Chitayat syndrome: hyperphalangism, characteristic facies, hallux valgus and bronchomalacia results from a recurrent c.266A>G p.(Tyr89Cys) variant in the ERF gene.

BACKGROUND: In 1993, Chitayat et al., reported a newborn with hyperphalangism, facial anomalies, and bronchomalacia. We identified three additional families with similar findings. Features include bilateral accessory phalanx resulting in shortened index fingers; hallux valgus; distinctive face; respiratory compromise. OBJECTIVES: To identify the genetic aetiology of Chitayat syndrome and identify a unifying cause for this specific form of hyperphalangism. METHODS: Through ongoing collaboration, we had collected patients with strikingly-similar phenotype. Trio-based exome sequencing was first performed in Patient 2 through Deciphering Developmental Disorders study. Proband-only exome sequencing had previously been independently performed in Patient 4. Following identification of a candidate gene variant in Patient 2, the same variant was subsequently confirmed from exome data in Patient 4. Sanger sequencing was used to validate this variant in Patients 1, 3; confirm paternal inheritance in Patient 5. RESULTS: A recurrent, novel variant NM_006494.2:c.266A>G p.(Tyr89Cys) in ERF was identified in five affected individuals: de novo (patient 1, 2 and 3) and inherited from an affected father (patient 4 and 5). p.Tyr89Cys is an aromatic polar neutral to polar neutral amino acid substitution, at a highly conserved position and lies within the functionally important ETS-domain of the protein. The recurrent ERF c.266A>C p.(Tyr89Cys) variant causes Chitayat syndrome. DISCUSSION: ERF variants have previously been associated with complex craniosynostosis. In contrast, none of the patients with the c.266A>G p.(Tyr89Cys) variant have craniosynostosis. CONCLUSIONS: We report the molecular aetiology of Chitayat syndrome and discuss potential mechanisms for this distinctive phenotype associated with the p.Tyr89Cys substitution in ERF.

Self-reported oral behaviour habits in hyperdivergent and normodivergent facial types.

The relationship between facial morphology and jaw function remains controversial. The purpose of this study was to investigate differences in self-reported oral behaviour habits between individuals with normodivergent and hyperdivergent facial types. Some 80 cases and controls were individually matched on age, sex ethnicity and treatment stage. The participants were recruited from an orthodontic clinic, and included both adolescents and adults. Habitual oral activity was assessed using the Oral Behaviour Checklist (OBC) based on their experiences in the past 4 weeks. Univariate and bivariate analyses were performed. The sample had a mean age of 17·2 years (SD = 4·6; range = 12-49 years), and was predominantly female (65·0%) and of New Zealand European origin (91·3%). The prevalence of reporting one or more frequently performed habitual muscular behaviour in either study group was over 85% (P > 0·05). There was no difference in total OBC score between the hyperdivergent (25·6; SD: 9·0) and normodivergent group (25·3; SD: 9·9). Moreover, there was no difference in the prevalence of either nocturnal or daytime oral behaviours between the two groups. While this study did not include any objective measures of functional or habitual activity, we found no differences in self-reported oral behaviour habits between normodivergent and hyperdivergent individuals. The findings do not support an association between vertical facial form and habitual muscular activity.

Three-dimensional finite element analysis of maxillary protraction with labiolingual arches and implants.

INTRODUCTION: In this study, we aimed to evaluate the effects of maxillary protraction using traditional labiolingual arches and implant-type protraction devices before orthopedic treatment of patients with skeletal Class III malocclusion. METHODS: A 3-dimensional finite element model of the maxillofacial bones with high biologic similarity and including the sutures was constructed. Through stress and displacement calculations, a biomechanical study was performed for the maxillofacial bones, mandible, and sutures. RESULTS: We quantified detailed changes in the sutures with 2 protraction methods to analyze their effects on the growth of the maxillofacial bones. CONCLUSIONS: (1) The labiolingual arch is suitable for skeletal Class III patients with crossbite and deep overbite. The frontomaxillary and zygomaticomaxillary sutures played major roles in the forward displacement and counterclockwise rotation of the maxilla. The temporozygomatic and pterygopalatine sutures did not change significantly. (2) The implant type of protraction device is suitable for skeletal Class III patients with crossbite and open bite. Both the frontomaxillary and zygomaticomaxillary sutures played decisive roles in the forward displacement and clockwise rotation of maxilla. The temporozygomatic and pterygopalatine sutures showed small changes. (3) The labiolingual arch caused less stimulatory growth on the maxilla, whereas the implant caused greater stimulatory growth on the maxilla. Protraction with the labiolingual arch is more suitable for early skeletal Class III patients at a younger age; protraction with an implant is applicable to skeletal Class III patients in the late mixed dentition or early permanent dentition.

