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The vestibule belongs to the oral cavity – it is bounded internally by the teeth and externally by the soft tissues of the lips and cheeks. The vestibule provides access to the teeth and their supporting structures from the labial and buccal aspects and thus is important in clinical dentistry for carrying out diagnostic, operative, and surgical interventions. This chapter illustrates the anatomical structures of the vestibule and cheeks including their function and clinical significance.

The lingual and mylohyoid nerves are presented together due to their corresponding morphological features. These include a common origin from the posterior trunk of the mandibular nerve (third division of CN V), similar trajectories through the infratemporal fossa to reach the posterior portion of the floor of the mouth, and multiple neural connections throughout their course. An understanding of the course and morphological configuration of the lingual nerve is particularly critical due to its common involvement, either directly or indirectly during mandibular block anesthesia, either directly or indirectly.

The floor of the mouth, also called “diaphragma oris,” includes the soft tissues between the medial aspect of the mandibular body and the hyoid bone. As such, it represents the inferior border of the oral cavity. Four of the six large salivary glands are associated with the floor of the mouth, i.e., the sublingual and submandibular glands. The main muscles contributing to the floor of the mouth include the mylohyoid and the geniohyoid muscles. The major arterial supply to the floor of the mouth is provided by the sublingual and submental arteries.

The mandibular incisive canal is rarely addressed in textbooks but merits attention since it carries neurovascular structures to the mandibular canines and incisors. The mandibular incisive canal originates from the mandibular canal at the level of the mental foramen, and in fact, it is the continuation of the mandibular canal into the interforaminal region. Surgical damage to the mandibular incisive canal may result in neurosensory disturbances of the mandibular anterior teeth but may even lead to skin paresthesia due to a retrograde “stretching” of the mental nerve.

The roof of the oral cavity is formed by the hard and soft palate. While the main component of the hard palate is bone, the soft palate mainly consists of the muscles that play an important role in controlling the oropharyngeal isthmus. The largest blood vessel in the palate is the greater palatine artery that exits the greater palatine foramen and then courses anteriorly through the palatine sulcus. This artery must be taken into consideration when performing incisions, harvesting connective tissue grafts, or making osteotomies in the (posterior) palate.

Intracranial lipomas are rare, but 45% of them occur along the midline cisterns between the hemispheres and are often associated with corpus callosum hypoplasia and craniofacial defects. They are difficult to detect, as they are generally asymptomatic and visible by MRI or by postmortem examination. The exact cause of these interhemispheric lipomas is not known, but they arise from a developmental defect resulting in the maldifferentiation of mesenchymal cells into mesodermal derivatives that are not normally present. We have identified a new mouse mutant called tuft, exhibiting a forebrain, intracranial lipoma with midline craniofacial defects resembling frontonasal dysplasia (FND) that arose spontaneously in our wild-type 3H1 colony. The tuft trait appears to be transmitted in recessive fashion, but approximately 80% less frequent than the expected Mendelian 25%, due to either incomplete penetrance or prenatal lethality. MRI and histological analysis revealed that the intracranial lipoma occurred between the hemispheres and often protruded through the sagittal suture. We also observed a lesion at the lamina terminalis that may indicate improper closure of the anterior neuropore. We have mapped the tuft trait to within an 18 cM region on mouse chromosome 10 by microsatellite linkage analysis and identified several candidate genes involved with craniofacial development and cellular differentiation of adipose tissue. tuft is the only known mouse model for midline craniofacial defects with an intracranial lipoma. Identifying the gene(s) and mutation(s) causing this early developmental defect will help us understand the pathogenesis of FND and related craniofacial disorders.

Primary intraosseous squamous cell carcinoma is a rare malignant central jaw tumor derived from odontogenic epithelial remnants. Predominantly, it affects mandible, although both jaw bones may be involved. This report describes a 60-year-old man who was initially misdiagnosed with a periapical infection related to the right lower wisdom tooth. After four months, the patient presented to a private dental clinic with a massive swelling at the right side of the mandible. Panoramic radiographs and advanced imaging revealed a lesion with complete erosion of the right ramus, which extended to the orbital floor. A biopsy from the mandibular angle revealed large pleomorphic atypical squamous cells, which is the primary microscopic feature of a poorly differentiated squamous cell carcinoma.

The minipig provides an excellent experimental model for tooth morphogenesis because its diphyodont and heterodont dentition resemble that of humans. However, little information is available on the processes of tooth development in the pig. The purpose of this study was to classify the early stages of odontogenesis in minipigs from the initiation of deciduous dentition to the late bell stage when the successional dental lamina begins to develop. To analyze the initiation of teeth anlagens and the structural changes of dental lamina, a three-dimensional (3D) analysis was performed. At the earliest stage, 3D reconstruction revealed a continuous dental lamina along the length of the jaw. Later, the dental lamina exhibited remarkable differences in depth, and the interdental lamina was shorter. The dental lamina grew into the mesenchyme in the lingual direction, and its inclined growth was underlined by asymmetrical cell proliferation. After the primary tooth germ reached the late bell stage, the dental lamina began to disintegrate and fragmentize. Some cells disappeared during the process of lamina degradation, while others remained in small islands known as epithelial pearls. The minipig can therefore, inter alia, be used as a model organism to study the fate of epithelial pearls from their initiation to their contribution to pathological structures, primarily because of the clinical significance of these epithelial rests.

