Characteristics of the topographic anatomical correlations of the chorda tympani, auriculotemporal nerve and anterior tympanic artery with the temporomandibular joint

The aim of the investigation was to reveal the possibility to draw into the pathological process known as the "Costen syndrome" the formations mentioned in the title. The investigation performed by means of the craniometry method on 150 mature person skulls, that are rather evenly distributed according to their sex, age and form, and simultaneous investigation of 70 heads of corpses of persons of both sex, gave the data denying the possibility of mechanical damage of the chorda tympani, when the mandibular head is shifted backward or medially. This phenomenon can be observed at a loss of teeth and lowered bite. When the mandibular head is shifted backward, it does not involve the chorda tympani, since the nerve gets out of the osseous canal more medially to the spine of the sphenoid bone. The medial shift of the mandibular head also cannot damage the chorda tympani, since the nerve is separated from the joint by a marked osseous protrusion. At the same time the data are obtained on variations in topography of the chorda tympani at various form of the intratemporal fossa. It has been stated that when a pathological process occurs around the temporomandibular joint, the auriculotemporal nerve and the anterior tympanic artery can be involved into this process. This can produce appearance of the "Costen syndrome" components.     

Sexual dimorphism of the canine roots in theMacaca fuscata

In situ radiographic analysis of the maxillary canines ofMacaca fuscata was conducted on 88 specimens in 44 individuals (23 dry skulls and 21 live animals) in order to examine the number of roots. The left canines were then extracted from ten female skulls for measurement, further radiographic examination, and visual morphological observation. The results showed a clear sexual dimorphism in root morphology: all male canines were clearly distinguished as single-rooted from the radiograph, whereas more than 40% of the female canines were double-rooted. Variation was also found among the single-rooted female canines, in that some of these teeth appeared to have a bifurcated canal. This sexual dimorphism in the number of maxillary canine roots and the individual variation found among the females in root and canal morphology are previously unreported for this species. No observations were attempted on mandibular canines, however, because of the incomplete nature of the sample.     

The human maxillary artery reinvestigated: I. Topographical relations in the infratemporal fossa.

The topographical relations of the human maxillary artery (IM) in the infratemporal fossa were studied in 102 individuals of both sexes. In the majority of the cases (55.4%), the artery was found in a lateral position to the lower head of the lateral pterygoid muscle (LPTER). In most of these specimens, the IM ran also lateral to the inferior alveolar, lingual and buccal nerves (type LA, 37.2%), whereas in 16.1% only the buccal nerve crossed the IM laterally (type LB). In 4.6%, the artery occupied a medial position to the LPTER. With respect to the branches of the mandibular nerve, an IM, passing deep to the LPTER, was lying either lateral to its main sensory branches (type MA, 1.9%) or coursing lateral to the inferior alveolar and lingual nerves, but medial to the buccal nerve (type MB, 23.8%). In 4.9%, the artery, running medial to the LPTER and the buccal nerve, was found to pierce the inferior alveolar nerve (type MC). In 7.4%, the IM was running medial to both the inferior alveolar and buccal nerves, but lateral to the lingual nerve (type MD), and in 3.9% the IM passed deep to all the branches of the mandibular nerve (type ME). Besides those common anatomical patterns, seven specimens showed different variations of the mandibular nerve. In about one third of the individuals, an asymmetric position of the IM to the LPTER (LM or ML) was present. None of the four cephalometric parameters and the two cephalic indices recorded in 55 individuals showed a significant correlation to the actual position of the IM (lateral or medial).     

Bone structure and the patterns of force transmission in the cat skull (Felis catus)

Projection microradiography was used to determine the density and orientation of the force transmitting structures, i.e., trabeculae and bone lying between approximately parallel vascular canals, within the bones of cat skulls. The organisation in the skulls was confirmed statistically for a total of ten cats. The results of the observations showed that within specific areas of the skull a high degree of structural orientation and an increased density of osseous structures was present. The distribution of these characters corresponded in contiguous bones such that a continuum of structural organisation was established between the alveolar region and the site of attachment of the temporalis and masseter muscles and the glenoid region. The patterns of force transmission during jaw closure were determined when a resistance was placed initially between the canines and then the carnassials. An analysis was first carried out on dry skulls using colophonium resin to determine the direction of the force distribution. The nature and the approximate magnitude of the forces were ascertained by replacing the resin with strain gauges. The basic similarities in the strain patterns recorded from the dry skulls and those from the ten anaesthetised cats in which strain gauges had been intra-vitally implanted, substantiated the recordings made on the dry skulls. Combination of the results from the three sets of experiments defined the patterns of force distribution in the cat skull during the closure of the mandible against a resistance. The results showed that: (1) the combined action of the temporalis and masseter muscles tended to reduce the overall strain in the skull bones, and that the deformations produced by the action of the masseter were greater than that exerted by the temporalis muscles; (2) during biting, whether the resistance was placed between the canines or carnassials, compressive forces predominated in the facial bones; (3) small movements observed between facial bones indicated the presence of a flexible component within the skull, thus allowing large forces to be exerted during biting without overstressing the facial bones; (4) the glenoid fossa is part of a force bearing joint; (5) forces generated during biting were resisted within the skull by forces of an opposite nature generated within the system, the incompressible nature of bone and by the effect of the soft tissues; (6) the nature and the magnitude of the strain altered when a resistance was placed at the canines and then at the carnassials; however, the pattern of force distribution within the skull remained the same; (7) there was a direct correspondence between the detailed structural organisation of the bones and the patterns of force distribution. This conclusion would appear to apply in general to mammalian skulls. The study also emphasises the importance, neglected hitherto, of carrying out a variety of experiments to determine the patterns of force distribution in bones. The Trajectorial Theory of bone organisation is discussed and, on the basis of the results obtained, a modified theory is proposed. This states that: the structural continuum is common to the compact and cancellous bone and comprises bony bars which are aligned in the optimum direction for the transmission of force to a region in the bone or bones where it is effectively resisted.     