[The mechanical properties of the bone tissue from the middle facial region].

The objective of the present work was to study age-related features of the reaction of the maxillary sinus cavity walls to a variety of impacts associated with the surgical interventions. To this effect, a variety of stress-strain conditions were simulated that are known to arise in the maxillary sinus cavity walls under the action of different force vectors taking into consideration the age-specific peculiarities of the mechanical structure of the bone tissue. The 3D model of the maxillary sinus cavity was built up based on the results of spiral computed tomography with the use of the Solid Works 2012 software package (USA). The finite element method (FEM) was employed to construct the grid. Three variants of force application were simulated, one to the canine fossa region, another to the upper portion of the alveolar process at the border between the upper and lower walls of the sinus, and the third to the anterior part of the inferior nasal passage. The study has demonstrated that the bone wall of the maxillary sinus differently responds to the impacts of similar magnitude depending on the application point and age-related physical and mechanical properties of the bone tissue. This finding should be taken into account in the choice of the optimal surgical approach to the maxillary sinus. It was calculated that endonasal interventions should be preferred for the treatment of patients above 60 years of age as the minimally injurious ones to the bone tissue. Moreover, special caution is needed when the intervention is performed beneath the canine fossa, where the bone is extremely fragile and the risk of injury extension to the floor of the maxillary sinus is especially high.

SURGICAL TREATMENT OF UPPER AND MIDDLE FACIAL ZONE TRAUMAS IN PROGRESS OF CONCOMITANT TRAUMATIC CRANIOFACIAL INJURIES.

In 2012-2015, 207 patients with concomitant craniofacial injuries, who underwent surgical treatment, were observed; among them 176 were men and 31- women. Age of the patients ranged from 16 to 60 years. According to localization and severity of trauma and a priority of surgical intervention, the patients conventionally were divided into 3 groups by the authors: I group (65 patients) - craniofacial injuries; the skull as well as upper and middle areas of face (subcranial and frontobasal fractures) were affected (fractured). II group (80 patients) - severe traumatic injuries of upper and especially middle zones of the face, accompanied with closed craniocerebral trauma, no need in neurosurgery. III group (62 patients) -on the background of serious head traumas, the injuries of face bones were less severe (injury of one or two anatomic areas with displacement of fractured fragments but without bone tissue defects) According to the obtained results a priority was always given to the neurosurgery (vital testimony).The reconstructive surgeries on face skeleton was conducted in combination involving neurosurgeons (I group patients). Reconstructive surgeries of facial bones were conducted in the patients of II group, immediately or at primary deferred period of time but in the patients of III group the surgical procedures for removal of early secondary or traumatic residual fractures have been performed. Reposition of the fractured facial bone fragments was performed in an open way and fixation was carried out by titanium plates and mesh cage (at bone tissue defect). For prevention and elimination of post-traumatic inflammatory processes, the final stage of surgical intervention was: sanation of nasal accessory sinuses and catheterization (5-7 days) of external carotid arteries for administration of antibiotics and other medical preparations. Early and differentiated approach to face injuries, worsening in the course of craniocephalic trauma was not revealed in any patient; there was no evidence of development inflammatory processes in traumatic regions; esthetic and functional results obtained after the surgeries of maxillofacial area were assessed as good and satisfactory.

Premature closure of the spheno-occipital synchondrosis in Pfeiffer syndrome: a link to midface hypoplasia.

