Inclination Measurements Research Articles

Micromachined piezoresistive inclinometer with oscillator-based integrated interface circuit and temperature readout

In this paper a dual-chip system for inclination measurement is presented. It consists of a MEMS (microelectromechanical system) piezoresistive accelerometer manufactured in silicon bulk micromachining and a CMOS (complementary metal oxide semiconductor) ASIC (application specific integrated circuit) interface designed for resistive-bridge sensors. The sensor is composed of a seismic mass symmetrically suspended by means of four flexure beams that integrate two piezoresistors each to detect the applied static acceleration, which is related to inclination with respect to the gravity vector. The ASIC interface is based on a relaxation oscillator where the frequency and the duty cycle of a rectangular-wave output signal are related to the fractional bridge imbalance and the overall bridge resistance of the sensor, respectively. The latter is a function of temperature; therefore the sensing element itself can be advantageously used to derive information for its own thermal compensation. DC current excitation of the sensor makes the configuration unaffected by wire resistances and parasitic capacitances. Therefore, a modular system results where the sensor can be placed remotely from the electronics without suffering accuracy degradation. The inclination measurement system has been characterized as a function of the applied inclination angle at different temperatures. At room temperature, the experimental sensitivity of the system results in about 148 Hz/g, which corresponds to an angular sensitivity around zero inclination angle of about 2.58 Hz deg−1. This is in agreement with finite element method simulations. The measured output fluctuations at constant temperature determine an equivalent resolution of about 0.1° at midrange. In the temperature range of 25–65 °C the system sensitivity decreases by about 10%, which is less than the variation due to the microsensor alone thanks to thermal compensation provided by the current excitation of the bridge and the positive temperature coefficient of resistance of the piezoresistors.

Assessment of inter- and intra-observer reliability in the determination of radiographic version and inclination of the cup in metal-on-metal hip resurfacing

Determination of the cup orientation after metal-on-metal hip resurfacing may provide important information in the postoperative follow-up. We present a mathematical method based on a previously described approach to assess the version and inclination of the cup in the metal-on-metal bearing without a separate software computation from plain radiographs. The aim of the study was to assess the intra- and inter-observer reliability of this method. Calculation of version and inclination were done twice for 20 hip resurfacings by four observers. Intra-observer reliability was estimated by mean error and correlation of the two sets of measurement for version and inclination. Bland-Altman plots, intra-class coefficient and mean error were used to assess the inter-observer reliability of the measurements. Intra-observer correlation for version measurement ranged from 0.74 to 0.94. Correlation for inclination varied between 0.94 and 0.97. Upper and lower limits of agreement in Bland-Altman plots for version measurements between observers ranged from 4.1 to 7.2 degrees and from -3.2 to -8.3 degrees, respectively. For inclination measurements the upper and lower limits ranged from 3.1 to 5.3 degrees and from -2.7 to -6.0 degrees. Mean errors, correlation coefficients and 95% limits of agreement were on an acceptable level. We believe that this method is applicable for clinical use.

Morphologic Evaluation and Classification of Facial Asymmetry Using 3-Dimensional Computed Tomography

A systematic classification is needed for the diagnosis and surgical treatment of facial asymmetry. The purposes of this study were to analyze the skeletal structures of patients with facial asymmetry and to objectively classify these patients into groups according to these structural characteristics. Patients with facial asymmetry and recent computed tomographic images from 2005 through 2009 were included in this study, which was approved by the institutional review board. Linear measurements, angles, and reference planes on 3-dimensional computed tomograms were obtained, including maxillary (upper midline deviation, maxilla canting, and arch form discrepancy) and mandibular (menton deviation, gonion to midsagittal plane, ramus height, and frontal ramus inclination) measurements. All measurements were analyzed using paired t tests with Bonferroni correction followed by K-means cluster analysis using SPSS 13.0 to determine an objective classification of facial asymmetry in the enrolled patients. Kruskal-Wallis test was performed to verify differences among clustered groups. P < .05 was considered statistically significant. Forty-three patients (18 male, 25 female) were included in the study. They were classified into 4 groups based on cluster analysis. Their mean age was 24.3 ± 4.4 years. Group 1 included subjects (44% of patients) with asymmetry caused by a shift or lateralization of the mandibular body. Group 2 included subjects (39%) with a significant difference between the left and right ramus height with menton deviation to the short side. Group 3 included subjects (12%) with atypical asymmetry, including deviation of the menton to the short side, prominence of the angle/gonion on the larger side, and reverse maxillary canting. Group 4 included subjects (5%) with severe maxillary canting, ramus height differences, and menton deviation to the short side. In this study, patients with asymmetry were classified into 4 statistically distinct groups according to their anatomic features. This diagnostic classification method will assist in treatment planning for patients with facial asymmetry and may be used to explore the etiology of these variants of facial asymmetry.