Purpose: Traction-induced injury, related to muscles of the superficial and deep posterior compartments, has been implicated as the cause of medial tibial stress syndrome (MTSS) with symptoms commonly occurring in the distal third of the posteromedial tibia. Standard anatomic texts do not identify this region as an attachment site for these structures. Research into the anatomical arrangement of these structures has been inconclusive. The deep crural fascia (DCF) has been implicated as a cause of traction-induced injury in MTSS but not fully researched. The purpose of this study was to define the tibial origins of the DCF and the muscles of the superficial and deep posterior compartments relative to MTSS-related pain commonly reported along the distal one half to one third of the diaphysis of the medial tibial border and to identify the prevalence of a soleal aponeurosis. Methods: The tibial attachments of the DCF, the soleus, the flexor digitorum longus, and the tibialis posterior were quantified relative to the medial malleolus in sixteen cadaver specimens. Results: Mean distal attachments to the medial tibial border were superior to the distal third of the tibia for the muscles of the posterior compartments, suggesting that the role of the soleus, the tibialis posterior, and the flexor digitorum longus in producing pain typically associated with MTSS may be limited. The DCF of all but three specimens attached along the entire length of the medial tibia investing the medial malleolus. Conclusion: Traction-induced injury theories involving the muscles of the superficial and deep posterior compartments are not supported by anatomical evidence in the present study. The tibial attachments of the DCF in this study support theories implicating DCF involvement in creating traction-induced injury.

The Br/+ mutant mouse displays decreased embryological expression of the homeobox transcription factor Six2, resulting in hertitable renal hypoplasia. The purpose of this study was to characterize the renal physiological consequences of embryonic haploinsuffiency of Six2 by analyzing renal morphology and function in the adult Br heterozygous mutant. Adult Br/+ kidneys weighed 50% less than those from wild-type mice and displayed glomerulopathy. Stereological analysis of renal glomeruli showed that Br/+ kidneys had an average of 88% fewer glomeruli than +/+ kidneys, whereas individual glomeruli in Br/+ mice maintained an average volume increase of 180% compared with normal nephrons. Immunostaining revealed increased levels of endothelin-1 (ET-1), endothelin receptors A (ETA) and B (ETB), and Na-K-ATPase were present in the dilated renal tubules of mutant mice. Physiological features of chronic renal failure (CRF) including elevated mean arterial pressure, increased plasma creatinine, and dilute urine excretion were measured in Br/+ mutant mice. Electron microscopy of the Br/+ glomeruli revealed pathological alterations such as hypercellularity, extracellular matrix accumulation, and a thick irregular glomerular basement membrane. These results indicate that adult Br/+ mice suffer from CRF associated with reduced nephron number and renal hypoplasia, as well as glomerulopathy. Defects are associated with embryological deficiencies of Six2, suggesting that proper levels of this protein during nephrogenesis are critical for normal glomerular development and adult renal function.

A radiation-induced mouse mutant, Brachyrrhine (Br), exhibits frontonasal dysplasia and renal hypoplasia, two malformations associated with deficiencies in mesenchymal condensation. The purpose of this study was to resolve the Br locus, evaluate possible candidate genes, and identify developmental defects in the mutant chondrocranium. Linkage analysis mapped the Br mutation to a critical region distal to D17Mit76, which contains only one gene, the transcription factor Six2. Sequence analysis of the Six2 gene, including 1.5 kb of the promoter, failed to reveal the Br mutation. However, homozygous Br/Br embryos showed almost complete absence of Six2 mRNA and protein in craniofacial and renal tissues while heterozygous Br/+ embryos displayed intermediate Six2 levels. Mutant embryos displayed malformations of neural crest-derived structures of the anterior cranium where Six2 is normally expressed. These data suggest a mutation in a novel cis-acting regulatory region inhibits Six2 expression and is associated with frontonasal dysplasia and renal hypoplasia.