Jugular foramen and mylohyoid bridging in an Asian Indian population

The incidence of jugular foramen and mylohyoid groove bridging was studied in a population of East Asian Indian skulls (125 males and 109 females). The criteria of Dodo (J. Anat. 144:153-165, 1986) was used in the identification of a jugular bridge. There was an overall incidence of 8.1% in jugular foramen bridging, with males showing a higher rate, though the difference did not reach statistical significance. The right side showed a statistically significant greater occurrence than the left, and the trait tended to be associated between sides. The overall incidence of mylohyoid bridging was found to be 2.6%, with no difference observed between the sexes. This frequency is less than the values reported for other Asian Indian studies. Studies concerned with the incidences of nonmetric traits such as bony bridging may be useful in population studies especially when utilized in combination, thereby enhancing the value of each trait as an anthropological tool.     

Brief communication: The size of the human frontal sinuses in adults presenting complete persistence of the metopic suture

The notion of absence of the frontal sinuses in human individuals presenting a persistence of the metopic suture is considered as classical in many treatises of reference; however, precise studies are very rare and even controversial. The purpose of this study was thus to provide original data to confirm or refute this classical affirmation with the perspective of some original insights into biological significance of the frontal sinuses and the factors influencing their exceptional polymorphism. The material consisted of 143 dry skulls of adult individuals (European Homo sapiens), distributed in two groups: 80 skulls presenting a complete frontal closure with total disappearance of the metopic suture, and 63 skulls presenting a complete persistence of the metopic suture. Each skull was radiographed in oblique projection using the occipitomental view. A simple morphological quantification of the sinus size was defined with four categories: (1) aplasia, (2) hypoplasia, (3) medium size, (4) hyperplasia. Statistically significant difference in frontal sinusal size was found between both groups of skulls. Absent and small sinuses were considerably more frequent in skulls with persistence of the metopic suture (57.9 vs. 11.9%): small frontal sinuses (hypoplasia) were much more frequent (50.8 vs. 9.4%), although the frequency of absence of frontal sinuses (aplasia) was only slightly higher (7.1 vs. 2.5%). Am J Phys Anthropol 154:621–627, 2014. © 2014 Wiley Periodicals, Inc.     

Healing of "wire tunnels" in tibial diaphysis: data of local X-ray study and densitometry

Fifteen pelvic extremities from adult dogs were used to perform 60 cross tunnelization of tibial diaphysis with a wire having a pointed groove, 1.8-mm in diameter, at 1,500 rpm. Thirty five leg X-ray films in the lateral projection, which show changes on days 30, 60, 90, 120, 520 after the experiment, were studied. Bony diaphysis tunnelization was found to give rise to a regeneration focus wherein an area of tissue element degradation and an area of introduction of bony fragments into soft tissues were detectable. Changes in the regeneration focus were determined by a response to osseous fragments, which involved the formation of an bony regenerate during a month and to the resorption of the bony matter of an osseous regenerate and osseous fragments in future. Healing of diaphysis defects began with the resorption of a damaged cortical layer. Osteogenesis prevailed at month 2 and ensured healing of cortical layer defects following 4-6 months.     

