Auricular Surface Research Articles

Transitional Female Sacrum: Dimensions, Alterations in Dorsal Pelvic Structure, and Potential Obstetric Implications.

The space available within the female pelvis is determined by the morphology of all bony components constituting the pelvic skeleton. Although several studies have investigated the impact of hip-bone structural variations in on parturition, the potential effects of commonly occurring lumbosacral transitional vertebrae (LSTV) variations have been underreported. This descriptive morphometric study reports dimensions of the female sacrum associated LSTV variations and suggests their probable mechanistic effects on normal labor. One hundred and twelve female osteological sacral specimens with LSTV were examined for the type of transitional anomaly. Position, height, and surface areas of the auricular surfaces, interauricular distances, sacral heights, S1 body width and upper surface areas, and articulating areas of S1 facets were measured and compared with data from non-transitional samples. Female LSTV predominantly presented as accessory L5-S1 articulations (unilateral and bilateral) and degrees of lumbarization (separation of the first sacral segment). Since some of these alterations were found to be significantly associated with changes in sacral size, these features, in conjunction with cranial shift of the auricular surfaces, may be associated with overall in dorsal pelvic dimensions. Structural alterations identified in female LSTV sacrum may change dorsal pelvic dimensions and thus, the availability of dorsal pelvic space, potentially altering the biomechanics of normal labor.

Three-dimensional morphological analysis of the human sacroiliac joint: influences on the degenerative changes of the auricular surfaces.

The sacroiliac joint (SIJ) is responsible for weight transmission between the spine and lower extremity. However, details of the structure and function of the SIJ remain unclear. In a previous study, we devised a method of quantitatively evaluating the level of degeneration of the SIJ using an age estimation procedure for the auricular surface of the ilium. Our results in that study suggested that the degree of degeneration of the joint surface may be associated with the morphology of the auricular surface of the ilium. In that study, however, the morphology of the auricular surface of the ilium was simplified for analysis, meaning that more detailed investigations were required in future. In the present study, we focused on individual differences in the shape of SIJ and carried out three-dimensional quantitative evaluation of the morphology of the auricular surface of the ilium to ascertain its association with joint degeneration. We produced three-dimensional images of the right auricular surfaces of the ilium of 100 modern Japanese men (age 19-83), and obtained the three-dimensional rectangular coordinates of 11 defined measurement points. We then calculated 16 parameters indicating the morphological characteristics of the auricular surfaces of the ilium from the three-dimensional rectangular coordinates of these measurement points, and used these to perform principal component analysis to investigate trends in the morphology of the auricular surface of the ilium. We found that the morphology of the auricular surface of the ilium could be characterized in terms of (i) size, (ii) concavity of the posterior border and (iii) amount of undulation. An investigation of the correlation between these parameters and age suggested that the amount of undulation of the auricular surface of the ilium tends to diminish with advancing age. In an investigation of the association between morphology of the auricular surface of the ilium and degeneration of the articular surface when the subjects were divided into a high-degeneration group (n=55) and a low-degeneration group (n=45) and the 16 parameters were compared, there was a significant difference in the amount of undulation of the auricular surface of the ilium. In an investigation limited to older subjects aged ≥60 (n=47) at the time of death, there were significant differences between the high-degeneration group (n=27) and low-degeneration group (n=20) in terms not only of the parameters indicating the amount of undulation of the auricular surface of the ilium but also of those indicating the amount of the concavity of the posterior border. These results suggested that the amount of undulation of the auricular surface of the ilium may affect the degree of degeneration of the articular surface. In addition, in older subjects, the degree of concavity of the posterior border of the SIJ may also affect the degree of degeneration of the articular surface. It is thus likely that differences in the morphology of the auricular surface of the ilium may affect degenerative changes in the SIJ.