Introduction This article presents the results of a demonstration project that was designed with the goal to determine the feasibility and acceptability of medical students in using distance technology and virtual reality (VR) simulation within a problem-based learning (PBL). Methods This pilot project involved students from the Universities of New Mexico and Hawaii and compared (1) control groups consisting of medical students in a tutor-guided PBL session using a text-based case, (2) distance groups using the same text-based case but interacting over distance from multiple sites, (3) groups using a VR simulation scenario integrated into the case without interaction over distance, and (4) combination groups interacting over distance from multiple sites with integration of a VR simulation scenario. Results The study results suggest that it is possible to successfully conduct a PBL tutorial with medical students from two institutions with the integration VR and distributed distance interaction in combination or independently. The addition of these modalities did not interfere with learning dynamics when compared with traditional tutorial sessions. Conclusions These findings suggest the feasibility and acceptability by students in the use of VR simulation integrated into a PBL learning session, as well as multipoint distance technologies that allowed interaction between students and tutors in different locations. The authors believe that these modalities can be applied where students and tutors from different institutions are in separate locations and can be used to support interactive experiential learning in a distributed network or on site and suggest areas for additional research.

Knowledge of anatomical variations is critical to avoid clinical complications and it enables an understanding of morphogenetic mechanisms. Depictions are comprised of photographs or illustrations often limiting appreciation of three-dimensional (3D) spatial relationships. The purpose of this study is to describe an approach for presenting anatomical variations utilizing video clips emphasizing 3D anatomical relationships delivered on personal electronic devices. An aberrant right subclavian artery (ARSA) was an incidental finding in a routine dissection of an 89-year-old man cadaver during a medical student instructional laboratory. The specimen was photographed and physical measurements were recorded. Three-dimensional models were lofted and rendered with Maya software and converted as Quicktime animations. Photographs of the first frame of the animations were recorded and registered with Aurasma Mobile App software (www.aurasma.com). Resulting animations were viewed on mobile devices. The ARSA model can be manipulated on the mobile device enabling the student to view and appreciate spatial relationships. Model elements can be de-constructed to provide even greater spatial resolution of anatomical relationships. Animations provide a useful approach for visualizing anatomical variations. Future work will be directed at creating a library of variants and underlying mechanism of formation for presentation through the Aurasma application.

Computerized reconstruction of anatomical structures is becoming very useful for developing anatomical teaching modules and animations. Although databases exist consisting of serial sections derived from frozen cadaver material, plastination represents an alternate method for developing anatomical data useful for computerized reconstruction. Plastination is used as an excellent tool for studying different anatomical and clinical questions. The sheet plastination technique is unique because it offers the possibility to produce transparent slices series, which can easily be processed morphometrically. The purpose of this study was to describe a method for developing a computerized model of the human ankle using plastinated slices. This method could be applied to reconstruct any desired region of the human body. A human ankle was obtained, plastinated, sectioned, and subjected to 3D computerized reconstruction using WinSURF modeling system (SURFdriver Software). Qualitative observations revealed that the morphological features of the model were consistent with those displayed by typical cadaveric specimens. Morphometric analysis indicated that the model did not significantly differ from a sample of cadaveric specimens. These data support the use of plastinates for generating tissues sections useful for 3D computerized modeling. Clin. Anat. 20:196–200, 2007. © 2006 Wiley-Liss, Inc.

The anterior superior alveolar nerve (ASAN) is a branch of the infraorbital nerve. Only few studies have morphometrically evaluated the course of the ASAN. Midfacial segments of ten hemisectioned fresh adult cadaver heads were dissected to uncover the anterior wall of the maxilla. Specimens were subsequently decalcified and the bone overlying the ASAN was removed under a microscope to expose the ASAN. Its branching pattern from the infraorbital nerve was recorded, and the course of the ASAN within the anterior wall of the maxillary sinus was morphometrically assessed measuring distances to predefined landmarks using a digital caliper. A distinct ASAN was observed in all specimens. It arose lateral (six cases) or inferior (four cases) from the infraorbital nerve. The point of origin was located at a mean distance of 12.2 ± 5.79 mm posterior to the infraorbital foramen. The ASAN was located on average 2.8 ± 5.13 mm lateral to the infraorbital foramen. After coursing medially, the ASAN ran inferior to the foramen at a mean distance of 5.5 ± 3.07 mm. When approaching the nasal aperture, the loop of the ASAN was on average 13.6 ± 3.07 mm above the nasal floor. The horizontal mean distance from the ASAN to the nasal aperture was 4.3 ± 2.74 mm halfway down from the loop, and 3.3 ± 2.60 mm at the floor of the nose, respectively. In conclusion, the present study evaluated the course of the ASAN relative to the infraorbital foramen and nasal aperture. This information is helpful to avoid damage to this anatomical structure during interventions in the infraobrital region of the maxilla. Further, knowledge of the course of the ASAN and of its bony correlate (canalis sinuosus) may be valuable in interpreting anesthetic or radiologic findings in the anterior maxilla.