Discovery of pulsar planets

In this paper I recount the events which have led to the discovery of the first planets beyond the Solar System. The two planets circling an old neutron star, the 6.2ms pulsar PSR B1257+12, were discovered in 1991 with the 1000ft Arecibo radio telescope. The pulsar itself was detected by a large, all-sky survey conducted during the telescope maintenance period in early 1990. The subsequent timing observations have shown that the only plausible explanation of the variability of pulse arrival times of PSR B1257+12 was the existence of at least two terrestrial-mass planets around it. The third, Moon-mass planet in the system was detected in 1994, along with the measurement of perturbations resulting from a near 3:2 mean motion resonance between the two more massive bodies, which has provided the confirmation of a planetary origin of the observed variations of pulse arrival times. Further observations and analyses have resulted in an unambiguous measurement of orbital inclinations and masses of the planets in 2003. The measured approximate coplanarity of the orbits along with the inner solar system – like dynamical properties of the pulsar planets strongly suggest their origin in a protoplanetary disk, just like in the case of planets around normal stars. The existence of such a system predicts that rocky, Earth-mass planets should be common around various kinds of stars.

FIXATION OF FRACTURES OF THE DISTAL EXTREMITY OF THE RADIUS USING THE MODIFIED KAPANDJI TECHNIQUE: EVALUATION OF THE RADIOLOGICAL RESULTS

To demonstrate a simple and efficacious option for treating fractures of the distal extremity of the radius using Kirschner wires. Methods: Between September 2008 and April 2009, 48 patients with fractures of the distal extremity of the radius, classified as A3 according to the AO classification, were treated surgically using a modification of the Kapandji technique. Results: Out of the 48 wrists operated, 42 (87.5%) presented postoperative measurements within the acceptable limits. We used the parameters of McQuenn and Caspers who considered that the radial angulation should be wider than 19° and the volar angulation should be narrower than -12°. All the postoperative volar inclination measurements were narrower than -3°. The mean preoperative radial inclination was 13.14° and the mean postoperative value was 21.18°. The mean preoperative volar inclination was 28.75° and the mean postoperative value was 3.31°. The mean preoperative radial height was 5.25 mm and the mean postoperative value was 9.48 mm. Conclusion: The technique described here had excellent stability for treating fractures of the distal extremity of the radius classified as A3. It was easy to implement and minimally invasive, with minimal surgical complications, and it was inexpensive.