A test of four innominate bone age assessment methods in a modern skeletal collection from Medellin, Colombia

Studying bone collections with known data has proven to be useful in assessing reliability and accuracy of biological profile reconstruction methods used in Forensic Anthropology. Thus, it is necessary to calibrate these methods to clarify issues such as population variability and accuracy of estimations for the elderly. This work considers observations of morphological features examined by four innominate bone age assessment methods: (1) Suchey–Brooks Pubic Symphysis, (2) Lovejoy Iliac Auricular Surface, (3) Buckberry and Chamberlain Iliac Auricular Surface, and (4) Rouge–Maillart Iliac Auricular Surface and Acetabulum. This study conducted a blind test of a sample of 277 individuals from two contemporary skeletal collections from Universal and San Pedro cemeteries in Medellin, for which known pre-mortem data support the statistical analysis of results obtained using the four age assessment methods. Results from every method show tendency to increase bias and inaccuracy in relation to age, but Buckberry–Chamberlain and Rougé–Maillart’s methods are the most precise for this particular Colombian population, where Buckberry–Chamberlain’s is the best for analysis of older individuals.

The auricular surface as age indicator in a modern Greek sample: A test of two qualitative methods

The auricular surface is often found very well preserved, thus age-related changes in this anatomical area can be important for any set of human remains that require identification under different taphonomic conditions. This study tests the Buckberry and Chamberlain (2002) and Schmitt et al. (2005) methods in predicting the age of individuals in a documented sample from Crete, Greece. Both methods were used to record changes on the auricular surface in a mixed-sex sample of 74 individuals, directly as well as through photographs, by two independent observers. Cohen’s kappa and intra class correlation coefficients (ICC) were used in order to assess inter-observer and intra-observer agreement. Results showed than none of the methods predicted age with sufficient accuracy, as high error rates were recorded. The Schmitt et al. (2005) method performed better, mainly because the age ranges it uses are broader. Scoring through photographs does not seem to introduce bias in predicting age, as demonstrated by the high intra-observer agreement rates. Inter-observer agreement was also high. The low intra- and inter-observer error rates suggest that the poor performance of both methods in the Cretan sample is not due to a lack of clarity in the description of the morphological changes recorded on the auricular surface; rather it should be attributed to a poor correlation between these changes and age at death in our material.

New Method for Sex Prediction Using the Human Non‐Adult Auricular Surface of the Ilium in the Collection of Identified Skeletons of the University of Coimbra

AbstractSex estimation in non‐adult skeletons is crucial in bioarchaeology and forensic anthropology. It was not extensively considered in the past, mainly because it was stated that the dimorphic osteological features were difficult to identify before adulthood. Over the past few years, this statement was disproved, and the study of numerous dimorphic non‐adult skeletal traits was approached. This paper presents a new methodology that evaluates the auricular surface of the non‐adult ilia. Several morphological and continuous variables were recorded for 34 individuals (21 females and 13 males) aged between 7 and 18 from the Coimbra Identified Skeletons Collection (University of Coimbra, Portugal).The results show low intra and inter‐observer errors for all the variables, which renders the methodology replicable. Two ratios related to the shape of the anterior area of the auricular surface offer the most dimorphic data (proportions of cases correctly assigned: 0.82 and 0.88; sexual allocation probabilities: 0.85 for both variables). A discriminant function and a logistic regression were developed, which correctly classified the 82.35 and the 88.23% of the individuals, respectively. Moreover, two qualitative variables, referred to as the overall morphology and the apex morphology, also show statistically significant differences between males and females (proportions of correct assignation: 0.82 and 0.76; sexual allocation probabilities: 0.79 and 0.76).These variables can be incorporated in a multifactorial approach together with other indicators already available in the specialised literature in order to help improve the accuracy of the results obtained. This methodological procedure has to be applied with other identified samples, including younger individuals, so as to test whether the trends presented in this context are maintained and are useful in populations from a different geographical provenience. Copyright © 2017 John Wiley & Sons, Ltd.

The influence of bone loss on the three adult age markers of the innominate.

