Variation Of Anatomical Structures Research Articles

Particle-Based Shape Modeling for Arbitrary Regions-of-Interest.

Statistical Shape Modeling (SSM) is a quantitative method for analyzing morphological variations in anatomical structures. These analyses often necessitate building models on targeted anatomical regions of interest to focus on specific morphological features. We propose an extension to particle-based shape modeling (PSM), a widely used SSM framework, to allow shape modeling to arbitrary regions of interest. Existing methods to define regions of interest are computationally expensive and have topological limitations. To address these shortcomings, we use mesh fields to define free-form constraints, which allow for delimiting arbitrary regions of interest on shape surfaces. Furthermore, we add a quadratic penalty method to the model optimization to enable computationally efficient enforcement of any combination of cutting-plane and free-form constraints. We demonstrate the effectiveness of this method on a challenging synthetic dataset and two medical datasets.

Comparative morpho-functional analysis of the humerus and ulna in three Western European moles species of the genus Talpa, including the newly described T. aquitania.

The forelimb is involved in many behaviours including locomotion. Notably, the humero-ulnar articulation, implicated in the elbow joint, is of particular importance for both mobility and stability. Functional constraints, induced in part by environmental plasticity, are thought to drive an important part of the bone shape as bone directly responds and remodels in response to both muscle and external forces. In this context, the study of subterranean moles is of particular interest. These moles occupy a hard and heavy medium in comparison with air or water, requiring a powerful body structure to shear and shift the soil. Their general morphology is therefore adapted to digging and to their subterranean lifestyle. The various morpho-functional patterns, which drive diverse abilities according to the environment, are likely targets of natural selection and it is, therefore, useful to understand the relationships between the bone shape and their function. Here, we quantify, through 3D geometric morphometric methods, the interspecific variability in the morphology of the ulna and humerus of three Talpa species, including the new species Talpa aquitania, to infer their potential consequence in species digging performance. We also quantify shape covariation and morphological integration between the humerus and the ulna to test whether these bones evolve as a uniform functional unit or as more or less independent modules. Our results show that interspecific anatomical differences in the humerus and ulna exist among the three species. Shape changes are mostly located at the level of joints and muscle attachments. As the species tend to live in allopatry and the fossorial lifestyle induces strong ecological constraints, interspecific variations could be explained by the properties of the environment in which they live, such as the compactness of the soil. Our results also show that the humerus and ulna are highly integrated. The covariation between the humerus and ulna in moles is dominated by variation in the attachment areas and particularly of the attachment areas of shoulder muscles concerning the humerus, which affect the mechanical force deployed during locomotion and digging. This study also highlights that in the new species, T. aquitania, variations in anatomical structure (general shape and joints) exist and are related to the locality of collect of the individuals.

Statistical Shape Model of the Temporal Bone Using Segmentation Propagation.

Automated image registration techniques can successfully determine anatomical variation in human temporal bones with statistical shape modeling. There is a lack of knowledge about inter-patient anatomical variation in the temporal bone. Statistical shape models (SSMs) provide a powerful method for quantifying variation of anatomical structures in medical images but are time-intensive to manually develop. This study presents SSMs of temporal bone anatomy using automated image-registration techniques. Fifty-three cone-beam temporal bone CTs were included for SSM generation. The malleus, incus, stapes, bony labyrinth, and facial nerve were automatically segmented using 3D Slicer and a template-based segmentation propagation technique. Segmentations were then used to construct SSMs using MATLAB. The first three principal components of each SSM were analyzed to describe shape variation. Principal component analysis of middle and inner ear structures revealed novel modes of anatomical variation. The first three principal components for the malleus represented variability in manubrium length (mean: 4.47 mm; ±2-SDs: 4.03-5.03 mm) and rotation about its long axis (±2-SDs: -1.6° to 1.8° posteriorly). The facial nerve exhibits variability in first and second genu angles. The bony labyrinth varies in the angle between the posterior and superior canals (mean: 88.9°; ±2-SDs: 83.7°-95.7°) and cochlear orientation (±2-SDs: -4.0° to 3.0° anterolaterally). SSMs of temporal bone anatomy can inform surgeons on clinically relevant inter-patient variability. Anatomical variation elucidated by these models can provide novel insight into function and pathophysiology. These models also allow further investigation of anatomical variation based on age, BMI, sex, and geographical location.

3D Deep Learning for Anatomical Structure Segmentation in Multiple Imaging Modalities.