Genetic variations affecting neural tube closure along the head result in malformations of the face and brain. Neural tube defects (NTDs) are among the most common birth defects in humans. We previously reported a mouse mutant called tuft that arose spontaneously in our wild-type 3H1 colony. Adult tuft mice present midline craniofacial malformations with or without an anterior cephalocele. In addition, affected embryos presented neural tube closure defects resulting in insufficient closure of the anterior neuropore or exencephaly. Here, through whole-genome sequencing, we identified a nonsense mutation in the Tet1 gene, which encodes a methylcytosine dioxygenase (TET1), co-segregating with the tuft phenotype. This mutation resulted in premature termination that disrupts the catalytic domain that is involved in the demethylation of cytosine. We detected a significant loss of TET enzyme activity in the heads of tuft embryos that were homozygous for the mutation and had NTDs. RNA-Seq transcriptome analysis indicated that multiple gene pathways associated with neural tube closure were dysregulated in tuft embryo heads. Among them, the expressions of Cecr2, Epha7 and Grhl2 were significantly reduced in some embryos presenting neural tube closure defects, whereas one or more components of the non-canonical WNT signaling pathway mediating planar cell polarity and convergent extension were affected in others. We further show that the recombinant mutant TET1 protein was capable of entering the nucleus and affected the expression of endogenous Grhl2 in IMCD-3 (inner medullary collecting duct) cells. These results indicate that TET1 is an epigenetic determinant for regulating genes that are crucial to closure of the anterior neural tube and its mutation has implications to craniofacial development, as presented by the tuft mouse., Summary: We propose an epigenetic mechanism establishing the regulation of genes that are crucial for neural tube closure. This mechanism could be a novel target for resolving such birth defects and associated disorders.

The interorbital septum is the portion of the anterior cranial base directly contiguous with the eyes. It is considered to be a primitive trait that has evolved independently in various primate groups as a result of ocular and olfactory convergence with concomitant encephalization. This process is hypothesized to have reduced the size of the lateral nasal capsule exposing the anterior cranial base to the ocular apparatus and thus creating an interorbital septum. The purpose of this study was to determine whether differential growth trajectories occur among the chondrocranial elements corresponding to this hypothesis. Macaca mulatta embryos from the Zingeser Collection were selected for this analysis since this primate shows a well-developed interorbital septum throughout ontogeny. Embryos between 40 and 90 days of gestation were selected from the collection and coronal sections including the eye, anterior cranial base and lateral nasal capsule were subjected to video microscopy and computerized reconstruction using SURFdriver Software. Tissue volumes were computed for these tissues while chondrocytic growth attributes were measured utilizing stereological techniques. Results showed a strong correlation between the volume of the lateral nasal capsule and anterior cranial base and these two structures showed a consistent correlation with an increasing eye volume. Chondrocytic volume density and average diameter were larger in the lateral nasal capsule while shape, numerical density and average volume did not differ between the two tissues. These data suggest if differential growth does account for a reduction of the nasal capsule compared to the central cranial base stem, it does not appear to result from differential tissue size change. However, certain cellular growth activities leading to premature chondrocytic hypertrophy may be involved.

The adult Brachyrrhine (3H1 Br/+) mouse displays severe midfacial retrognathia, with a "pugnose" external appearance, but information concerning craniofacial morphology of the homozygote (3H1 Br/Br) mutant is lacking. This study characterized craniofacial phenotype and genotypic features of the homozygous condition. Segregation analysis was performed by phenotypic scoring of offspring from 3H1 Br/+ reciprocal matings. Whole-mount staining was undertaken to determine the presence or absence of cranial base structures in newborn and adult mice, while features of cranial base chondrification were examined using light microscopy and type II collagen immunohistochemistry. Karyotype analysis was performed to determine whether gross chromosomal aberrations were present. Finally, microsatellite mapping analysis was undertaken to provide further resolution of the Br locus. Results showed that Br was inherited as an autosomal semidominant feature. 3H1 Br/Br mice consistently lacked a presphenoid (with its lateral projections, including a preoptic root, postoptic root, and lesser wing). Karyotyping did not reveal major gross aberrations; however, microsatellite analysis localized Br to distal mouse chromosome 17 in the vicinity of D17Mit155. These results indicated that 3H1 Br/Br mice show characteristic features of frontonasal dysplasia, including median facial clefting and bifid cranium, as well sphenoidal malformations. Furthermore, this mutant should serve as a useful model for examining mechanisms of frontonasal dysplasia.

Distance education delivery has increased dramatically in recent years as a result of the rapid advancement of communication technology. The National Computational Science Alliance's Access Grid represents a significant advancement in communication technology with potential for distance medical education. The purpose of this study is to provide an overview of the TOUCH project (Telehealth Outreach for Unified Community Health; http://hsc.unm.edu/touch) with special emphasis on the process of problem-based learning case development for distribution over the Access Grid. The objective of the TOUCH project is to use emerging Internet-based technology to overcome geographic barriers for delivery of tutorial sessions to medical students pursuing rotations at remote sites. The TOUCH project also is aimed at developing a patient simulation engine and an immersive virtual reality environment to achieve a realistic health care scenario enhancing the learning experience. A traumatic head injury case is developed and distributed over the Access Grid as a demonstration of the TOUCH system. Project TOUCH serves as an example of a computer-based learning system for developing and implementing problem-based learning cases within the medical curriculum, but this system should be easily applied to other educational environments and disciplines involving functional and clinical anatomy. Future phases will explore PC versions of the TOUCH cases for increased distribution.