Distal Radius Fractures Using Acu-Loc Volar Plate

Objective: We determined the radiographic outcome of distal radius fractures with Acu-loc volar plate. Methods: Forty-one patients were recruited between August 2009 and September 2010. There were 10 males and 31 females, with a mean age 61.2. Fractures were radiologically classification the Frykman. Fifteen fractures were group 8, eight were group 7, ten were group 6, four were group 5 and four were group 3. Distal part of the fractures was dorsally inclined in 37 wrists and inclined to volar side in four wrists. Lateral and anteroposterior radiographs taken after operated day, the fracture were compared with radiographs of the injured wrist and the differences in palmar tilt, ulnar variance; radial height; radial shift and radial inclination were measured. Results: There was significant improvement in the measurements of radial height, radial inclination, volar tilt, ulnar variance and radial shift postoperatively. The radial height improved from an average of 8.5 mm (range, 3 to15 mm) to 11.0 mm (range, 8 to15 mm), the radial inclination improved from an average of 21.5 degree (range, 10 to 40 degree) to 28.1 degree (range, 19 to 44 degree), the palma tilt improved from an average of 12.9 degree (range, 6 to 22 degree) to 17.2 degree (range, 7 to 27 degree), the ulnar variance improved from an average of -2.3 mm (range, -6 to 4 mm) to 1 mm (range, -3 to 7 mm) and the radial shift improved from an average of 18.7 mm (range, 15 to 26 mm) to 17.3 mm (range, 12 to 21 mm). Conclusion: Acu-loc volar plate is a safe and effective device.

A re-evaluation of the Italian historical geomagnetic catalogue: implications for paleomagnetic dating at active Italian volcanoes

Abstract. Paleomagnetism is proving to represent one of the most powerful dating tools of volcanics emplaced in Italy during the last few centuries/millennia. This method requires that valuable proxies of the local geomagnetic field (paleo)secular variation ((P)SV) are available. To this end, we re-evaluate the whole Italian geomagnetic directional dataset, consisting of 833 and 696 declination and inclination measurements, respectively, carried out since 1640 AD at several localities. All directions were relocated via the virtual geomagnetic pole method to Stromboli (38.8° N, 15.2° E), the rough centre of the active Italian volcanoes. For declination-only measurements, missing inclinations were derived (always by pole method) by French data (for period 1670–1789), and by nearby Italian sites/years (for periods 1640–1657 and 1790–1962). Using post-1825 declination values, we obtain a 0.46 ± 0.19° yr−1 westward drift of the geomagnetic field for Italy. The original observation years were modified, considering such drift value, to derive at a drift-corrected relocated dataset. Both datasets were found to be in substantial agreement with directions derived from the field models by Jackson et al. (2000) and Pavon-Carrasco et al. (2009). However, the drift-corrected dataset minimizes the differences between the Italian data and both field models, and eliminates a persistent 1.6° shift of 1933–1962 declination values from Castellaccio with respect to other nearly coeval Italian data. The relocated datasets were used to calculate two post-1640 Italian SV curves, with mean directions calculated every 30 and 10 years before and after 1790, respectively. The curve comparison suggests that both available field models yield the best available SV curve to perform paleomagnetic dating of 1600–1800 AD Italian volcanics, while the Italian drift-corrected curve is probably preferable for the 19th century. For the 20th century, the global model by Jackson et al. (2000) yields more accurate inclination values, while the declinations from our drift-corrected curve seem to better represent the local field evolution, at least for the first half of the century.

Manual and Computerized Measurement of Sagittal Vertebral Inclination in Computed Tomography Images

Sagittal vertebral inclination (SVI) was systematically evaluated in computed tomography (CT) images by three observers using six manuals and two computerized measurements. To analyze and compare manual and computerized measurements of SVI in CT images. A number of methods were proposed to measure SVI in lateral radiographic projections in the form of spinal curvature or segmental angulation. A systematic analysis of the manual and computerized measurements in sagittal CT cross-sections has not been performed yet. SVI was measured in CT images for 28 vertebrae independently by three observers. Manual measurements were obtained in sagittal cross-sections by manually identifying the vertebral body corners, which defined the lines of SVI (superior and inferior tangents, anterior and posterior tangents, mid-endplate and mid-wall lines) against reference horizontal or vertical lines. Computerized measurements were obtained by manually identifying the vertebral centroids, which initialized the automated method that evaluated SVI by searching for the planes of maximal symmetry of vertebral bodies in two dimensions and in three dimensions. The midwall lines proved to be the most reproducible and reliable manual measurements (1.0° and 1.4° standard deviations [SD]). The computerized measurements in three dimensions were more reproducible and reliable (0.9° and 1.3° SD) and also most consistent with the midwall lines (2.1° SD and 1.7° mean absolute difference). The manual measurements based on mid-wall lines and the computerized measurements in three dimensions yielded the lowest intraobserver and interobserver variability of SVI. However, in terms of speed and operator friendliness, the computerized measurements may represent an adequate alternative to manual measurements.