Accurate, quantitative segmentation of anatomical structures in radiological scans, such as Magnetic Resonance Imaging (MRI) and Computer Tomography (CT), can produce significant biomarkers and can be integrated into computer-aided assisted diagnosis (CADx) systems to support the interpretation of medical images from multi-protocol scanners. However, there are serious challenges towards developing robust automated segmentation techniques, including high variations in anatomical structure and size, the presence of edge-based artefacts, and heavy un-controlled breathing that can produce blurred motion-based artefacts. This paper presents a novel computing approach for automatic organ and muscle segmentation in medical images from multiple modalities by harnessing the advantages of deep learning techniques in a two-part process. (1) a 3D encoder-decoder, Rb-UNet, builds a localisation model and a 3D Tiramisu network generates a boundary-preserving segmentation model for each target structure; (2) the fully trained Rb-UNet predicts a 3D bounding box encapsulating the target structure of interest, after which the fully trained Tiramisu model performs segmentation to reveal detailed organ or muscle boundaries. The proposed approach is evaluated on six different datasets, including MRI, Dynamic Contrast Enhanced (DCE) MRI and CT scans targeting the pancreas, liver, kidneys and psoas-muscle and achieves quantitative measures of mean Dice similarity coefficient (DSC) that surpass or are comparable with the state-of-the-art. A qualitative evaluation performed by two independent radiologists verified the preservation of detailed organ and muscle boundaries.

Exploring Undergraduate Pharmacy Student Experiences of Learning Human Anatomy Using Cadaveric Specimens

Objective. To gain insights into pharmacy students' experiences in learning human anatomy using qualitative interviews and thematic analysis. Methods. Participants included Master of Pharmacy students at the end of their first year or the beginning of their second year. The study used a transcendental phenomenological design. Data were collected using semi-structured individual interviews that were recorded and transcribed verbatim. Thematic analysis was used to identify structural and textural components of participants' experiences using data management software. Results. Sixteen participants were recruited and interviewed. Students described developing an understanding of anatomy that differed from their previous experiences, focusing on variation in anatomical structures between patients, and developing professional attributes such as empathy and respect. Students described haptic learning that acted as a hook on which to anchor additional learning from textbooks and lectures. Finally, students perceived the experience as valuable to their future careers as caring professionals. Conclusion. The results of this qualitative study demonstrate that the value of teaching anatomy to undergraduate students goes beyond developing a broad knowledge of anatomical structures, but also engages a deeper conceptual appreciation of professionalism, thereby inducting them into a community of professional practice.

Learning Together about Anatomical Variation Across Species: Examples from Veterinary and Medical Education

Exploring the connections among human, animal, and environmental health is a key component of the One Health Initiative and should be incorporated into education programs for the health professions. The One Health Initiative provides a framework of core competencies including domains such as management, communication, leadership, collaboration, and systems thinking. These competencies are especially important in a world with emerging diseases, impacts from climate change, and the growing interface between humans and animals.Here, I provide a few examples of educational activities that highlight the use of comparative anatomy as a mechanism to practice and reinforce skills that emphasize the core competency domains. I also provide additional details on how these educational opportunities can become a regular part of an active and multidisciplinary curriculum of health professions programs. These educational activities include some key features. First, the most conducive active‐learning settings are often in laboratory‐based courses (e.g., gross anatomy, microanatomy). Second, activities are simple and repeatable and focused on concepts that are shared by different learners. Third, activities bring different learners together to share knowledge, experiences, and perspectives on healthcare. Each of these features are mappable to the core competencies and are often already components of the overarching curriculum of traditional health professions programs.Specific examples include having learners from different anatomy courses (e.g., veterinary, human) collect data on variation in anatomical structures, provide background information on the known variation, and describe the variation found in their cohort of specimens. Professional students present their findings to one another, provide context and functional significance, teach each other the anatomy of their profession, and explain why this information would be important for their patients and clients. For example, if students were measuring components of the GI tract, facilitators could include group and class discussions on the potential for shared microbiomes in humans and companion animals, as well as incorporate research articles and information on beneficial and harmful microbes that may be in the GI tracts of the hosts.To emphasize best practices, educators should take advantage of active‐learning settings (i.e., laboratory‐based course components, team‐based learning) to emphasize communication, collaboration, and problem‐solving skills while fostering an educational environment that focuses on knowledge of transdisciplinary sciences, awareness of social and cultural aspects of health, and developing professional characteristics when evaluating policies and interacting with communities. The end objective in these educational activities is to promote awareness and a broad‐based global health perspective, as opposed to an emphasis on specializing early in training. All of these factors highlight the need for a One Health focused education system, that can meet the changing healthcare needs of a global population.Support or Funding InformationAmerican Association of AnatomistsThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Normal Patterns of Nasometric Values in Adult Jordanian Speakers of Arabic.