Computerized animation is becoming an increasingly popular method to provide dynamic presentation of anatomical concepts. However, most animations use artistic renderings as the base illustrations that are subsequently altered to depict movement. In most cases, the artistic rendering is a schematic that lacks realism. Plastinated sections provide a useful alternative to artistic renderings to serve as a base image for animation. The purpose of this study is to describe a method for developing animations by using plastinated sections. This application is used in Project TOUCH as a supplemental learning tool for a problem-based learning case distributed over the National Computational Science Alliance's Access Grid. The case involves traumatic head injury that results in an epidural hematoma with transtentorial uncal herniation. In addition, a subdural hematoma is animated permitting the student to contrast the two processes for a better understanding of dural hematomas, in general. The method outlined uses P40 plastinated coronal brain sections that are digitized and to which contiguous anatomical structures are rendered. The base illustration is rendered, interpolated, and viewed while audio narration describes the event. This method demonstrates how realistic anatomical animations can be generated quickly and inexpensively for medical education purposes by using plastinated brain sections.

Project TOUCH (Telehealth Outreach for Unified Community Health; http://hsc.unm.edu/touch) investigates the feasibility of using advanced technologies to enhance education in an innovative problem-based learning format currently being used in medical school curricula, applying specific clinical case models, and deploying to remote sites/workstations. The University of New Mexico's School of Medicine and the John A. Burns School of Medicine at the University of Hawai'i face similar health care challenges in providing and delivering services and training to remote and rural areas. Recognizing that health care needs are local and require local solutions, both states are committed to improving health care delivery to their unique populations by sharing information and experiences through emerging telehealth technologies by using high-performance computing and communications resources. The purpose of this study is to describe the deployment of a problem-based learning case distributed over the National Computational Science Alliance's Access Grid. Emphasis is placed on the underlying technical components of the TOUCH project, including the virtual reality development tool Flatland, the artificial intelligence-based simulation engine, the Access Grid, high-performance computing platforms, and the software that connects them all. In addition, educational and technical challenges for Project TOUCH are identified.

The present article reviews the different types of ophthalmologic complications following administration of intraoral local anesthesia. Since the first report by Brain in 1936, case reports about that topic have been published regularly in the literature. However, clinical studies evaluating the incidence of ophthalmologic complications after intraoral local anesthesia are rarely available. Previous data point to a frequency ranging from 0.03% to 0.13%. The most frequently described ophthalmologic complications include diplopia (double vision), ptosis (drooping of upper eyelid), and mydriasis (dilatation of pupil). Disorders that rather affect periorbital structures than the eye directly include facial paralysis and periorbital blanching (angiospasm). Diverse pathophysiologic mechanisms and causes have been reported in the literature, with the inadvertent intravascular administration of the local anesthetic considered the primary reason. The agent as well as the vasopressor is transported retrogradely via arteries or veins to the orbit or to periorbital structures (such as the cavernous sinus) with subsequent anesthesia of nerves and paralysis of muscles distant from the oral cavity. In general the ophthalmologic complications begin shortly after administration of the local anesthesia, and disappear once the local anesthesia has subsided.

Adverse left ventricular (LV) remodeling after acute myocardial infarction is characterized by LV dilatation and development of a fibrotic scar, and is a critical factor for the prognosis of subsequent development of heart failure. Although myofiber organization is recognized as being important for preserving physiological cardiac function and structure, the anatomical features of injured myofibers during LV remodeling have not been fully defined. In a mouse model of ischemia–reperfusion (I/R) injury induced by left anterior descending coronary artery ligation, our previous histological assays demonstrated that broad fibrotic scarring extended from the initial infarct zone to the remote zone, and was clearly demarcated along midcircumferential myofibers. Additionally, no fibrosis was observed in longitudinal myofibers in the subendocardium and subepicardium. However, a histological analysis of tissue sections does not adequately indicate myofiber injury distribution throughout the entire heart. To address this, we investigated patterns of scar formation along myofibers using three‐dimensional (3D) images obtained from multiple tissue sections from mouse hearts subjected to I/R injury. The fibrotic scar area observed in the 3D images was consistent with the distribution of the midcircumferential myofibers. At the apex, the scar formation tracked along the myofibers in an incomplete C‐shaped ring that converged to a triangular shape toward the end. Our findings suggest that myocyte injury after transient coronary ligation extends along myofibers, rather than following the path of coronary arteries penetrating the myocardium. The injury pattern observed along myofibers after I/R injury could be used to predict prognoses for patients with myocardial infarction., In a mouse model of ischemia–reperfusion injury induced by left anterior descending coronary artery ligation, three‐dimensional images of myocardial scarring obtained from tissue sections (solid yellow area) indicate that the scar sequentially extends from the base to the apex in the midcardium. At the apex, the scar formation tracks along the myofibers in an incomplete C‐shaped ring that converges to a triangular shape toward the end. These findings suggest that myocyte injury after transient coronary ligation extends along myofibers, rather than following the path of coronary arteries penetrating the myocardium.

