Age and Gender-related Morphometric Assessment and Degenerative Changes of Temporomandibular Joint in Symptomatic Subjects and Controls using Cone Beam Computed Tomography (CBCT): A Comparative Analysis

BACKGROUND

The temporomandibular joint diseases have been associated with various predisposing factors. Joint spaces, articular eminence height and inclination, and the shapes of the condylar and glenoid fossa have all been shown to vary in temporomandibular joint diseases (TMD) patients. Advanced imaging techniques like cone beam computed tomography (CBCT) have been employed to estimate these parameters.

AIMS AND OBJECTIVES

The aim of the current study was to investigate the condylar morphology, condylar and glenoid fossa shapes, and assessment of joint spaces, such as anterior, posterior, superior, lateral, and medial spaces, through CBCT slices in coronal and sagittal planes and compare them between the control group and TMD group.

MATERIALS AND METHODS

A cross-sectional study was planned where 80 joints in 40 patients were assessed for the above parameters; group I consisted of healthy patients, and group II included those with temporomandibular joint diseases (TMDs). The articular eminence height and inclination were assessed on the midsagittal section. The condylar changes and shapes of the glenoid fossa and condyles, as well as the joint spaces, were assessed on the selected coronal and sagittal sections.

RESULTS

The condylar fossa had a triangular shape in the TMJ group and an oval shape in the control group. The results were highly significant (P = 0.000**). A highly significant difference in morphological parameters, such as AJS, PJS, SJS, MJS, LJS, articular eminence height, and inclination, was found between the two groups (P = 0.000**). The association of morphological parameters, such as AJS, PJS, SJS, MJS, LJS, and articular eminence height and inclination were compared with condylar and glenoid fossa shapes, where the association of superior joint space and articular eminence inclination was observed. A highly significant difference was noted between the two groups with regard to all the parameters with P=0.00*.

CONCLUSION

The articular eminence inclination, as well as the superior joint space, were found to be associated with the glenoid and condyle fossa shapes in the TMJ group. These observations would, therefore, help in the early diagnosis of temporomandibular joint diseases.

A pilot investigation of condylar position and asymmetry in patients with unilateral posterior scissors-bite malocclusion based on three-dimensional reconstructive imaging technique

OBJECTIVE

Unilateral posterior scissors-bite (uPSB) malocclusion is common clinically. This study aimed to investigate the condylar morphological alterations and condyle-fossa relationship in patients with uPSB, through cone beam computed tomography (CBCT) and three-dimensional reconstructive imaging technique.

METHODS

A retrospective study was designed to comparatively analyze 95 patients with uPSB between July 2016 and December 2021. They were divided into three subgroups: 12 to 20, 21 to 30, and ≥ 31 years, according the age distribution. The morphological parameters regarding condyle, fossa, and joint space after three-dimensional reconstruction were measured and analyzed by a series of digital software. SPSS 26.0 software package was performed for statistical analysis on data sets, using paired t-test, one-way analysis of variance, Wilcoxon signed-rank sun test, Kruskal-Wallis H test, and Bonferroni correction.

RESULTS

The condylar volume (CV) of scissors-bite side was greater than that of the non-scissors-bite side (CV _A = 1740.68 ± 559.80 mm³ > CV _N = 1662.25 ± 524.88 mm³, P = 0.027). So was the condylar superficial area (CSA) (CSA _A = 818.71 ± 186.82 mm² > CSA _N = 792.63 ± 173.44 mm², P = 0.030), and the superior joint space (SJS) [SJS _A = 2.46 (1.61, 3.68) mm) > SJS _N = 2.01 (1.55, 2.87) mm), P = 0.018], and the anterior joint space (AJS) (AJS _A = 3.94 ± 1.46 mm > AJS _N = 3.57 ± 1.30 mm, P = 0.017). The constituent ratios of the different parts of the bilateral condyles were 23% on the posterior slope, 21% on the top, 20% on the anterior slope, 19% on the lateral slope and 17% on the medial slope, respectively.