The study sought to establish normative nasometric values for adult Jordanian speakers of Arabic. Gender-related differences and intraspeaker variability of nasalance scores were investigated. A total of 113 adult speakers of Jordanian Arabic (56 men and 57 women) without speech-language and hearing impairments or craniofacial anomalies ranging in age between 18 and 55 participated in the study. Nasometer II, Model 6400 was used to obtain nasalance scores as speakers produced 3 recitations for each of the 3 standardized passages consisting of an oral passage, an oronasal passage, and nasal sentences. Descriptive statistics of nasalance scores for each passage were obtained and gender-related differences were determined by ANOVA. Standard deviation for the 3 repetitions for each passage was considered an index for intraspeaker variability. Average nasalance for each passage was (11.23%) for the oral passage, (25.48%) for the oronasal passage, and (51.92%) for the nasal sentence. There was no gender effect on nasalance on the oral passage, however women exhibited higher nasalance scores than men on the both oronasal passage (P = 0.002) and nasal sentences (P = 0.017). Intraspeaker variability for all speakers fell below 4.5% with repeated readings. The study provides normative nasometric data for Arabic speaking Jordanian adults to serve as references for the assessment of velopharyngeal dysfunction in craniofacial clinics. Arabic speakers demonstrated different nasalance scores than speakers of other languages. Gender differences can be attributed to variations in anatomical structure and velopharyngeal function between men and women.

Heteropogon contortusBL‐1 (Pilli Grass) and Elevated UV‐B Radiation: The Role of Growth, Physiological, and Biochemical Traits in Determining Forage Productivity and Quality

Exposure to elevated UV-B (eUV-B) is well known for its phytotoxicity, although studies made with UV-B exposure and its impact on grasses are limited especially from tropical countries including India. In this study, responses of a valuable grass species, Heteropogon contortus BL-1, were assessed under eUV-B (over ambient UV-B) at different growth stages. Damage caused by eUV-B was observed in the form of membrane damage and loss of pigments at early stages of growth, whereas tannin, phenol, and protein contents showed their increments at all the growth stages, to overcome the imposed stress. Reducing sugar showed its decline at all the growth stages, whereas starch and sucrose contents were higher mostly at later ages of plant growth. eUV-B caused a marked variations in anatomical structures with increase of mesophyll and spongy parenchymatous cells in leaves to reduce severity of irradiation, to maintain the growth and productivity. The study also highlights the significant negative influence of eUV-B on the growth of H. contortus BL-1 and its adaptive strategy to minimize the negative impacts. With the progression of age, plants although adopted to UV-B stress with maintenance of productivity, but palatability of forage was affected due to increment of tannin content.

Rapid prototyping navigation template assisted cervical screw implantation:a review

The cervical screw fixation has been used widely in the clinic setting due to the high fusion rate, immediate fixation of the surgical segment and good correction of the deformity. However, owing to the variation of anatomical structures and the narrow pedicle screws, it's rather difficult to implant the screws through traditional methods. The perforation rate of the screw is high, which can cause serious complications such as neurovascular injury. In recent years, rapid prototyping navigation templates have been reported in the appilication to assist cervical screw placement for improving the accuracy of screw placement. In this paper, we reviewed and summarized published literatures about navigation template assisted cervical screw implantation in the past 20 years, systematically introduced the methods of producing and using of navigation templates, the development of design concept and the status of application in cervical spine surgery. To date, relevant clinical and cadaveric studies confirm that the use of rapid prototyping navigation template assisted cervical screw placement in cervical surgery can reduce screw perforation rate, intraoperative ionizing radiation injury and operation time, which is worth applying in the clinical practice. However, specific clinical effects of different design types of navigation templates are not well summarized. As a result, more clinical and cadaveric studies comparing the accuracy and safety of navigation templates of different design types are needed to help clinicians select the appropriate navigation template for surgery.