To evaluate the influence of bone loss on the three adult age markers of the innominate, 30 males and 30 females aged between 16 and 80years coming from the British Coventry collection were analyzed. The pubic symphysis, auricular surface, and acetabulum age variables were evaluated following the descriptions of Schmitt, Buckberry-Chamberlain, and Rissech, respectively. The second metacarpal cortical index was used to evaluate bone loss. Possible sexual differences in metrical variables were explored by a Student t-test taking into account the entire sample. The possible relationships between the cortical index and the three age methods' stages were assessed by the Kruskall-Wallis test and Spearman's correlation coefficient. There were no sexual differences in the cortical index. In general, we observed no significant differences between the cortical index in the different stages of the pubic symphysis, auricular surface, or acetabulum variables in men and women. Most correlation coefficients are negatives, and their absolute values are between 0.001 and 0.44, indicating an extremely low influence of bone loss on the analyzed variables. Our findings suggest little influence of bone loss in the three ageing methods. However, further research on this topic is necessary. This is the first study to analyze the influence of bone loss in the ageing changes undergone by the variables of the three adult age indicators of the innominate taking into account both sexes.

Morphometry of the sacrum and its implication on trans-sacral corridors using a computed tomography data-based three-dimensional statistical model

Background ContextTrans-sacral implants are increasingly used to treat fractures of the sacrum, especially for osteoporosis-associated fragility fractures. However, the complex and highly variable sacral anatomy limits their use. It is still not clear which morphologic characteristics are critical to determine the availability and dimensions of trans-sacral corridors. PurposeThis study aims to assess sacral anatomy and its influence on trans-sacral corridors. Study DesignThis study used a computed tomography (CT)-based three-dimensional (3D) statistical size and shape model of the sacrum with multiple morphometric measurements. Materials and MethodsA 3D statistical model was computed using clinical CT data of 92 intact pelvises (mean age 61.5 years). Multiple measurements of the sacrum and the trans-sacral corridors were taken. Descriptive statistics and linear regression were calculated. Shape and size were analyzed using principal component analysis. ResultsThe limiting craniocaudal diameter of the trans-sacral corridor was 13.1 mm (±5 mm) in S1 and 13.8 mm (±2.4 mm) in S2. In S1, the craniocaudal diameter correlated with larger sacral curvature (SC), pelvic incidence (PI), and cranially located auricular surfaces. The presence of an accessory articulation with L5 was associated with a larger trans-sacral corridor S1. In contrast, the craniocaudal diameter of the S2 corridor correlated with more caudally situated auricular surfaces and lower PI. The sacral shape, as demonstrated by the statistical model, was highly variable, which affected the size and availability of trans-sacral corridor S1. Important determinants of trans-sacral corridor S1 were the craniocaudal position of the auricular surfaces and the shape of the sacral ala, which were influenced by SC, sacral height, and PI. ConclusionsThe human sacrum is highly variable in size and shape. The dimensions of trans-sacral corridors depend on the sacral shape and specific morphologic characteristics. Understanding of morphologic variants helps with preoperative assessments of the trans-sacral corridors. When planning to use trans-sacral implants, because of variable sacral anatomy and dimensions of the trans-sacral corridors, thorough preoperative planning is mandatory.

Geometric morphometric and traditional methods for sex assessment using the posterior ilium.

The human hip bone is generally accepted as the most reliable bone for sex estimation in forensic and bioarchaeological disciplines. However, it is seldom completely preserved. The best preserved region is typically around the sacroiliac joint and its auricular surface; it is therefore surprising that this surface has not been involved in standard sexing methods. The aim of this study was to explore the shape and size sexual dimorphism of the auricular surface in detail and to compare its sex estimation accuracy using the geometric morphometric (GM) and traditional methodological approach. Our sample consisted of 121 specimens from 3 European osteological collections. The GM part of the study was based on 2D sliding semilandmarks that covered the outline of the auricular surface. Furthermore, several linear measurements and visual features (e.g. auricular surface elevation, postauricular sulcus) were chosen to test sex estimation accuracy using support vector machines. Concerning the GM analysis, the most notable sexual differences in the auricular surface outline relate to size. The best accuracy was achieved using form variables reaching 81.0%. Comparable accuracy (80.2%) was achieved using the metric approach, but combined with visual features the accuracy was increased to 93.4%. The GM approach was not very efficient in sexing the auricular surface outline, but the combination of visual features from the posterior ilium and metric variables of the auricular surface could be useful in sex estimation. Therefore, we provide a further testable linear discriminant equation based on this combination of variables.