The first ophthalmologic complication in conjunction with a dental anesthesia was reported in 1936. The objective of the present study was a detailed analysis of case reports about that topic.After conducting a literature search in PubMed this study analyzed 108 ophthalmologic complications following intraoral local anesthesia in 65 case reports with respect to patient-, anesthesia-, and complication- related factors.The mean age of the patients was 33.8 years and females predominated (72.3%). The most commonly reported complication was diplopia (39.8%), mostly resulting from paralysis of the lateral rectus muscle. Other relatively frequent complications included ptosis (16.7%), mydriasis (14.8%) and amaurosis (13%). Ophthalmologic complications were mainly associated with block anesthesia of the inferior alveolar nerve (45.8%) or the posterior superior alveolar nerve (40.3%). Typically, the ophthalmologic complications in conjunction with intraoral local anesthesia had an immediate to short onset, and disappeared as the anesthesia subsided.The increased number of ophthalmologic complications after intraoral local anesthesia in females may suggest a gender effect. Double vision (diplopia) is the most frequently described complication, which is usually completely reversible like the other reported ophthalmologic complications.

The purpose of this study was to determine whether the morphology of the mandible differed in subjects of diverse ethnic origin exhibiting Class III malocclusions. Lateral cephalographs of 147 children of either Korean or European-American descent aged between 5 and 11 years were compared. The cephalographs were subdivided into seven age- and sex-matched groups, traced, and eight mandibular homologous landmarks digitized. Average mandibular geometries, scaled to an equivalent size, were computed using Procrustes superimposition and subjected to ANOVA. Graphical analysis using a colour-coded finite element (FEM) programme was used to localize differences in morphology. Results indicated that the overall mean Korean and European-American mandibular configurations differed statistically (P0.001) and statistical difference was maintained at all age-wise comparisons. Comparing Korean and European-American Class III mandibular configurations for local size-change, FEM analysis revealed that the Korean condylar and mental regions generally were smaller (approximately 15-20 per cent decrease in size, respectively). However, an antero-posterior increase in the size of the mandibular corpus was most apparent in the incisor alveolus region (approximately 35 per cent increase in size). For shape-change, the Korean and European-American mandibular configurations were fairly isotropic except in the symphyseal and incisor alveolus regions. Dissimilarities in mandibular morphology are identifiable particularly in the dento-alveolar regions in subjects of diverse ethnic origin exhibiting Class III malocclusions. These differences may reflect genetic and/or environmental influences that might determine the severity and prevalence of the condition, and its subsequent clinical management.

During a routine physical examination of an adult female with a history of breast cancer and cervical lymphadenopathy, a mass was noted in the right supraclavicular region. The mass was unilateral and easily palpable along the superior border near the median aspect of the clavicle. Plain film radiography, performed to determine whether the mass represented an enlarged jugulo-omohyoid lymph node, revealed an elongated opaque mass in this region. Computed tomographic (CT) and magnetic resonance (MR) images were subsequently obtained. Sequential axial CT scans revealed a cylindrical mass that appeared to be independent of contiguous muscles, including the sternocleidomastoid, anterior, and middle scalene muscles. This mass attached inferiorly to the clavicle and superiorly to the transverse process of the sixth cervical vertebra. Sagittal, coronal, and axial MR scans confirmed the presence of a well-defined superficial mass. It is concluded that the mass represents a levator claviculae (cleidocervical) muscle. This observation underscores the importance of understanding soft tissue variants that may be encountered during a routine physical examination. Clin. Anat. 13:298–301, 2000. © 2000 Wiley-Liss, Inc.

Quantitative measures of staining distributions are important to compare the presence and patterns of cells or macromolecules. Typically, achromatic thresholding systems are used to compare staining distributions. Achromatic video signals, however, lack sufficient resolution to identify and compare chromatic changes. The purpose of this study is to describe a full color system for analysis of chromatic staining distributions. The hardware system includes a Leitz Diaplan microscope, video camera, GVP videoboard and Amiga 3000 computer. Software was developed in "C" to partition the video signal into hue (H), saturation (S) and value (V). Also, percentage of stained area was determined. Kodak color filters were used to assess the accuracy and precision of the system. Craniofacial tissues were stained with varying concentrations of toluidine blue and primary anti-BrdU antibodies. HSV and the percentage of stained areas were determined and displayed low coefficients of error. HSV values also performed as expected for standard filters as well as cellular staining concentrations. This system is easily implemented and should be useful for comparing chromatic changes with any color resulting from histochemical or immunohistochemical procedures.