Hawaiian craniofacial morphometrics: Average Mokapuan skull,artificial cranial deformation,and the “rocker” mandible

Craniofacial morphology and cultural cranial deformation were analyzed by the computer morphometric system in 79 adult Hawaiian skulls from Mokapu, Oahu. The average Hawaiian male was large, but similar in shape to the female. Both were larger than the present Caucasian, showed a greater dental protrusion, and possessed a larger ANB angle, flatter cranial base, and larger facial heights. Correlations in Hawaiian craniofacial structure were found between an increasing mandibular plane angle and (1) shorter posterior facial height, (2) larger gonial angle, (3) larger cranial base angle, and (4) smaller SNA and SNB angles. Of the 79 skulls studied, 8. 9% were found to have severe head molding or intentional cranial deformation. Significant statistical differences between the molded group and the nonmolded group are, in decreasing significance: (1) larger upper face height, (2) smaller glabella to occiput distance, and (3) increased lower face height with deformation. The morphometric differences were readily seen by graphic comparison between groups. It is postulated that external forces to the neurocranium result in redirection of the growth vectors in the neurocranial functional matrix, including the cranial base, and secondarily, to the orofacial functional matrix. There is a possibility that the cranial deformation is a retention of the normal birth molding changes. The Polynesian “rocker jaw” was found in 81% to 95% of this populace. This mandibular form occurs only with attainment of adult stature and craniofacial form. This data agrees with the hypothesis that mandibular form is modified by the physical forces present and their direction in the orofacial functional matrix.     

Quantitative studies on the regeneration of myelinated nerve fibers. I. Variations in the number and the size of myelinated fibers in the nerves of normal rats]

The number and size of myelinated nerve fibers have been determined at standard levels in the nerve to medial head of right and left gastrocnemius muscles of 24 normal rats (11 males and 13 females). The mean values of all results were comparable on right and left sides. Thus, 271 +/- 5 myelinated nerve fibers were found in the right nerve and 272 +/- 4 in the left; their mean diameter were respectively 8.1 +/- 0.1 and 8.0 +/- 0.1 micron. There were 60.1% of large nerve fibers on the right side and 59,9% on the left, their mean diameters being 10.5 and 10.6 micron. Some variations occured in all these values, depending of the weight and sex of the animals. Nevertheless, the differences between both sides of a same rat were negligible and the histograms of both nerves could be superposed. Accordingly, in the operated animals, the contralateral nerve may be used as control.     

香港地区现代人头骨的研究：性别和地区类型的判别分析

本文报告了香港地区现代中国人头骨测量性状的性别差异情况和香港与太原的男性头骨的差异情况。在此基础上,使用判别分析的方法建立了各自的判别函数,正判率分别达到93.1％和85.3％。它们分别适用于华南头骨的性别鉴定和华南与华北男性头骨的区分。     

Mental foramen and mental nerve: changes with age

In a study of 525 dry mandibles and dissections in 50 cadavers, the mental foramen (MF) was found: single in 94.67% of the cases and multiple in 5.33%. Its shape was round in 34.48% with an average diameter of 1.68 mm and oval in 65.52% with an average long diameter of 2.37 mm. In 43.66% the MF was located in front of the apex of the root of the second premolar. In children before tooth eruption, the MF is somewhat closer to the alveolar margin; during the eruption period, the MF descends to half way between the margins, and in adults with the teeth preserved, the MF is somewhat closer to the inferior border. With loss of teeth and bone resorption the MF moves upwards closer to the alveolar border. In extreme cases of resorption the MF and the adjacent part of the mandibular canal are open at the alveolar margin. In the dissections the findings were similar. The mental nerve emerged from the MF closer to or at the alveolar border, according to the degree of resorption. In extreme degrees of resorption, the mental nerve and the final part of the inferior alveolar nerve were found directly under the gums. In these cases, the vestibular grooves became very shallow, and the mucosa passed directly from the cheeks over the alveolar ridge. Practical implications of the changes of the MF and mental nerve are discussed.     

太原地区现代人头骨的研究

本文报告了太原地区男、女组现代人头骨测量性状的基本统计量和非测量性状的出现情况,记述和讨论了它们的两侧差异和性别差异情况,建立了以多个项目测量值鉴定华北人头骨性别的判别函数。     

Maxillary changes and occlusal traits in crania with artificial fronto-occipital deformation

Artificial fronto-occipital deformation of the cranial vault was typical of pre-Columbian cultures in the central Andean coastal regions. We have studied the influence of this deformation on maxillary and mandibular morphology. Measurements were performed on 86 adult Ancon skulls with anteroposterior deformation. Undeformed skulls from the area of Makatampu (n = 52) were used as the control group. To explore the influence of the deformity on occlusion, the skulls were categorized using the Angle classification and the alignment of the interincisor midline. In the group of deformed skulls, there was an increase in lateral growth of the vault and of the base of the skull (P < 0.001), giving rise to a greater interpterygoid width of the maxilla (P < 0.001), and an increase in the transverse diameter of the palatal vault. The mandible presented an increase in the length of the rami (P < 0.001) and in the intercondylar width, with no alteration of mandibular length. The deformed skulls had normal (class I) occlusion, with no displacement of the midline. The difference in the asymmetry index between the two groups was not statistically significant. Artificial fronto-occipital deformation of the cranial vault provoked compensatory lateral expansion of the base that was correlated with the transverse development of the maxilla and mandible. Occlusion and sagittal intermaxillary position were not affected by the cranial deformity. These results provide evidence of the integration between the neurocranium and the viscerocranium in craniofacial development, and support the hypothesis of a compensatory effect of function.     