Inaccuracy and bias in adult skeletal age estimation: Assessing the reliability of eight methods on individuals of varying body sizes

Accurate age estimations are essential for identifying human skeletal remains and narrowing missing persons searches. This study examines how BMI, body mass, and stature influence inaccuracy and bias in adult skeletal age estimations obtained using eight methods. 746 skeletons from the Hamann-Todd and William Bass Collections were used. Underweight BMI, light body mass, and short-stature individuals have the most error associated with their age estimates and are consistently under-aged between 3 to 13years. Obese BMI, heavy body mass, and tall-stature individuals are consistently over-aged between 3 to 8.5years. The most reliable methods for smaller-bodied individuals are Kunos et al. (first rib) and Buckberry-Chamberlain (auricular surface); for individuals in the average range, İşcan et al. (fourth ribs) and Passalacqua (sacrum); and for larger-bodied individuals, İşcan et al., Passalacqua, and Rougé-Maillart et al. (auricular surface and acetabulum). Lovejoy et al. (auricular surface) and Suchey-Brooks (pubic symphysis) produce consistent inaccuracy and bias scores across all body size groups. The least reliable method for smaller-bodied individuals is İşcan et al.; for larger-bodied individuals, Buckberry-Chamberlain; and across all body size groups, DiGangi et al. (first rib).

Reliability of age estimation from iliac auricular surface in a subactual Chilean sample

The aim of this study was to test the reliability of Osborne et al. (2004) [8] age estimation based on the iliac auricular surface of the ilium. We selected 172 skeletons with documented sex and age-at-death and established six uniformly distributed age intervals for analysis. ANOVA was employed to assess the association of the documented age with sex and the auricular surface classification. We employed Bonferroni post-hoc tests to find any statistical differences across documented ages within each phase of Osborne's criteria. While the ANOVA showed a significant association between the documented age and the auricular surface classification, post-hoc tests found that phases 2 and 3 were the only consecutive phases with significant differences. We argue that a lack of statistical significance between consecutive phases undermines the reliability of this method for forensic purposes especially in middle adults. It may be possible that the collapse of intermediate phases would increase the accuracy of this method.

Does Pelvic Incidence Influence the Morphology of the Sacroiliac Joint

Pelvic Incidence is defined as the angle between the perpendicular line to the upper plate of S1 at its midpoint and the line between this point and the center of bicoxofemoral line, it describes the position of femural heads in relation to sacrum. Recently some authors described a direct correlation between high values of PI and large AP pelvic axis (horizontal pelvis) and a wide pelvic ring [1]. Also the acetabular orientation is influenced by PI ; high values of PI means a more vertical acetabulum. Having regard to the relationship between PI and the main structures involved in the load transfer, to date no studies that correlate the morphology of the Sacroiliac Joint (SiJ) and PI were performed. The aim of this study is to evaluate the different morphology of the auricular surface of the sacrum comparing two groups of healthy young people with low ( 40°) PI. We retrospectively analysed 51 consecutive young (between 20 and 35 y.o.) people. After the evaluation of PI the sample was divided into two groups: 31 people belong to the group A (PI 40°). The following morphological parameters of the SiJ were analysed: length of long axis (LLA), length of short axis (LSA), length of oblique axis (LOA), ratio between long and short axis (RLSA), angle between axis (ABA) and surface; global shape of the joint was evaluated; two new parameters were introduced, SiJ Tilt (SiJT), defined as the angle between the vertical line and the long axis of the SiJ and SiJ Slope (SiJS), defined as the angle between the horizontal line and the short axis of the SiJ. We found a strong statistically significant correlations (p-value 0.05) between PI and RLSA, shape, ABA, SiJT and SiJS; a weaker correlations (p-value 0.10) between PI and LLA, LSA were observed; no statistically significant correlation between PI and LOA and surface were observed. The results underline that there is a strong correlation between pelvic morphology and SiJ anatomy. Further studies, about the different pattern of forces distribution among SiJ, will need to be performed to have a better knowledge that could help to understand the biomechanics and pathophysiology of normal and pathological SiJ.