The spheno-occipital synchondrosis (SOS) is a critical component of midfacial and cranial base growth. Premature closure has been associated with midface hypoplasia in animal models and syndromic craniosynostosis subpopulations with Apert and Muenke syndromes. To link premature SOS closure and midface hypoplasia in patients with Pfeiffer syndrome, a retrospective case-control study was performed in patients treated at a large craniofacial center between 1982 and 2012 diagnosed with Pfeiffer syndrome. At least 1 computed tomography (CT) scan was required to assess SOS patency. Age-/sex-matched control CT scans were also assessed for SOS patency. Three independent reviewers with high interrater reliability (κ = 0.88) graded SOS patency as open, partially closed, or completely closed. Wilcoxon rank sum test compared the Pfeiffer patients with control subjects. A total of 63 CT scans in 16 patients with Pfeiffer syndrome, all with midface hypoplasia, and 63 age-/sex-matched control scans, none of whom had midface hypoplasia, met inclusion criteria. Earliest partial SOS closure in patients with Pfeiffer syndrome was seen at 5 days compared with control subjects at 7.07 years. Earliest age at complete fusion was 2.76 years in the Pfeiffer cohort and 12.74 years in control subjects. Average age at partial closure was significantly younger (4.99 ± 3.33 years; n = 31 scans) in patients with Pfeiffer syndrome compared with control subjects (10.92 ± 3.53 years) (P = 0.0005), whereas average age at complete closure (11.90 ± 7.04 years) was not significantly different than that in control subjects (16.07 ± 3.39 years). Although definitive causality cannot be concluded, a strong correlation exists between midface hypoplasia and premature SOS closure in Pfeiffer syndrome.

Video analysis of the biomechanics of a bicycle accident resulting in significant facial fractures.

INTRODUCTION: This study aimed to use video analysis techniques to determine the velocity, impact force, angle of impact, and impulse to fracture involved in a video-recorded bicycle accident resulting in facial fractures. Computed tomographic images of the resulting facial injury are presented for correlation with data and calculations. To our knowledge, such an analysis of an actual recorded trauma has not been reported in the literature. MATERIALS AND METHODS: A video recording of the accident was split into frames and analyzed using an image editing program. Measurements of velocity and angle of impact were obtained from this analysis, and the force of impact and impulse were calculated using the inverse dynamic method with connected rigid body segments. These results were then correlated with the actual fracture pattern found on computed tomographic imaging of the subject's face. RESULTS: There was an impact velocity of 6.25 m/s, impact angles of 14 and 6.3 degrees of neck extension and axial rotation, respectively, an impact force of 1910.4 N, and an impulse to fracture of 47.8 Ns. These physical parameters resulted in clinically significant bilateral mid-facial Le Fort II and III pattern fractures. DISCUSSION: These data confer further understanding of the biomechanics of bicycle-related accidents by correlating an actual clinical outcome with the kinematic and dynamic parameters involved in the accident itself and yielding a concrete evidence of the velocity, force, and impulse necessary to cause clinically significant facial trauma. These findings can aid in the design of protective equipment for bicycle riders to help avoid this type of injury.

Dynamic changes of facial skeletal fractures with time.

To investigate the characteristics of imaging changes with time of facial fractures, patients with facial fractures who had computed tomographic scan were enrolled including 500 patients who were divided into six groups based on the time of scanning: super early (<3 d), early (4-7 d), early-to-medium (8-14 d), medium (15-21d), medium-to-late (22d-2 months) and late stage (>2 months). The data were compared and analyzed. Forty two patients with frontal bone fractures had high-energy impact as the reason of fractures. The fracture line was clear and sharp within one week but blunt and sclerotic due to bone absorption at 2-3 weeks, and might exist for a long time. All patients had soft tissue swelling and paranasal sinus effusion at 1-2 weeks after injury. Air might gather in the adjacent soft tissues and/or intracranially within 3 days of injury if the fracture involved the frontal or other sinuses. Twelve of the 42 patients (28.6%) had intracranial hematoma, and five (11.9%) had epidural effusion. Subarachnoid hemorrhage was mostly absorbed within one week while epidural hematoma was completely absorbed over 3 weeks. Significant changes (P < 0.05) in the fracture lines, effusion of paranasal sinuses, soft tissue swelling and pneumocephalus were observed during the study period. For patients with medial orbital wall fractures, the fracture line was sharp and clear at early stages with concurrent sphenoid sinus effusion, and the fracture line became depressed 3 weeks later with disappearance of sphenoid sinus effusion. Significant changes (P < 0.05) were observed in the sharp fracture line, soft tissue swelling, sphenoid sinus effusion and smooth depression at fracture sites. For nasal fractures, the fracture line was sharp and clear at early stages with concurrent soft tissue swelling which disappeared one week later. The fracture line became smooth three weeks later. A significant (P < 0.05) difference was demonstrated in the changes of fracture line and soft tissue swelling with time. In conclusion, facial fractures have some dynamic alterations with time and identification of these characteristics may help reaching a correct clinical diagnosis with regard to fracture severity and time.

