates shelf medial wall protrusion and growth of the mandible to coordinate the craniofacial tissue movements that are required for palatal shelf elevation. Developmental Dynamics 244:1427–1438, 2015. © 2015 Wiley Periodicals, Inc.     

Is the pterygopalatomaxillary suture (sutura sphenomaxillaris) a growing suture in the fetus?

The pterygopalatomaxillary suture is considered as having an important role in the posteroanterior growing of the maxilla. To determine whether this suture is a growing suture in the fetus, we performed a histological study of this suture in a fetus aged of 16 weeks of amenorrhea. Serial sections (5 μm) of the pterygopalatomaxillary suture area have been performed. Fibrous sutures are separating four pieces of ossification (maxilla, palatine bone, lateral and medial plates of the pterygoid process). A fibroblastic growing site has been observed on the dorsal aspect of the pterygopalatomaxillary suture, in contact to the anterior border of the lateral plate of the pterygoid process. The posteroanterior growing of maxilla is dependent on a growing suture located on the anterior border of the pterygoid process. The pterygoid process (via its lateral plate) makes the junction between the maxilla and both the cranial base and the condylar mandibular site of growth.