New methods of dissecting the masticator space of the rhesus macaque (<Emphasis Type="Italic">Macaca mulatta</Emphasis>)

The aim of our project was to develop a method to examine the deep masticator space of the rhesus macaque (Macaca mulatta) in order to investigate the following particulars of the mandibular nerve: (1) its manner of entry into the masticator space, (2) its branching within spaces/canals in the spheno-temporal bony complex, and (3) the location of its principal divisions with reference to the lateral pterygoid plate and muscle heads. In order to access these structures it was necessary to develop novel lateral and medial approaches. These and the instruments used are described. The proximal branching of the mandibular nerve is described and contrasted with that of the human. The implications of nerve branching in humans with reference to (1) evolution, (2) electromyography and (3) anesthetic control are discussed.     

国人颅骨颈动脉管外口及其周围某些结构的形态观察与测量

本文对国人颅骨133例,266个颈动脉管外口形状大小进行了观察与测量。结果表明:颈动脉管外口形状不一。可区分为圆形、卵圆形和南瓜子仁形三种,其中以圆形者为数最多。颈动脉管外口长宽径和距颈静脉窝及锥体尖端之间距离两侧不等,并具有地区性差异。鼓小管下口在个别颅骨缺如。颈静脉窝之大小深浅不一,其中以右侧较大而深者为最多。     

Thin-plate spline analysis of allometry and sexual dimorphism in the human craniofacial complex

The relationship between allometry and sexual dimorphism in the human craniofacial complex was analyzed using geometric morphometric methods. Thin-plate splines (TPS) analysis has been applied to investigate the lateral profile of complete adult skulls of known sex. Twenty-nine three-dimensional (3D) craniofacial and mandibular landmark coordinates were recorded from a sample of 52 adult females and 52 adult males of known age and sex. No difference in the influence of size on shape was detected between sexes. Both size and sex had significant influences on shape. As expected, the influence of centroid size on shape (allometry) revealed a shift in the proportions of the neurocranium and the viscerocranium, with a marked allometric variation of the lower face. Adjusted for centroid size, males presented a relatively larger size of the nasopharyngeal space than females. A mean-male TPS transformation revealed a larger piriform aperture, achieved by an increase of the angulation of the nasal bones and a downward rotation of the anterior nasal floor. Male pharynx expansion was also reflected by larger choanae and a more posteriorly inclined basilar part of the occipital clivus. Male muscle attachment sites appeared more pronounced. In contrast, the mean-female TPS transformation was characterized by a relatively small nasal aperture. The occipital clivus inclined anteriorly, and muscle insertion areas became smoothed. Besides these variations, both maxillary and mandibular alveolar regions became prognathic. The sex-specific TPS deformation patterns are hypothesized to be associated with sexual differences in body composition and energetic requirements.     

Aberrant growth of maxillary canine teeth in male babirusa (genus Babyrousa)

A worldwide survey of babirusa skulls curated in museum and private collections located 431 that were from adult males and had retained at least one maxillary canine tooth. Eighty-three of these skulls were identified as exhibiting aberrant maxillary canine tooth growth. Twenty-four of the skulls represented babirusa from Buru and the Sula Islands, and forty-five skulls represented babirusa from Sulawesi and the Togian Islands. The remaining series of fourteen babirusa skulls originally came from zoo animals. Fifteen skulls showed anomalous alveolar and tooth rotation in a median plane. Twenty-nine skulls had maxillary canine teeth that did not grow symmetrically towards the median plane of the cranium. Fourteen skulls showed evidence that the tips of one or both maxillary canine teeth had eroded the nasal bones. Twenty-one skulls had maxillary canine teeth that had eroded the frontal bones. The teeth of two skulls had eroded a parietal bone. One skull had two maxillary canines arising from an adjacent pair of alveoli on the left side of the cranium. Three skulls exhibited alveoli with no formed maxillary canine teeth in them. Analysis suggested that approximately 12% of the adult male babirusa in the wild experience erosion of the cranial bony tissues as a result of maxillary canine tooth growth. There was no skeletal evidence that maxillary canine teeth penetrate the eye.     

国人分裂颧骨的观察

观察了200个成人颅骨,不完全二分颧骨的出现率最高,完全二分颧骨次之,三分颧骨最少。不完全二分颧骨各缝的出现率不同,其中以后水平缝多见,前水平缝次之,全水平缝更少。本文还对该骨出现的成因进行了探讨。