Maxillary protraction with and without maxillary expansion: a finite element analysis of sutural stresses.

INTRODUCTION: In this finite element study, we compared the stress patterns along the various craniofacial sutures with maxillary protraction with and without expansion. METHODS: Two 3-dimensional analytic models were developed, 1 simulating maxillary protraction and the other simulating maxillary protraction with expansion. The model consisted of 108799 10 node solid 92 elements (tetrahedron), 193633 nodes, and 580899 degrees of freedom. RESULTS: The overall stresses after maxillary protraction with maxillary expansion were significantly higher than with a facemask alone. The magnitude of stress on the craniofacial sutures with maxillary protraction alone was in the range of a few millinewtons per square millimeter, whereas, with maxillary protraction with maxillary expansion, the stresses ranged from a few newtons per square millimeter to a few hundred newtons per square millimeter. The pattern of stress distribution also differed with the 2 treatment modalities as did the sutures experiencing maximum and minimum stresses. CONCLUSIONS: The osteogenic potential of such low stresses after maxillary protraction can be questioned. High stresses generated in various craniofacial sutures after maxillary protraction with expansion are responsible for disrupting the circummaxillary sutural system and presumably facilitating the orthopedic effect of the facemask.

Sutural strain in orthopedic headgear therapy: a finite element analysis.

INTRODUCTION: The goal of this study was to analyze the strains induced in the sutures of the midface and the cranial base by headgear therapy involving orthopedic forces. Does the mechanical signal induced in the sutures sufficiently account for a growth-influencing effect? METHODS: A finite element model of the viscerocranium and the neurocranium was used. It consisted of 53,555 tetrahedral elements and 97,550 nodes. The strain induced in the sutures of the cranial base and the midface when applying orthopedic headgear forces of 5 and 10 N was computed and recorded with an interactive measurement tool. RESULTS: The magnitude and the distribution of the measured strains depended on the level and the direction of the acting force. Overall, the strain values measured at the sutures of the midface and the cranial base were moderate. The measured peak values at a load of 5 N per side were usually just below 20 microstrain irrespective of the force direction. A characteristic distribution of strain values appeared on the anatomical structures of the midface and the cranial base for each vector direction. The measurements based on the finite element method provided a good overview of the approximate magnitudes of sutural strains with orthopedic headgear therapy. The signal arriving in the sutures is apparently well below threshold, since the maximum measured strains in most sutures were about 100 fold lower than the minimal effective strain. A skeletal effect of the orthopedic headgear due to a mechanical effect on sutural growth cannot be confirmed from these results. CONCLUSIONS: The good clinical efficacy of headgear therapy with orthopedic forces is apparently based mainly on dentoalveolar effects, whereas the skeletal effect due to inhibition of sutural growth is somewhat questionable.

Vertical facial dimensions linked to abnormal foot motion.

BACKGROUND: Twenty-two children from Jiutepec, Mexico, were studied to determine whether a correlation exists among foot motion, the position of the innominates, and vertical facial dimensions (ie, the distances between the outer corners of the eyes [the exocanthions] and the ipsilateral outer margins of the lips). METHODS: Three null hypotheses were constructed and tested using the one-sample t test. Hypothesis A: there is no relationship between abnormal foot pronation and hip position; Hypothesis B: there is no relationship between hip position and vertical facial dimensions; and Hypothesis C: there is no relationship between abnormal foot pronation and vertical facial dimensions. RESULTS: The three null hypotheses were rejected. CONCLUSIONS: An ascending foot cranial model was theorized to explain the findings generated from this study: 1) due to the action of gravity on the body, abnormal foot pronation (inward, forward, and downward rotation) displaces the innominates anteriorly (forward) and downward, with the more anteriorly rotated innominate corresponding to the more pronated foot; 2) anterior rotation of the innominates draws the temporal bones into anterior (internal) rotation, with the more anteriorly rotated temporal bone being ipsilateral to the more anteriorly rotated innominate bone; 3) the more anteriorly rotated temporal bone is linked to an ipsilateral inferior cant of the sphenoid and superior cant of the maxilla, resulting in a relative loss of vertical facial dimensions; and 4) the relative loss of vertical facial dimensions is on the same side as the more pronated foot.

Interrelation between occlusal findings and orofacial myofunctional status in primary and mixed dentition: Part III: Interrelation between malocclusions and orofacial dysfunctions.