The craniofacial region of the Brachyrrhine (Br) mouse is characterized by a retruded midface. The cellular mechanism causing this growth deficiency is unknown. However, the cranial base is foreshortened in adult Br mice. The purpose of this study was to determine whether the spatial and temporal patterns of cellular proliferation in the cranial base (CB) differ between normal (C3H/HeJ) and Br mutant (3H1 Br/+) embryonic mice. Twenty-four dams were injected (3)H thymidine (5 microCi/gram body weight) and 15 embryos from each group were collected at Theiler stages 23, 25, and 27 (15, 17, and 19 days of gestation). Serial sections from each head were processed with routine autoradiography. Labelling indices (LI) were determined for each specimen and cellular proliferation maps were generated for each age group. LI patterns within and between groups were compared statistically. Results showed that cellular proliferation in the CB of normal embryos displayed a time- and position-dependent pattern, characteristic of transient growth sites (TGS). Generally, as age increases, cellular proliferative activities decrease gradually (from an average LI of 11.4 +/- 5.7% at stage 23 to 4.4 +/- 2.2% at stage 27), and the number of the TGS decreases in the presumptive nasal septal region and increases in presumptive sphenoethmoidal area with age, indicating the existence of cellular subpopulations in the CB. Cellular proliferation in the CB of the Br mutant displays a different growth pattern compared to the normal condition. Deficiencies in cellular proliferation exist mainly in the presumptive sphenoethmoidal area of the CB. The results indicate that the TGS play an important role in the normal morphogenesis of the CB, and abnormalities in their timing and/or position may be responsible for the dysmorphology of the midface in the Br mutant.

A well-developed anomalous muscle within the forearm flexor compartment was discovered during a routine cadaveric dissection. The identified muscle originated from the intercompartmental septum on the medial side of the forearm just proximal to the wrist joint and inserted on the proximal phalanx of the fifth digit. When stressed, the tendon of the muscle produced flexion of the metacarpophalangeal joint of the fifth digit. Contiguous muscles, including the flexor digitorum profundus, displayed normal morphology. The muscle appeared to be an accessory belly of flexor digitorum profundus. The combination of an accessory flexor digitorum profundus muscle belly acting on the metacarpophalangeal joint of the little finger has not been previously reported. Based on its origin, insertion, and action we have named this variant accessory flexor digiti minimi profundus. This muscular variant could have clinical relevance, possibly affecting ulnar nerve function and circulation in the hand. Clin. Anat. 11:55–59, 1998. © 1998 Wiley-Liss, Inc.

The purpose of this study was to determine whether the morphology of the midface differed in subjects with a retrognathic midfacial appearance (Class III malocclusions) using a combination of morphometric and cephalometric analyses. After obtaining appropriate consent, lateral cephalographs of 133 children of European-American descent, ages 5‐11 years, were compared: 73 had Class III malocclusion, 60 had normal (Class I) occlusion. The cephalographs were traced and subdivided into seven age- and sex-matched groups. Average geometries based upon seven nodes (pterygoid point, PTS; rhinion, RO; posterior nasal spine, PNS; midpalatal point, MPP; anterior nasal spine, ANS; subspinale, A; prosthion, Pr), scaled to an equivalent size, were compared using a Procrustes routine. Euclidean distance matrix analysis (EDMA) was employed to localize differences in morphology. Bivariate analyses on unscaled data utilizing nine linear and six angular measurements were also undertaken. Results from Procrustes and EDMA analyses indicated that although the overall midfacial configurations differed statistically ( P , 0.05), only about half of the seven age sub-groups maintained significance. Similarly, only four of the nine linear measures (PNS-MPP, MPP-ANS, A-Pr and PTS-RO) and two of the six angular parameters (PTS-RO-ANS and ANS-A-Pr) tested were significantly different (P , 0.05). Therefore, midfacial morphometric variability and morphological diversity may mask statistical differences. It is concluded that the midface may be the defining craniofacial component in the final appearance of Class III malocclusions compared to other craniofacial components, including the cranial base and mandible. Clin. Anat. 11:162‐ 170, 1998. r 1998 Wiley-Liss, Inc.

This study determines deformations that contribute to a Class III mandibular morphology, employing thin-plate spline (TPS) analysis. A total of 133 lateral cephalographs of prepubertal children of European-American descent with either a Class I molar occlusion or a Class III malocclusion were compared. The cephalographs were traced and checked, and eight homologous landmarks on the mandible were identified and digitized. The datasets were scaled to an equivalent size and subjected to statistical analyses. These tests indicated significant differences between average Class I and Class III mandibular morphologies. When the sample was subdivided into seven age and sex-matched groups statistical differences were maintained for each group. TPS analysis indicated that both affine (uniform) and non-affine transformations contribute towards the total spline, and towards the average mandibular morphology at each age group. For non-affine transformations, partial warp 5 had the highest magnitude, indicating large-scale deformations of the mandibular configuration between articulare and pogonion. In contrast, partial warp 1 indicated localized shape changes in the mandibular symphyseal region. It is concluded that large spatial-scale deformations affect the body of the mandible, in combination with localized distortions further anteriorly. These deformations may represent a developmental elongation of the mandibular corpus antero-posteriorly that, allied with symphyseal changes, leads to the appearance of a Class III prognathic mandibular profile.