CONCLUSION

Due to long-term abnormal occlusion of uPSB, the pathological bite force in temporomandibular joint would cause changes in the shape of the condyle. Among them, CV, CSA, SJS and AJS had significant changes in the scissors-bite status, which has the greatest damage to the posterior slope of the condyloid process.

Three-dimensional characteristics of temporomandibular joint morphology and condylar movement in patients with mandibular asymmetry

BACKGROUND

Investigating the morphological and functional effects on mandibular asymmetry (MA) is important not only to understand the developmental process of masticatory dysfunction, but also to provide suggestions for evidence-based occlusal treatment.

AIM

To evaluate three-dimensional temporomandibular joint (TMJ) morphology and its relationship to asymmetrical condylar movement in MA patients.

MATERIALS AND METHODS

Fifty subjects were divided into MA and control groups (n = 25 each) according to a menton deviation of 4 mm from the mid-sagittal plane. TMJ morphology (condyle, glenoid fossa and TMJ spaces) were evaluated using a three-dimensional analysis programme. Three-dimensional condylar movements (from the sagittal and horizontal planes) were recorded and measured by computerized axiography on protrusion. Side-to-side asymmetry was measured for each parameter. The asymmetry index value was calculated to assess the correlation between TMJ morphology and condylar movement. For the statistical analysis, Wilcoxon's signed-ranked test, the Mann-Whitney U test, and Spearman's rank correlation were used.

RESULTS

Glenoid fossa volume, surface area, anteroposterior length, and condylar volume were significantly smaller, and articular eminence angle, glenoid fossa, and condylar axial angle were significantly larger, on the shifted side of the MA group when compared with those on the non-shifted side and the mean values of the control group (P < 0.05). The TMJ spaces of the MA group showed no bilateral difference but were significantly narrower in the medial, superior, and anterior joint spaces when compared with the control group (P < 0.05). Condylar path length and sagittal condylar inclination were significantly asymmetrical. The asymmetry index of the condyle volume was significantly correlated with that of the condylar path length (P = 0.005). The asymmetry index of the glenoid fossa volume and the articular eminence angle were significantly correlated with that of the sagittal condylar inclination (P = 0.009 and P = 0.002, respectively), and the asymmetry index of glenoid fossa volume was significantly correlated with the bilateral transverse condylar inclination (P = 0.006 and P = 0.016, respectively).

CONCLUSIONS

Morphological asymmetry of the TMJ is significantly different between the shifted and non-shifted sides and is closely related to functional asymmetry of condylar movement in MA patients. (350/350).

Biomechanical comparative analysis of temporomandibular joint, glenoid fossa and head of the condyle of conventional models prothesis with new PEEK design

This article reviews the design of the temporomandibular joint (TMJ) prostheses used for TMJ joint replacement from 2000 to 2020. The TMJ is a complex joint, with distinct anatomical and functional characteristics making it challenging to maintain. Many authors from the early 20th century reported techniques for TMJ reconstruction, with the goal of restoring its shape and ideal function. Many prototypes have been developed in pursuit of an ideal prosthesis that adheres to the principles of biomechanics and biocompatibility, with good long-term performance and lower cost. The TMJ prosthesis is divided in two parts: the glenoid fossa and the mandibular ramus component. These two parts are fixed with metal screws in the glenoid fossa and fixed in the zygomatic arch with 4 or 5 screws. The mandibular part is fixed to the mandible ramus with 8 or 9 titanium screws. In our review, since 2000 to 2020, little has changed to improve the design and allow for natural mandible movement. From 2000 to 2006, 48 TMJ surgeries were performed using UHMWPE with this design. All patients had good results, preserving opening mouth and lateral movements. All the designs are similar in principle. The glenoid fossa, which resembles a box, limiting the rotation and translation movement. It is known that lateral movements are lost in function as the lateral pterygoid muscle is detached.