Estimating leaf inclination and G-function from leveled digital camera photography in broadleaf canopies

The effectiveness of using leveled digital camera for measuring leaf inclination angles was investigated in this study as an inexpensive and convenient alternative to existing approaches. The new method is validated with manual leaf angle measurements for various broadleaf tree species common to hemi-boreal region of Estonia and the tropical forests of Hawai’i Islands. The acquired leaf angle distributions suggest that planophile case might be more appropriate than the commonly assumed spherical as the general approximation of leaf orientation while modeling the radiation transmission through the canopies of (hemi)-boreal broadleaf stands. However, direct leaf inclination measurements should be obtained whenever possible, as there will always exist a large variety of leaf orientation, both among different species and in the space–time domain within a single species. The camera method tested in this study provides a new robust and affordable tool to obtain this information.

Konventionelle Hüftpfannennavigation mit dem Röntgenbildwandler: Korrekte Positionierung der Hüftpfanne unter Berücksichtigung des Pelvic Tilts

The objective of this study was to asses the accuracy of conventional cup navigation with 2D-fluoroscopy compared to free-hand positioning in total hip arthroplasty. A test of the procedure in a plastic bone model of the pelvis was undertaken: the implantation of 28 cups respecting the individual pelvic tilt was evaluated. The intraoperative determination of a reference plane for navigation by fluoroscopic matching of the anterior pelvic ring with the pre-operative X-ray of the pelvis was performed. The target zone was a radiological inclination 40 ± 10° and a radiological anteversion 15 ± 10°. Measurement of cup position was done with 3D-CT respecting the pelvic tilt and additionally with conventional X-ray images. CLINICAL APPLICATION IN PATIENTS: A comparison was made of 80 consecutive, in 2008 operated patients (navigation group) with 80 consecutive in 2006 operated patients (free-hand group). Measurement of cup position in both groups was made with conventional X-ray of the pelvis (mean value and standard deviation of radiological inclination and anteversion, the number of outliers of the target zone in navigation group and free-hand group). In plastic bone models all cups were positioned in the target zone. Measurement of radiological inclination and anteversion with 3D-CT and X-ray demonstrated a good concordance (mean difference CT versus X-ray for inclination 0.625°, max. 2°, for anteversion 0.75°, max. 3°). In patients, conventional cup navigation was significantly superior to free-hand positioning in anteversion (SD 2.9° nav, SD 8.1° free, outliers of target zone: n = 2 nav, n = 18 free). No significant differences were detected in inclination. The coronal plane of the patient was found to be a valid plane for cup navigation that can be determined by intraoperative fluoroscopy. The method allows for a safe positioning of the cup in the target zone for inclination and anteversion. Conventional cup navigation with 2D-fluoroscopy is simple and safe with limited investment in time, manpower and material.

Determination of small in-plane angular displacement in machine tool alignment using two matched moiré fringes

Small in-plane angular displacement is determined by adopting two matched moiré fringes and frequency analysis method in this paper. The gratings in the specimen and reference have a complementary configuration; when the specimen has an angular displacement with respect to the reference, two matched moiré fringes rotate in opposite directions, and thus this angle determination method does not depend on the direction of the moiré fringe in a charge-coupled device (CCD) camera. The frequency components acquired by fast Fourier transfer and local frequency spectrum zooming process are used to determine the fringe inclination. Different from the two-dimensional fast Fourier transform (FFT) method, this method can realize the accurate measurement of fringe inclination in any direction by selecting different orthogonal frequency components. After the magnitude of fringe inclination is determined, automatic detection of fringe orientation is realized by comparing the peak frequencies in their possible directions. This method can be used to determine the angular displacement automatically and accurately.