The significance of the cranial base in the development of Class III malocclusion remains uncertain. The purpose of this study was to determine whether the form of the cranial base differs between prepubertal Class I and Class III subjects. Lateral cephalographs of 73 children of European-American descent aged between 5 and 11 years with Class III malocclusion were compared with those of their counterparts with a normal, Class I molar occlusion. The cephalographs were traced, checked, and subdivided into seven age- and sex-matched groups. Average geometries, scaled to an equivalent size, were generated based on 13 craniofacial landmarks by means of Procrustes analysis, and these configurations were statistically tested for equivalence. Bivariate and multivariate analyses utilizing 5 linear and angular measurements were undertaken to corroborate the Procrustes analysis. Graphical analysis, utilizing thin-plate spline and finite element methods, was performed for localization of differences in cranial base morphology. Results indicated that cranial base morphology differed statistically for all age-wise comparisons. Graphical analysis revealed that the greatest differences in morphology occurred in the posterior cranial base region, which generally consisted of horizontal compression, vertical expansion, and size contraction. The sphenoidal region displayed expansion, while the anterior regions showed shearing and local increases in size. It is concluded that the shape of the cranial base differs in subjects with Class III malocclusion compared with the normal Class I configuration, due in part to deficient orthocephalization, or failure of the cranial base to flatten during development.

Cephalothoracopagus twinning is extremely rare, and it is characterized by fusion of the head and thorax, two separate spines, pelves, and fore- and hindlimbs.In this case study, we describe cephalothoracopagus twinning in an embryonic mouse displaying a large but exencephalic head, median facial cleft, a single eye, and a second hindbrain rotated roughly 90° from a second spinal cord. There is a bony connection joining the clavicles, resulting in merged asternal thoracic cavities containing two hearts and four lungs. The abdominal cavities contain double caudal digestive tract structures, but a single esophagus and stomach.There are several proposed theories regarding the mechanism of spontaneous conjoined twinning; however, the specific mechanisms are still largely unknown. In this report, we highlight the morphological features in a murine example of cephalothoracopagus twinning, furthering our understanding of this rare occurrence while also demonstrating developmental morphogenesis consistent with that reported for human conjoined twins.

PURPOSE The anterior maxilla, sometimes also called premaxilla, is an area frequently requiring surgical interventions. The objective of this observational study was to identify and assess accessory bone channels other than the nasopalatine canal in the anterior maxilla using limited cone beam computed tomography (CBCT). METHODS A total of 176 cases fulfilled the inclusion criteria comprising region of interest, quality of CBCT image, and absence of pathologic lesions or retained teeth. Any bone canal with a minimum diameter of 1.00 mm other than the nasopalatine canal was analyzed regarding size, location, and course, as well as patient gender and age. RESULTS A total of 67 accessory canals ≥1.00 mm were found in 49 patients (27.8%). A higher frequency of accessory canals was observed in males (33.0%) than in females (22.7%) (p = 0.130). Accessory canals occurred more frequently in older rather than younger patients (p = 0.115). The mean diameter of accessory canals was 1.31 ± 0.26 mm (range 1.01-2.13 mm). Gender and age did not significantly influence the diameter. Accessory canals were found palatal to all anterior teeth, but most frequently palatal to the central incisors. In 56.7%, the accessory canals curved superolaterally and communicated with the ipsilateral alveolar extension of the canalis sinuosus. CONCLUSIONS The study confirms the presence of bone channels within the anterior maxilla other than the nasopalatine canal. More than half of these accessory bone canals communicated with the canalis sinuosus. From a clinical perspective, studies are needed to determine the content of these accessory canals.

Cleft palate is a common congenital birth defect in humans. In mammals, the palatal tissue can be distinguished into anterior bony hard palate and posterior muscular soft palate that have specialized functions in occlusion, speech or swallowing. Regulation of palate development appears to be the result of distinct signaling and genetic networks in the anterior and posterior regions of the palate. Development and maintenance of expression of these region-specific genes is crucial for normal palate development. Numerous transcription factors and signaling pathways are now recognized as either anterior- (e.g., Msx1, Bmp4, Bmp2, Shh, Spry2, Fgf10, Fgf7, and Shox2) or posterior-specific (e.g., Meox2, Tbx22, and Barx1). Localized expression and function clearly highlight the importance of regional patterning and differentiation within the palate at the molecular level. Here, we review how these molecular pathways and networks regulate the anterior–posterior patterning and development of secondary palate. We hypothesize that the anterior palate acts as a signaling center in setting up development of the secondary palate.