Functional outcomes after using the glenoid fossa as a fixed anchorage for the temporomandibular joint discopexy in patients with disc displacement without reduction

The aim of the present study was to evaluate the use of the glenoid fossa as an anchorage for the temporomandibular joint (TMJ) disc repositioning in patients with a disc displacement (DD) without reduction. A prospective case series study included patients with DD without reduction. According to the Wilkes staging system for the TMJ internal derangement, preoperative magnetic resonance imaging (MRI) scans and clinical examinations determine the stage of the DD. The discopexy treatment consists of combined endaural/preauricular incision on the tragus, and freeing the anteromedial displaced disc from its attachments. An intra bony hole was drilled 2 mm away from the postero-lateral lip of the glenoid fossa and perpendicular to it. The disc was securely fixed to the roof of the fossa via a Prolene 0 suture in a double-pass suture fashion. The functional assessment was based on the pain visual analogue scale (VAS) and measurements of the maximum inter-incisal opening (MIO) after 1, 6, 12, and 18 months. P values ≤ 0.05 were considered significant. Thirteen of 25 joints were diagnosed with Wilkes stage III. The mean VAS score significantly decreased to 2.2 ± 1.0 and the MIO also significantly improved with a mean of 35.9 ± 3.5 mm after 18 months (P < 0.001). The rest of the cases (12 joints) were diagnosed with Wilkes stage IV, and the VAS score decreased to 1.6 ± 0.7. The MIO increased to 34.2 ± 3.3 mm at the end of the follow-up (P < 0.001). Within the limitations of the study, it seems that using the glenoid fossa as anchorage for the TMJ disc might have some clinical relevance and therefore might be taken into consideration whenever it is deemed appropriate.

Cone-beam computed tomographic assessment of the inclination of the articular eminence in patients with temporomandibular disorders and chewing side preference

Background

Chewing side preference (CSP) has been proposed as one etiology of temporomandibular disorders (TMDs) as it can induce the structural changes of the temporomandibular joint. But its association with the inclination of the articular eminence (IAE) is unknown. This study aimed to compare IAE between patients with CSP and without CSP.

Methods

Cone-beam computed tomography images of 90 patients with TMD (mean age of 45.6 years, 69 with CSP, 21 without CSP) and 20 participants without TMD and CSP (mean age of 41.3 years) were measured to compare IAE and depth of the glenoid fossa (DGF)

Results

IAE and DGF showed a positive correlation among all the participants. Compared with the participants without TMD and CSP, the TMD patients without CSP presented a similar IAE but with a significantly higher value of DGF (p < 0.05); in contrast, the TMD patients with CSP presented a significantly greater IAE and DGF (p < 0.05). No bilateral differences in IAE and DGF were observed in all the participants. Except the male patients with CSP had a deeper fossa than did the female, no differences in IAE and DGF according to gender were observed.

Conclusions

TMD patients with CSP seem to have a deep glenoid fossa with steep eminence which might be considered one characteristic imaging feature.

A Modified Technique of Temporomandibular Joint Arthroscopic Operative Surgery of the Superior and Inferior Joint Spaces

PURPOSE

This paper describes in detail the first author's technique of performing arthroscopic surgery in both the superior and inferior joint spaces of the temporomandibular joint.

METHODS

The key is careful measurement of sagittal and coronal tomograms to determine the individual size and shape of the joint. The joint is then distracted to allow 3-port video arthroscopy.

RESULTS

The detailed steps in the procedure are described and illustrated.

CONCLUSION

This modified technique is safe and allows procedures in both joint spaces and surgical access to the fossa, condyle and disc.

Volumetric and morphological analysis of condyle and glenoid fossa on computed tomography

AIM

The aim of this study was to evaluate temporomandibular joint (TMJ) condyle and glenoid fossa morphology with measurements on Computed Tomography (CT) and volumetric analysis using InVesalius software program.

MATERIALS AND METHODS

250 condyles in 125 patients (mean age: 40.64) was evaluated on CT. Length, width, and height of the condyle, condylar volume, the thickness of glenoid fossa (TGF), condyle surface area, anterior space (AS), superior space (SS), and posterior space (PS) were measured in this study. Two left and right sides of the jaw have been measured. Linear measurements were performed with the image analysis program (Image J, 1.4 v version, National Institutes of Health, Bethesda, MD). Volume and surface area measurements were performed with InVesalius software (CTI, Campinas, SãoPaulo, Brazil).