Herbst treatment with mandibular cast splints—revisited

The objective of this study was to reassess the dento-skeletal treatment effects and the amount of anchorage loss during reduced mandibular splint (RMS) Herbst treatment. One hundred consecutive Class II patients treated with a RMS-Herbst appliance were analyzed. The mean pretreatment age of the patients was 14.5 years, and the mean treatment time with the Herbst appliance was 8.1 months. Both before (T1) and after (T2) Herbst treatment a cephalometric measurement of lower incisor inclination, a sagittal occlusion analysis, and a dental cast analysis were performed. A comparison was performed with a historic Herbst control group treated with total mandibular cast splints (TMS). During treatment the lower incisors proclined markedly (12.9° ± 4.6°). The amount of incisor proclination in the RMS group was, on average, 3.6° larger (P < .001) than in the TMS group. The lower incisor proclination increased from 11.9° (prepeak) to 14.3° (young adult). The level of professional experience of the practitioners performing the treatment did not influence the amount of incisor proclination significantly. The total available space in the lower arch increased by an average of 1.8 mm, and a space opened between the lower second premolars and lower permanent first molars in 62% of the present RMS-Herbst (average of 0.4 mm per side). Treatment with RMS-Herbst appliances leads to higher proclination of the lower incisors than does treatment with TMS-Herbst appliances; it also leads to an overall larger amount of anchorage loss.

The psychometric properties and utility of the Short Sadistic Impulse Scale (SSIS).

Sadistic personality disorder (SPD) has been underresearched and often misunderstood in forensic settings. Furthermore, personality disorders in general are the subject of much controversy in terms of their classification (i.e., whether they should be categorical or dimensional). The Sadistic Attitudes and Behaviors Scale (SABS; Davies & Hand, 2003; O'Meara, Davies, & Barnes-Holmes, 2004) is a recently developed scale for measuring sadistic inclinations. Derived from this is the Short Sadistic Impulse Scale (SSIS), which has proved to be a strong unidimensional measure of sadistic inclination. Through cumulative scaling, it was investigated whether the SSIS could measure sadism on a continuum of interest, thus providing a dimensional view of the construct. Further, the SSIS was administered along with a number of other measures related to sadism in order to assess the validity of the scale. Results showed that the SSIS has strong construct and discriminant validity and may be useful as a screening measure for sadistic impulse.

Georg Neumayer’s magnetic survey of the colony of Victoria 1858–1864

From 1858 to 1864 Georg Neumayer supervised and personally observed measurements of magnetic declination, inclination and intensity at the Flagstaff Hill and the new Melbourne observatories. During this time he also travelled extensively to make regional observations at over 230 locations throughout the colony. The setting up and the layout of his instruments in the observatories, the measurements made and a brief summary of the published results is included here as are accounts of each of Neumayer’s trips, some of which were to remote regions and at times made in hazardous conditions. Neumayer’s travelling companions are identified and specific incidents are highlighted. His innovative study of the Cranbourne meteorite is discussed along with his mentions of the magnetic responses of geological structures he had seen in his travels. Neumayer’s regional magnetic results and his published magnetic maps are then summarised and placed into context with work by others.

Cross-Sectional analysis of levels and patterns of objectively measured sedentary time in adolescent females