The Use of Informative Priors in Bayesian Modeling Age-at-death; a Quick Look at Chronological and Biological Age Changes in the Sacroiliac Joint in American Males.

The aim of this study is to examine how well different informative priors model age-at-death in Bayesian statistics, which will shed light on how the skeleton ages, particularly at the sacroiliac joint. Data from four samples were compared for their performance as informative priors for auricular surface age-at-death estimation: (1) American population from US Census data; (2) county data from the US Census data; (3) a local cemetery; and (4) a skeletal collection. The skeletal collection and cemetery are located within the county that was sampled. A Gompertz model was applied to compare survivorship across the four samples. Transition analysis parameters, coupled with the generated Gompertz parameters, were input into Bayes' theorem to generate highest posterior density ranges from posterior density functions. Transition analysis describes the age at which an individual transitions from one age phase to another. The result is age ranges that should describe the chronological age of 90% of the individuals who fall in a particular phase. Cumulative binomial tests indicate the method performed lower than 90% at capturing chronological age as assigned to a biological phase, despite wide age ranges at older ages. The samples performed similarly overall, despite small differences in survivorship. Collectively, these results show that as we age, the senescence pattern becomes more variable. More local samples performed better at describing the aging process than more general samples, which implies practitioners need to consider sample selection when using the literature to diagnose and work with patients with sacroiliac joint pain.

An Alternative Posterosuperior Auricular Fascia Flap for Ear Elevation During Microtia Reconstruction.

Advances in staged total auricular reconstruction have resulted in improved anterior auricular appearance; however, satisfactory postreconstruction esthetics of the retroauricular fold remain challenging. The postauricular appearance of the reconstructed ear depends largely upon optimizing the covering material. When used as the covering soft tissue for ear elevation, a flap containing primarily the upper portion of the retroauricular fascia has potential advantages over the conventional book cover-type retroauricular fascia flap. We developed a geometrically designed, posterosuperior auricular fascia flap to replace the conventional retroauricular fascia flap for ear elevation. During the second-stage operation, the posterosuperior auricular fascia flap is rotated downward and turned over to wrap around the inner strut and entire posterior auricular surface. Compared to the conventional book cover-type retroauricular fascia flap, the novel posterosuperior auricular fascia flap was easier to harvest and the operative time significantly decreased (110.3 vs. 121.5min, p<0.01). The modified flap produced a thin and natural contour of the postauricular surface, as well as reduced the incidence of postauricular hypertrophic scarring (from 24.7 to 13.2%, p=0.03) and partial skin graft necrosis (from 43.4 to 31.2%, p=0.01). The geometrically designed posterosuperior auricular fascia flap improves ear elevation. Compared to the conventional book cover-type retroauricular fascia flap, this covering tissue is easier to perform so the surgical time is decreased. It was highly vascularized, well defined, thinner, and yields reliable results. Thus, favorable postauricular surface results can be achieved during auricular reconstruction by using the modified fascia flap. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

The Issue of Age Estimation in a Modern Skeletal Population: Are Even the More Modern Current Aging Methods Satisfactory for the Elderly?,

The main idea behind age assessment in adults is related to the analysis of the physiological degeneration of particular skeletal structures with age. The main issues with these procedures are due to the fact that they have not been tested on different modern populations and in different taphonomic contexts and that they tend to underestimate the age of older individuals. The purpose of this study was to test the applicability and the reliability of these methods on a contemporary population of skeletal remains of 145 elderly individuals of known sex and age. The results show that, due to taphonomic influences, some skeletal sites showed a lower survival. Therefore, the methods with the highest percentage of applicability were Lovejoy (89.6%) and Rougé-Maillart (81.3%), followed by Suchey-Brooks (59.3%), and those with the lowest percentage of applicability were Beauthier (26.2%) and Iscan (22.7%). In addition, this research has shown how for older adults the study of both acetabulum and auricular surface may be more reliable for aging. This is also in accordance with the fact that auricular surface and the acetabulum are the areas more frequently surviving taphonomic insult.