RESULTS

To compare the dimensions of the condyle between males and females, there was only a significant difference in left AS and SS and no significant difference was found between males and females in other measured factors. There was a significant difference between the age groups and left SS. A significant difference was also found between the age groups and condylar height, condyle surface area, and condylar volume on both right and left sides.

CONCLUSION

Evaluation of condylar morphology is important to assess the TMJ anomalies and bony changes. This study showed no significant differences between gender and all measured factors except in the left AS and SS. However, age factor had a major effect on the morphology.

Evaluation of structural skeletal asymmetry of the glenoid fossa in adult patients with unilateral posterior crossbite using surface-to-surface matching on CBCT images

OBJECTIVES

To compare, using surface-to-surface (StS) matching, any shape differences between the crossbite and noncrossbite side of the glenoid fossa and articular eminence in adult patients affected by posterior unilateral crossbite (PUXB) and compare them with unaffected controls.

MATERIALS AND METHODS

32 cone beam computed tomography (CBCT) scans of patients (mean age: 23.72 ± 3.74 years) undergoing surgical maxillary expansion were analyzed to obtain three-dimensional models of the left and right glenoid fossae that were superimposed using stable anatomical reference points and then compared using StS matching to evaluate the presence of any shape differences. These findings were compared with those obtained from 16 CBCT scans of unaffected controls (mean age: 23.72 ± 3.73 years).

RESULTS

A mean difference of >11% was found between the study group and controls when comparing the matching percentages of the two sides of the glenoid fossa and articular eminence at all three levels of tolerance selected for this study. These differences were found to be highly statistically significant (P ≤ .0001).

CONCLUSIONS

According to the shape analysis findings, adult PUXB patients exhibit a higher degree of glenoid fossa and articular eminence shape differences compared to unaffected controls.

An anthropometric evaluation of the scapula, with emphasis on the coracoid process and glenoid fossa in a South African population

The exact dimensions of the scapula, including the coracoid process and glenoid fossa, are fundamental in the patho-mechanics of the glenohumeral joint (GHJ); as these structures act as initiators of shoulder movement. The aim of the study was to evaluate the anthropometric parameters of the GHJ, with emphasis on the coracoid process and glenoid fossa. The morphometric (Linear Tools 2012, 0-150mm, LIN 86500963) and morphological parameters of a total of one hundred and sixty-four (n = 164) dry bone scapulae [Right (R): 80; Left (L): 84, Male (M): 68; Female (F): 96] were recorded. Results: (i) Shape of glenoid fossa: Type 1: (R) 16.5%, (L) 11.0%; Male (M) 20.1%, Female (F) 7.3%; Type 2: (R) 14.0%, (L) 15.2%; (M) 18.3%, (F) 11.0%; Type 3: (R) 18.3%, (L) 25.0%; (M) 27.4%, (F) 15.9%. (ii) Notch type: Type 1: (R) 1.7%, (L) 7.3%; (M) 6.7%, (F) 2.4%; Type 2: (R) 47.0%, (L) 43.9%; (M) 59.2%, (F) 31.7%. (iii) Vertical diameter of glenoid fossa (VD) (mm): (R) 35.2 ± 3.1, (L) 34.9 ± 3.0; (M) 35.3 ± 3.2, (F) 34.6 ± 2.8. (iv) Horizontal diameter 1 (HD1) of glenoid fossa (mm): (R) 18.4 ± 3.3, (L) 17.5 ± 2.9; (M) 18.2 ± 3.3, (F) 17.4 ± 2.6. (v) Horizontal diameter 2 (HD2) of glenoid fossa (mm): (R) 24.5 ± 2.9, (L) 23.6 ± 2.6; (M) 24.2 ± 2.7, (F) 23.7 ± 2.8. (vi) Length of coracoid process (CL) (mm): (R) 41.7 ± 4.7, (L) 41.5 ± 4.9; (M) 42.1 ± 4.7, (F) 40.7 ± 4.8. (vii) Width of coracoid process (CW) (mm): (R) 13.3 ± 1.9, (L) 14.2 ± 11.9; (M) 13.1 ± 1.9, (F) 15.1 ± 14.5. (viii) Coracoglenoid distance (CGD) (mm): (R) 27.4 ± 8.3, (L) 28.2 ± 3.5; (M) 28.2 ± 7.4, (F) 27.0 ± 3.4. In the present study, Type 3 (oval) was observed to be the predominant glenoid fossa shape with a higher incidence in male individuals and on the right side. Although only notch Types 1 (without a notch) and 2 (with one notch) were observed in this study, Type 2 (one notch) was the most prevalent, presenting with a significant p-value (p = 0.019), suggesting that notch Type 1 (without a notch) and 2 (with one notch) are common findings in the right and left side of individuals. The findings observed in this study may provide knowledge regarding the role of the coracoid parameters in etiology of subcoracoid impingement while knowledge on the glenoid fossa parameters and variations are essential for evaluation in shoulder arthroplasty for glenoid fractures and anterior dislocations, and for glenoid prosthesis designs for the South African population.