Comparative study of structural and ecophysiological features of lichens of different ecological groups in rocky forest communities of northernmost boreal zone (Karelia, Russia)

The anatomical (thickness of layers of fungal and algal symbionts) and ecophysiological parameters (the content of photosynthetic pigments) of two lichen species (Hypogymnia physodes and Umbilicaria hyperborea) from rocky forest communities of northernmost boreal zone (North-West of Russia) were studied. H. physodes is a lichen with foliose thallus morphology and circumpolar distribution which colonizes almost every substrate. U. hyperborea is strictly epilithic lichen with umbilicate type of thallus morphology and arcto-alpine distribution. Despite the fact that the photobiont in two species are closely related taxa (unicellular green algae of the genus Trebouxia) a high variability of photosynthetic pigments content in H. physodes thalli has been revealed, whereas in U. hyperborea, the mycobiotic showed high structural variability. It can be concluded that both mycobiont and photobiont contribute to their adaptation to environmental factors. In the present study it was obtained that the proportion of variation in anatomical structures and the content of photosynthetic pigments probably less depends on taxonomic position of photobiont and more determined by the plasticity of the individual components of the symbiotrophic organism.

3D multi-scale FCN with random modality voxel dropout learning for Intervertebral Disc Localization and Segmentation from Multi-modality MR Images.

Intervertebral discs (IVDs) are small joints that lie between adjacent vertebrae. The localization and segmentation of IVDs are important for spine disease diagnosis and measurement quantification. However, manual annotation is time-consuming and error-prone with limited reproducibility, particularly for volumetric data. In this work, our goal is to develop an automatic and accurate method based on fully convolutional networks (FCN) for the localization and segmentation of IVDs from multi-modality 3D MR data. Compared with single modality data, multi-modality MR images provide complementary contextual information, which contributes to better recognition performance. However, how to effectively integrate such multi-modality information to generate accurate segmentation results remains to be further explored. In this paper, we present a novel multi-scale and modality dropout learning framework to locate and segment IVDs from four-modality MR images. First, we design a 3D multi-scale context fully convolutional network, which processes the input data in multiple scales of context and then merges the high-level features to enhance the representation capability of the network for handling the scale variation of anatomical structures. Second, to harness the complementary information from different modalities, we present a random modality voxel dropout strategy which alleviates the co-adaption issue and increases the discriminative capability of the network. Our method achieved the 1st place in the MICCAI challenge on automatic localization and segmentation of IVDs from multi-modality MR images, with a mean segmentation Dice coefficient of 91.2% and a mean localization error of 0.62 mm. We further conduct extensive experiments on the extended dataset to validate our method. We demonstrate that the proposed modality dropout strategy with multi-modality images as contextual information improved the segmentation accuracy significantly. Furthermore, experiments conducted on extended data collected from two different time points demonstrate the efficacy of our method on tracking the morphological changes in a longitudinal study.

Bilateral “quadriceps gastrocnemius” and termination of small saphenous vein outside the popliteal fossa in a cadaver

The gastrocnemius muscle located on the posterior compartment of the leg, has two heads. Muscular variations presumably seriously compromise parts of the muscular, vascular, nervous, and skeletal and/or organ systems. The main causes of gastrocnemius muscle variation may be due to an error of embryologic developmental timing or persistence of an embryologic condition. On the other hand, variations in the origin, course, and termination of the superficial veins of the lower limb are common. However, variations of the short saphenous are rarely reported. Knowledge on the anatomical variations of structures has clinical significance to surgeons, radiologists who interpret plain and computerized imaging.

Computed Tomography-Based Occipital Condyle Morphometry in an Indian Population to Assess the Feasibility of Condylar Screws for Occipitocervical Fusion.