AIM: It was the purpose of this study to analyze the relationship between selected types of malocclusion and specific types of static and dynamic orofacial dysfunction and to compare the results with subjects presenting regular occlusion. We aimed to identify which orthodontic and functional symptoms in early dentition would lead to malocclusion later on. SUBJECTS AND METHODS: Occlusal relations and myofunctional status were evaluated in 3,041 children. We diagnosed dynamic and static myofunctional disorders as well as oral habits by means of functional examinations. RESULTS: No orofacial dysfunctions were found in 11.2% of the children with primary dentition and in 10.2% of the children with early mixed dentition. We observed no correlation between the existence of distoclusion and functional disorders. Lateral crossbite in mixed dentition, as well as increased overjet and frontal open bite in primary and early mixed dentitions appeared significantly more frequently in children with orofacial dysfunctions. Individuals with frontal open bite, lateral crossbite, reduced and increased overjet presented static dysfunctions significantly more frequently than those in dentitions with normal occlusion. Dynamic dysfunctions were significantly more prevalent in subjects with frontal open bite and lateral crossbite than in those with normal occlusion. CONCLUSIONS: Our results enable us to prognosticate which children risk future orthodontic problems. Any child presenting one of the four occlusal disorders plus one static or two dynamic dysfunctions is a child more likely to develop orthodontic problems later on. Orthodontic prevention and early treatment must include functional rehabilitation so as to eliminate or at least diminish those factors causing undesirable developments.

Impact of postmenopausal osteoporosis on the oral and maxillofacial surgery patient.

With aging, there is a loss of skeletal mass in women and men, but the rate of loss accelerates in perimenopausal women. With the loss of bone mass there is increased risk for fracture in the axial and appendicular skeleton. The mandible and maxilla also experience age-related declines in some parameters of architecture and trabecular pattern, but those do not seem to be directly associated with fracture risk. Although the literature is controversial regarding the generalizability of the impact of systemic osteoporosis on the oral/maxillofacial patient, it is prudent to give consideration to an individual patient's osteoporosis status, risk, and anti-osteoporosis therapies when planning oral and maxillofacial surgical procedures.

Stress and displacement patterns in the craniofacial skeleton with rapid maxillary expansion-a finite element method study.

BACKGROUND: Rapid maxillary expansion (RME), indicated in the treatment of maxillary deficiency directs high forces to maxillary basal bone and to other adjacent skeletal bones. The aim of this study is to (i) evaluate stress distribution along craniofacial sutures and (ii) study the displacement of various craniofacial structures with rapid maxillary expansion therapy by using a Finite Element model. METHODS: An analytical model was developed from a dried human skull of a 12 year old male. CT scan images of the skull were taken in axial direction parallel to the F-H plane at 1 mm interval, processed using Mimics software, required portion of the skull was exported into stereo-lithography model. ANSYS software was used to solve the mathematical equation. Contour plots of the displacement and stresses were obtained from the results of the analysis performed. RESULTS: At Node 47005, maximum X-displacement was 5.073 mm corresponding to the incisal edge of the upper central incisor. At Node 3971, maximum negative Y-displacement was -0.86 mm which corresponds to the anterior zygomatic arch, indicating posterior movement of craniofacial complex. At Node 32324, maximum negative Z-displacement was -0.92 mm representing the anterior and deepest convex portion of the nasal septum; indicating downward displacement of structures medial to the area of force application. CONCLUSIONS: Pyramidal displacement of maxilla was evident. Apex of pyramid faced the nasal bone and base was located on the oral side. Posterosuperior part of nasal cavity moved minimally in lateral direction and width of nasal cavity at the floor of the nose increased, there was downward and forward movement of maxilla with a tendency toward posterior rotation. Maximum von Mises stresses were found along midpalatal, pterygomaxillary, nasomaxillary and frontomaxillary sutures.

Maxillofacial trauma: managing potentially dangerous and disfiguring complex injuries [digest].

Patients with maxillofacial trauma require a careful evaluation due to the anatomical proximity of the maxillofacial region to the head and neck. Facial injuries can range from soft-tissue lacerations and nondisplaced nasal fractures to severe, complex fractures, eye injuries, and possible brain injury. Though the Advanced Trauma Life Support (ATLS) guidelines provide a framework for the management of trauma patients, they do not provide a detailed reference for many subtle or complex facial injuries. This issue adds a more comprehensive and systematic approach to the secondary survey of the maxillofacial area and emergency department management of injuries to the face. In addition to an overall review of maxillofacial trauma pathophysiology, associated injuries, and physical examination, this review will also discuss relevant imaging, treatment, and disposition plans. [Points & Pearls is a digest of Emergency Medicine Practice].