[Shoulder prosthesis replacement options : New implants, treatment algorithms and clinical results]

BACKGROUND

Bony defect situations are a common problem in revision arthroplasty of the shoulder and are the cause of the complexity of the procedure. Aseptic and septic loosening as well as difficult implant removal can result in humeral and/or glenoid bone loss.

PLANNING

A careful preoperative imaging is needed to estimate the extent of the bony defect and to enable precise planning of the bone reconstruction and the required implants. However, the size of the defect needs to be re-evaluated intraoperatively after removal of the implant components and any larger defects have to be addressed appropriately.

PROSTHESIS DESIGN

While in the glenoid autologous bone grafts and, to a lesser extent, allogenic bone grafts are preferred, metallic augmented implants have recently become available to fill the glenoid bone defect. However, humeral defects are normally addressed with longer revision stems, possibly with allograft augmentation. The soft tissue loss in proximal humeral defects can be addressed with fixation techniques to improve function and reduce the risk of dislocation. Modern modular prosthesis designs allow prosthesis conversion while leaving bony, tightly integrated component parts on the glenoid or shaft. This review describes the preoperative diagnostic steps as well as techniques for revision surgery of the shoulder in the case of bone loss.

Prevalence of pneumatization of the articular eminence and glenoid fossa viewed on cone-beam computed tomography examinations in a Turkish sample

OBJECTIVE

The aim of this study is to evaluate the prevalence of the pneumatization of the articular eminence and glenoid fossa (PAT and PGF, respectively) using cone-beam computed tomography (CBCT).

METHODS

CBCT images of 1000 patients (511 females and 489 males) representing 2000 regions of interest (the glenoid fossa and articular eminence of each patient) were examined retrospectively with regard to age, gender, laterality, and type of pneumatization. The mean age of the female patients was 39.66 and that of males was 39.79. Suitable images from patients aged 16 years and over found in the archives of CBCT images were included in the study. The data were assessed using IBM SPSS 20 and statistical comparisons between two categorical variables were conducted using Chi square tests.

RESULTS

It was observed that 14.7% of the patients had PAT and 47.1% had PGF. There was no significant difference in PAT and PGF prevalence between ages, age ranges, and gender in our study (p > 0.5).

CONCLUSIONS

It is important to evaluate the pneumatic cells in the articular eminence and glenoid fossa regions before surgery. It was also found that CBCT is more helpful in detecting pneumatization than plain film.

Comparison of temporomandibular joint shape and size in patients with facial asymmetry

OBJECTIVE

To examine the morphologic similarities and differences in mandibular condyle and glenoid fossa between the deviated and non-deviated sides in patients with facial asymmetry using statistical analysis.