Efficacy of Acupuncture Treatment on Myofascial Pain Syndrome in Upper Trapezius

Upper trapezius myofascial pain syndrome is one of the most common musculoskeletal impairments. Hyper-irritable pain can be intensified due to muscle contraction either at rest or during movement. In traditional Chinese medicine, the Jian Jing (GB21) acupoint is most commonly used to treat pain, neck stiffness, shoulder tension, and headaches. Subjects were recruited for this study at the local outpatient center and randomly assigned into an experimental group with 40-mm-long acupuncture needling or a placebo group with 2.5-mm-long auricular needling. A pressure pain algometer was used to measure the pressure pain threshold (PPT) before and after needling, and two sets of electromyography (EMG) electrodes were attached on both shoulders to measure the trapezius muscle activity during a shoulder shrug motion. The PPT and EMG data were recorded and analyzed to compare different needling depths in suppressing the muscular pain. Twenty-four participants completed the 3-week experiment. The outcomes indicated that there was no substantial difference in PPT pre- and post-treatment between groups. The root-mean-square and integrated EMG activities showed significant decreases during the shrugging motion after each 20-mm-deep acupuncture treatment for the experimental group, but not in the placebo group with the 2.5-mm-deep surface acupuncture. Although the pain tolerance threshold showed a tendency towards improvement, it was not statistically significant, while the placebo group showed almost no treatment effect. Comparing the effects of insertion depth i.e., acupuncture and auricular surface needling, the EMG data indicate that deep acupuncture is an effective treatment for the management of trapezium myofascial pain as it can ameliorate the muscle fatigue of the upper trapezius due to prolong unchanged posture.

Evaluating osteological ageing from digital data.

Age at death estimation of human skeletal remains is one of the key issues in constructing a biological profile both in forensic and archaeological contexts. The traditional adult osteological methods evaluate macroscopically the morphological changes that occur with increasing age of specific skeletal indicators, such as the cranial sutures, the pubic bone, the auricular surface of the ilium and the sternal end of the ribs. Technologies such as computed tomography and laser scanning are becoming more widely used in anthropology, and several new methods have been developed. This review focuses on how the osteological age-related changes have been evaluated in digital data. First, the 3D virtual copies of the bones have been used to mimic the appearance of the dry bones and the application of the traditional methods. Secondly, the information directly extrapolated from CT scans has been used to assess qualitatively or quantitatively the changes of the trabecular bones, the thickness of the cortical bones, and to perform morphometric analyses. Lastly, the most innovative approach has been the mathematical quantification of the changes of the pelvic joints, calculating the complexity of the surface. The importance of new updated reference datasets, created thanks to the use of CT scanning in forensic settings, is also discussed.

Morphology of Sacrum and its Variations

Sacrum is formed by the fusion of five Sacral vertebrae and forms the lower part of Vertebral column. The opening present at the lower end of Sacral canal is known as Sacral hiatus. Anatomical variations, Morphology and Morphometry of Sacral hiatus are important clinically as well as surgically 1 . This study was carried out on 75 dry human sacra of unknown sex to know different features of Sacrum, anatomical variations of sacrum and to study the variations of sacral hiatus. Anatomical variations – failure of formation of superior articular process and lamina of left first sacral vertebra, incomplete development and fusion of second sacral vertebra, multiple foramens on either side of spinous process above the sacral hiatus, multiple foramens in the dorsal surface of base of the sacrum behind the auricular surface, incomplete median crest, bilateral five pelvic and dorsal foramens were identified. Various shapes of sacral hiatus were observed which included inverted u, inverted v, irregular, dumbbell and bifid 2 . The apex of sacral hiatus was commonly found at the level of fourth sacral vertebra. The mean length of sacral hiatus was measured. The mean anteroposterior diameter of sacral canal and narrowing of sacral canal at the apex of sacral hiatus was measured 1&2 . The knowledge of anatomical variations of Sacrum and variations of Sacral hiatus are clinically important for Caudal epidural block in Pediatric, Obsteric, Orthopedic, Urologic and Surgical practice. The reliability and success of Caudal epidural block depends upon Knowledge of Variations of Sacrum and Variations of Sacral hiatus.