Bone and aging: effects on the maxillofacial skeleton.

The originally balanced system of normal bone metabolism with an equilibrium of bone resorption and bone formation experiences involutionary changes along with increasing age. This article provides an overview on the effects of aging on bone, in particular on the bone of the maxillofacial skeleton. It explains differences between the postmenopausal type and the senile type of osteoporosis, deals with age-related morphologic changes of bone, mechanisms leading to age-related changes, depicts bones at high fracture risk in aging persons, analyses the reduced bone quantity and quality in cranial bone, and discusses the preservation of maxillofacial bone dimensions by implants. Therefore, research on wound healing, in particular bone healing, and on the regenerative potential of tissue of mesenchymal origin is of major interest and will eventually translate into improved care for patients during daily clinical routine.

Concepts in a multiprong approach to photoaging.

Photoaging is a multisystem degenerative process that involves the skin and the skin support systems, including the bone, cartilage, and subcutaneous compartments. These structures provide the architectural support for the dermis, epidermis, and stratum corneum. A multiprong approach to photoaging involves reversing the undesirable changes in each of these structures. Dermatologists should become adept at treating all of the visible manifestations of photoaging.

Comparative cephalometric study between nasal and predominantly mouth breathers.

AIM: To evaluate the possible correlation between the respiratory pattern in determining the craniofacial dimensions, using as baseline the Tweed-Merrifields cephalometric analysis, added to angle SN-GoGn and to Y axis angle. METHODOLOGY: The selected sample to this study comprised 50 teleradiographies taken in lateral and natural positions of the head in young female patients at the age of 9 to 12 years, presenting mean age of 10 years and 5 months and Class 1 malocclusion. After diagnosis of respiratory pattern, the sample was divided into two groups: control group, 25 teleradiographies of nasal breathers in lateral and natural positions of the head; experimental group, 25 teleradiographies of predominantly mouth breathers in lateral and natural positions of the head. RESULTS: The results were submitted to descriptive analysis (mean and standard deviation), test F and "t" Student test with significance level of 5%. There was no significant difference between the group with nasal breathing and the group with predominantly mouth breathing for any of the studied variables.

Single and combination drug therapy for fetal hemoglobin augmentation in hemoglobin E-beta 0-thalassemia: Considerations for treatment.

Patients with hemoglobin E (Hb E)-beta 0-thalassemia, one of the most common hemoglobinopathies worldwide, could benefit from drugs that increase fetal and total hemoglobin levels and thereby decrease the need for transfusions. The long-term clinical outcome of such therapy, its hematologic effects, and which patients are likely to benefit from treatment are unknown. Consequently, the use of such drugs for Hb E-beta 0-thalassemia is limited, and countries where resources for safe and regular transfusion are scarce cannot benefit from them. In a multicenter trial of 42 patients treated with hydroxyurea for two years, almost half the patients demonstrated a significant increase in steady-state hemoglobin level. Drug toxicity was minimal. Combined treatment of hydroxyurea with erythropoietin benefited selected patients, but the addition of sodium phenyl butyrate was ineffective. After 5 years of follow-up, a subset of patients remained off transfusions. Hydroxyurea should be considered for a subset of Hb E-beta 0-thalassemia patients.

Dynamic Response of the Skull with Sinuses under Blunt Frontal Impact: A Three-Dimensional Computational Study.

The objective of this study is to analyze the biomechanical effects of sinuses in the skull on the facial impact response. Two models were built, where one had sinuses and the other had none. The models were verified using cadaver test data, including impacts to frontal bone, zygomatic bone, and maxillae. In the maxilla and zygoma impact, sinuses were found to have no significant effect on the global distribution of stress or stiffness of facial bones, and the influence was limited in local area. In forehead impact, the sinuses significantly affected the distribution of stress and strain in the skull due to its location in facial bones. The result shows that if the sinus is far away from the location of impact, its effect on the overall response of skull could be ignored. In addition, the distance between the region of interest and sinuses is another important parameter when studying the local effect of sinuses.