BackgroundAdolescent females have been highlighted as a particularly sedentary population and the possible negative effects of a sedentary lifestyle are being uncovered. However, much of the past sedentary research is based on self-report or uses indirect methods to quantity sedentary time. Total time spent sedentary and the possible intricate sedentary patterns of adolescent females have not been described using objective and direct measure of body inclination. The objectives of this article are to examine the sedentary levels and patterns of a group of adolescent females using the ActivPAL™ and to highlight possible differences in sedentary levels and patterns across the week and within the school day. A full methodological description of how the data was analyzed is also presented.MethodsOne hundred and eleven adolescent females, age 15-18 yrs, were recruited from urban and rural areas in the Republic of Ireland. Participants wore an ActivPAL physical activity monitor for a 7.5 day period. The ActivPAL directly reports total time spent sitting/lying every 15 seconds and accumulation (frequency and duration) of sedentary activity was examined using a customized MATLAB® computer software programme.ResultsWhile no significant difference was found in the total time spent sitting/lying over the full 24 hour day between weekday and weekend day (18.8 vs. 18.9 hours; p = .911), significantly more sedentary bouts of 1 to 5 minutes and 21 to 40 minutes in duration were accumulated on weekdays compared to weekend days (p < .001). The mean length of each sedentary bout was also longer (9.8 vs. 8.8 minutes; p < .001). When school hours (9 am-3 pm) and after school hours (4 pm-10 pm) were compared, there was no difference in total time spent sedentary (3.9 hours; p = .796) but the pattern of accumulation of the sedentary time differed. There were a greater number of bouts of > 20 minutes duration during school hours than after school hours (4.7 vs. 3.5 bouts; p < .001) while after school time consisted of shorter bouts < 20 minutes.ConclusionsSchool is highlighted as a particularly sedentary setting for adolescent females. Interventions to decrease sedentary time at school and the use of wearable devices which distinguish posture should be encouraged when examining sedentary patterns and behaviors in this population.

The development of inclination measurement by using the imaging based autofocus method

The path scanning methods frequently use in the large area inspection. The inspection accuracy is easy affected by the inclination of the inspection target when the inspection area is too large (length>100mm). It will result to the defocus of captured image and enlarge the inspection results. In conventional, the additional sensor or focus associated device is used to maintain the focus status of lens during the inspection or measurement. In usually, the additional devices are expensive and it doesn’t suit each application. In this paper, the imaging base autofocus method was used to measure the 2 dimensional inclinations. And this paper presents a numerical method to compensate the scanning path. It can decrease the defocus status during scanning or measurement. The presented method based on the existed 3 axis optical inspection system, it didn’t need additional device or component. It will improve the inspection accuracy and doesn’t increase the system cost.

Fixação das fraturas da extremidade distal do rádio pela técnica de kapandji modificada: avaliação dos resultados radiológicos

OBJETIVO: Demonstrar uma opção simples e eficaz para o tratamento das fraturas da extremidade distal do rádio com o uso de fios de Kirschner. MÉTODOS: No período de setembro de 2008 a abril de 2009, foram tratados, cirurgicamente, 48 pacientes com fraturas da extremidade distal do rádio classificadas como A3 pela classificação AO, usando uma modificação da técnica de Kapandji. RESULTADOS: Dos 48 punhos operados, 42 (87,5%) apresentaram mensurações pós-operatórias dentro dos limites considerados adequados. Utilizamos os parâmetros de McQuenn e Caspers, que consideram uma angulação radial maior que 19º e uma angulação volar menor que -12º. Todas as medidas de inclinação volar do rádio pós-operatórias estiveram abaixo de -3º. O valor da inclinação radial pré-operatória média era de 13,14º e a medida pós-operatória foi de 21,18º. O valor médio da inclinação volar pré-operatória era 28,75º e a mensuração da inclinação volar pós-operatória era 3,31º. A média da altura radial pré-operatória era 5,25mm e a medida pós-operatória foi 9,48mm. CONCLUSÃO: A técnica descrita tem excelente estabilidade para o tratamento das fraturas da extremidade distal do rádio classificadas como A3, é de fácil execução, minimamente invasiva, com mínimas complicações cirúrgicas e é de baixo custo.