METHODS

One hundred eighty-four patients (95 men, 89 women; mean age, 22.30 ± 3.87 years) with facial asymmetry were examined with cone-beam computed tomography (CBCT). Shape analysis was performed to compare the shapes and sizes of the condyle and fossa between the deviated and non-deviated sides in the frontal and lateral aspects. Ordinary Procrustes analysis (OPA) was used to determine shape variations of the fossa and condyle.

RESULTS

Shape variations derived from ordinary sum of squares (OSS) suggested that, in the frontal aspect, there was a difference between the two sides in both the fossa and condyle (P < 0.05). In the lateral aspect, there was no difference in fossa shape between the two sides (P > 0.05); however, the shape of condyle was different between the non-deviated and deviated sides (P < 0.05). Size comparison in OPA matching and centroid size (CS) in the frontal aspect demonstrated that the non-deviated side was larger than the deviated side. In the lateral aspect, fossa showed no difference in CS between the two sides (P > 0.05); however, the non-deviated side was larger than the deviated side for condyle (P < 0.05).

CONCLUSIONS

Morphometric differences in condyle and fossa between the deviated and non-deviated sides were observed. Structures of the non-deviated side were relatively larger than those of the deviated side, except for fossa in the lateral aspect.

Prevalence and characteristics of pneumatizations of the articular eminence and roof of the glenoid fossa on cone-beam computed tomography

OBJECTIVE

The aim of this study was to determine the prevalence and characteristics of pneumatization of the articular tubercle (PAT) and pneumatization of the roof of the glenoid fossa (PRGF) in a large population using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

This study was designed to evaluate the CBCT images of 1000 patients. The prevalences of the pneumatizations by age, sex, locularity, and laterality were determined. The significance of differences between variables was evaluated by the Chi-square test and analysis of variance.

RESULTS

PAT was detected in 28.4% of the zygomatic bone sides and PRGF in 29.6%. Bilateral PAT was detected in 176 (17.6%) patients and bilateral PRGF in 195 (19.5%). The mean age of patients with PAT was 47.33 years and that of patients with PRGF was 45.62 years. Multilocular appearance was observed significantly more often than unilocular type for both pneumatizations (p < 0.01). Unilateral PAT cases were slightly, but significantly, higher than bilateral PAT cases (p = 0.047), while no significant difference was observed between unilateral and bilateral PRGF cases.

CONCLUSIONS

In conclusion, PAT and PRGF can be assessed more accurately on CBCT images than on plain radiographs. During routine radiological investigations, maxillofacial radiologists should be aware of zygomatic air cells.

Bare spot and tubercle of Assaki

Background

The definition of the bare spot and tubercle of Assaki is controversial, with studies reporting different incidences, locations, and clinical significance. The aims of this study were to evaluate the incidence of the bare spot, to determine the length and width of the bare spot, and to assess the relationship between the bare spot and tubercle of Assaki.

Materials and methods

A total of 140 shoulders from 30 men and 40 women were dissected and examined. After exposure of the glenoid fossa with the glenoid labrum attached, direct measurement of the length and width of the bare spot was undertaken using digital calipers. The repeatability and reliability of the measurements was assessed using Kruskal-Wallis one way analysis of variance on ranks, with statistical significance set at P < .05.

Results

A bare spot was observed in 80.7% (n = 113) of shoulders, being more common in men than in women, with an overall mean length and width of 7.2 mm and 6.2 mm. It was significantly longer (P = .002) and wider (P = .018) in men.

Conclusion

A bare spot exists within the glenoid fossa and differs from the tubercle of Assaki. It is a characteristic round to oval lesion in the central or eccentric cartilage. It should not be misdiagnosed as a pathologic lesion.

A cephalometric evaluation of the effect of glenoid fossa location on craniofacial morphology

AIM

The purpose of this study was to assess the effect of glenoid fossa location in various skeletal malocclusions on craniofacial morphology.

METHODS

Cephalometric data of 84 subjects were analyzed for four linear and two angular variables for assessing glenoid fossa location in cranial base and eight linear and eight angular variables for evaluating the corresponding effect on craniofacial morphology using statistical software STATA 12 for windows. Regression analysis was done to see the effect of glenoid fossa location on the parameters measuring craniofacial morphology.