A Comparison of Different Age Estimation Methods of the Adult Pelvis.

The adult human pelvis is useful to estimate age because it contains three age indicators-the pubic symphysis, auricular surface, and acetabulum. This study tested the accuracy, inaccuracy, and bias of age estimation from the Suchey-Brooks pubic symphysis, Osborne auricular surface, Rissech and Calce acetabulum aging methods, and a summary age of these indicators. The study sample consisted of 212 White individuals with known age and sex from the William M. Bass Donated Skeletal Collection. The Rissech method performed the best, was the most accurate method with smallest inaccuracy and bias, followed by the Osborne, Suchey-Brooks, summary age, and then Calce methods. Though the Pearson correlation showed only the Suchey-Brooks method to correlate significantly with known age, it is likely the Suchey-Brooks study sample coincidentally reflected the age distribution of this test sample. Results suggested that Bayesian prediction may improve age estimation and should be applied to other age indicators.

Degenerative changes of the sacroiliac auricular joint surface-validation of influential factors.

The purpose of this study was to clarify the relevance of degenerative changes in the sacroiliac joint (SIJ) and the joints in the lower limb and lumbar spine using age estimation methods. We also examined the shape of the auricular surface to determine the effect of degenerative changes on each joint. A total of 200 iliac auricular surfaces from 100 Japanese male skeletons were examined macroscopically in accordance with conventional methods of age estimation. From the obtained estimated age, we calculated the deflection values, which represented the degree of degenerative changes of the joints. For comparison, we used osteophyte score data of the hip, knee, and zygapophyseal joints in lumbar spines from previous studies which had used the same bone specimens. As a quantitative indicator of auricular surface morphology, we defined the constriction ratio (CR) of the auricular surface and compared the CR values obtained with various measured values. Degenerative changes in the SIJ were positively correlated with those in both the hip joint and zygapophyseal joint, but a correlation with knee joints was found only on the left side. In skeletons from individuals aged ≥60years as time of death, the CR was significantly different between the group with high scores and those with low scores in both the hip and sacroiliac joints. It has been suggested that degenerative changes in SIJs interact with those in the hip joint and zygapophyseal joint. In addition, the shape of the auricular surface may also be a relevant factor for degenerative changes in these joints.

Morphologic characteristics of sacra associated with assimilation of the last lumbar vertebra.

The impact of lumbosacral transitional states on biomechanics of load transmission between the spine and the legs has been sporadically reported. The aims of the study were to identify morphostructural alterations of sacra associated with assimilation of the last lumbar vertebra and to analyse them in the light of their biomechanical impact. Linear dimensions of sacrum, its body and base and articular surfaces were measured in 31 normal and 41 transitory sacra. Nineteen sacra presented articular and 22 osseous fusion of the last lumbar vertebra. Measured parameters were compared between normal sacra and the two variations of transitory sacra. Sacra with articular fusion of the last lumbar vertebra showed more pronounced concavity of the sacral curvature and wider than long sacral bodies. The first sacral segment was modified, broaden, ventrally wider and elevated. Almost the whole segment bore at its sides auricular surfaces. Very small portion of the segment was non-articular with less pronounced wedging. Sacra with osseous fusion of the last lumbar vertebra showed similar concavity of the sacral curvature as normal sacra, but longer than wide sacral bodies. The ventral sloping half of the newly formed first segment bore auricular surfaces. The non-articular part was enlarged with pronounced wedging. The term "sacralisation" includes both types of transitory sacra with mutually different morphostructural characteristics in contrast to the normal sacra. Analysis of these morphologic variations may help in understanding the different biomechanical properties and patterns of load transmission.