Precipitation measurement and derivation of precipitation inclination in a windy mountainous area in northern Costa Rica

AbstractOver small‐scale topography in windy areas, precipitation tends to be redistributed by wind through the modification of precipitation inclination. The latter is often derived from wind speed and conventional rain gauge records by application of relations—derived mainly for convective rainfall conditions—between (1) precipitation intensity and drop diameter, and (2) drop diameter and terminal fall velocity. However, it remains to be seen whether such relationships give valid results for the typically low precipitation intensities prevailing in tropical montane cloud forests. On the basis of the assumption that the total amount of near‐surface atmospheric liquid water, defined hereafter as the ‘potential precipitation’, is most likely to be identical over small distances, this paper introduces a device to measure amounts of potential precipitation. The gauge captures both the vertical and horizontal component of precipitation, and this allows derivation of precipitation inclination using simple trigonometry. Results on precipitation inclinations obtained with the ‘potential precipitation gauge’ on a wet and windy site in northern Costa Rica suggest the droplets to be smaller than those predicted by the commonly used relationships referred to above. The current gauge is also shown to be more effective in catching inclined precipitation than two different types of spherical gauges. In addition, ‘effective’ fall velocities were determined for each precipitation event using derivated precipitation inclination and wind speed. The assumption of spatially similar potential precipitation amounts and effective fall velocities throughout a small catchment allows the catchment‐wide determination of precipitation inclination and therefore of hydrologically effective precipitation from a single‐point measurement of potential precipitation and wind speed in combination with modelled spatial wind speed pattern. This approach is believed to yield appreciably better estimates of spatial precipitation inputs compared to reliance on conventional rain gauges and derivation of terminal fall velocities from precipitation intensity records. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Picture archiving and communications systems: a study of reliability of orthodontic cephalometric analysis

The objectives of this study were to investigate the possibility of using a picture archiving and communications system (PACS) for basic chairside cephalometric analysis and to compare PACS with hand-tracing and on-screen digitization using a commercial program (Dolphin Imaging Plus Version 10.0). One hundred digital lateral cephalometric radiographs were selected and analysed using the Eastman analysis. Angular and linear measurements were recorded and a single operator traced each radiograph twice, using each of the following methods: PACS, hand-tracing, and Dolphin Imaging. The British Standards Institution Coefficient of Repeatability was used to investigate repeatability within each method and the Bland and Altman method to investigate systematic and random errors between methods. The PACS was more repeatable than Dolphin for measuring the angle between the upper incisors and the maxillary plane but was less repeatable than hand-tracing for measuring percentage lower anterior face height (LAFH). There were statistically significant systematic differences between PACS, hand-tracing, and Dolphin for measurement of lower incisor inclination. However, all three methods agreed, on average, and differences between methods were all within clinically acceptable limits. PACS was found to be clinically acceptable to be used chairside, without the need for hand-tracing or involvement of any orthodontic software. This offers the freedom to analyse digital cephalograms within a clinical area at the same appointment as when the digital radiograph is taken.

Glenoid spherical orientation and version

Glenoid orientation likely plays an important role in shoulder mechanics and has been associated with glenohumeral instability, rotator cuff tears, and total shoulder arthroplasty outcome. Glenoid version and inclination measurements are widely used, but these measurements are 2-dimensional, and orientation of the central face must be inferred from 2 points on the outer rim. This study tested the hypothesis that sphere fitting provides an optimal assessment of glenoid face 3-dimensional orientation, and clinically important differences will exist in some individuals between sphere fit orientation and traditional version measurement. Computed tomography scans of 20 normal glenoids were obtained. Glenoid version was measured from resliced, pure transverse images at a series of glenoid heights. Separately, the 3-dimensional surface of each glenoid face was reconstructed. A sphere was fit to the glenoid face, and its orientation was described by 2 angles analogous to version and inclination. "Sphere fit version" averaged -3.2° ± 3.4° (negative indicating retroversion), and "sphere fit inclination" averaged 1.3° ± 4.7°. Absolute differences between sphere fit version and the standard mid-glenoid version averaged 1.5° (maximum 4.0°) across patients. The glenoids were, on average, 5.5° more retroverted at the 80% height than at the 20% height. Three-dimensional aspects of the glenoid, including the spiraling twist evidenced by increased retroversion superiorly, are accounted for in this novel sphere-fitting approach for assessing glenoid orientation. For most normal glenoids, midglenoid version appears to provide an adequate measure of glenoid central face orientation. Sphere fitting has potential utility in optimizing glenoid implant alignment in total shoulder arthroplasty.