RESULTS

Significant association between glenoid fossa location and craniofacial morphology was demonstrated in skeletal class I, class II, and class III malocclusion subjects by the regression analysis.

CONCLUSIONS

Glenoid fossa location varies significantly among skeletal malocclusions and glenoid fossa location has a profound effect on craniofacial morphology of skeletal class I, class II, and class III malocclusions.

Pathoanatomy and computed tomography classification of glenoid fossa fractures based on ninety patients

PURPOSE

The aim of the article is to present the pathoanatomy and a new classification of glenoid fractures developed on the basis of analysis of 3D computed tomography (CT) examinations and intra-operative findings.

MATERIALS AND METHODS

The study group comprised 90 patients (69 men and 21 women) who sustained glenoid fractures. Mean patient age was 47 years (17-92). In 77 nonpolytraumatised patients, anteroposterior (AP) radiographs of the affected shoulder girdle were taken, including Neer I and II views. All 90 patients underwent CT examination, combined in 73 of them with 3D CT reconstruction including subtraction of the humeral head, ribs and clavicle, from the anterior and posterolateral views. In total, 52 patients (58 %) were operated on and 38 42 %) were treated non-operatively.

RESULTS

In total, five basic types of injuries to the glenoid were identified based on analysis of the separated portion of the glenoid fossa: including fractures of the superior glenoid (14 cases, 16 %), the anterior glenoid (23 cases, 23 %), the posterior rim of the glenoid (5 cases, 6 %), the inferior glenoid (38 cases, 42 %) and the entire glenoid (10 cases, 11 %).

CONCLUSION

The proposed classification of glenoid fractures defines five basic types of fractures verified by 3D CT reconstructions and intra-operative findings. It respects the anatomical architecture of scapula, fracture mechanism, associated injuries to the shoulder girdle and, where appropriate, the preferred surgical approach.

Augmented Indian hedgehog signaling in cranial neural crest cells leads to craniofacial abnormalities and dysplastic temporomandibular joint in mice

Extensive studies have pinpointed the crucial role of Indian hedgehog (Ihh) signaling in the development of the appendicular skeleton and the essential function of Ihh in the formation of the temporomandibular joint (TMJ). In this study, we have investigated the effect of augmented Ihh signaling in TMJ development. We took a transgenic gain-of-function approach by overexpressing Ihh in the cranial neural crest (CNC) cells using a conditional Ihh transgenic allele and the Wnt1-Cre allele. We found that Wnt1-Cre-mediated tissue-specific overexpression of Ihh in the CNC lineage caused severe craniofacial abnormalities, including cleft lip/palate, encephalocele, anophthalmos, micrognathia, and defective TMJ development. In the mutant TMJ, the glenoid fossa was completely absent, whereas the condyle and the articular disc appeared relatively normal with slightly delayed chondrocyte differentiation. Our findings thus demonstrate that augmented Ihh signaling is detrimental to craniofacial development, and that finely tuned Ihh signaling is critical for TMJ formation. Our results also provide additional evidence that the development of the condyle and articular disc is independent of the glenoid fossa.

[Zygomatic arch fracture extended to the glenoid fossa: a cause of TMJ pain]

INTRODUCTION

Fractures of the zygomatic arch extended to the glenoid fossa are rare and seldom reported.

OBSERVATION

A 26-year-old man with a slightly dislocated fracture of the zygoma associated with trismus, and localized pain in the right Temporo-Mandibular Joint (TMJ) on palpation, but without any condylar fracture. The craniofacial CT scan revealed a fracture of the zygoma extended to the glenoid fossa. The treatment was an intraoral reduction of the zygoma and screw fixation of the glenoid fossa lateral region.

DISCUSSION

The risk of delayed healing by mobilization of the bone fragments was opposed to the risk of TMJ ankylosis due to a prolonged immobilization of the joint. Osteosynthesis of the fracture was finally chosen.