Study DesignA retrospective computed tomography (CT)-based morphometric study of 82 occipital condyles in the Indian population, focusing on critical morphometric dimensions with relation to placing condylar screws.PurposeThis study focused on determining the feasibility of placing occipital condylar screws in an Indian population using CT anatomical morphometric data.Overview of LiteratureThe occipital condylar screw is a novel technique being explored as one of the options in occipitocervical stabilization. Sex and ethnic variations in anatomical structures may restrict the feasibility of this technique in some populations. To the best of our knowledge, there are no CT-based data on an Indian population that assess the feasibility of occipital condylar screws.MethodsWe measured the dimensions of 82 occipital condyles in 41 adults on coronal, sagittal, and axial reconstructed CT images. The differences were noted between the right and left sides and also between males and females. Statistical analysis was performed using the t-test, with a p-value of <0.05 considered significant.ResultsMean sagittal length and height were 17.2±1.7 mm and 9.1±1.5 mm, respectively. Mean condylar angle/screw angle was 38.0°±5.5° from midline, with mean condylar length and width of 19.6±2.6 mm and 9.5±1.0 mm, respectively. Average coronal height on the anterior and posterior hypoglossal canal was 10.8±1.4 mm and 9.0±1.4 mm, respectively. The values in females were significantly lower than those in males, except for screw angle and condylar width. Based on Lin et al.'s proposed criteria, eight of 82 condyles were not suitable for condylar screws.ConclusionsPreliminary CT morphometry data of the occipital condyle shows that condylar screws are anatomically feasible in a large portion of the Indian population. However, because a small number of population may not be suitable for this technique, meticulous study of preoperative anatomy using detailed CT data is advised.

Morphometric Study of C1 Pedicle and Feasibility Evaluation of C1 Pedicle Screw Placement with a Novel Clinically Relevant Radiological Classification in an Indian Population.

Study DesignA retrospective computed tomography (CT)-based morphometric study of 84 C1pedicles in an Indian population focusing on critical morphometric dimensions vis-a-vis C1 pedicle screw placement.PurposeTo determine the feasibility of C1 pedicle screw placement in an Indian population and propose a novel classification system for the same.Overview of LiteratureAt present, C1 pedicle screws are rarely used, and very few studies have focused on the feasibility of pedicle screw placement in terms of racial, gender, and ethnic variations in anatomical structures. There are no CT-based data on C1 pedicles that assess the feasibility of pedicle screw placement in the Indian population.MethodsWe measured C1 pedicle diameter on CT coronal scan images of 42 adult patients. Extramedullary height (EMH) and intramedullary height (IMH) were measured. We examined the differences between the right and left atlas pedicles and compared measures between males and females. These data were analyzed using significance tests. Based on the results, we propose a novel classification system, which we believe will help in determining the feasibility of C1 pedicle screw placement.ResultsForty-two adult patients (84 pedicles) were examined. Average EMH and IMH were 4.48±0.91 and 0.86±0.77, respectively. Approximately, 32% of the C1 pedicles had bone thicknesses of <4 mm, 49% had IMH of <1 mm, and 38% had no pedicles. The average thickness in women was 4.21±0.93 mm, which was significantly thinner than that in men (4.73±0.81 mm, p=0.004). Right and left pedicles were not significantly different.ConclusionsOur data indicate that approximately one-third of the Indian population may not be suitable candidates for C1 pedicle screw placement. Caution should be exercised while placing type 1B and type 2 pedicles based on our proposed classification system.

SU‐F‐I‐50: Finite Element‐Based Deformable Image Registration of Lung and Heart

Purpose:Photodynamic therapy (PDT) is used after surgical resection to treat the microscopic disease for malignant pleural mesothelioma and to increase survival rates. Although accurate light delivery is imperative to PDT efficacy, the deformation of the pleural volume during the surgery impacts the delivered light dose. To facilitate treatment planning, we use a finite‐element‐based (FEM) deformable image registration to quantify the anatomical variation of lung and heart volumes between CT pre‐(or post‐) surgery and surface contours obtained during PDT using an infrared camera‐based navigation system (NDI).Methods:NDI is used during PDT to obtain the information of the cumulative light fluence on every cavity surface point that is being treated. A wand, comprised of a modified endotrachial tube filled with Intralipid and an optical fiber inside the tube, is used to deliver the light during PDT. The position of the treatment is tracked using an attachment with nine reflective passive markers that are seen by the NDI system. Then, the position points are plotted as three‐dimensional volume of the pleural cavity using Matlab and Meshlab. A series of computed tomography (CT) scans of the lungs and heart, in the same patient, are also acquired before and after the surgery. The NDI and CT contours are imported into COMSOL Multiphysics, where the FEM‐based deformable image registration is obtained. The NDI and CT contours acquired during and post‐PDT are considered as the reference, and the Pre‐PDT CT contours are used as the target, which will be deformed.Results:Anatomical variation of the lung and heart volumes, taken at different times from different imaging devices, was determined by using our model. The resulting three‐dimensional deformation map along x, y and z‐axes was obtained.Conclusion:Our model fuses images acquired by different modalities and provides insights into the variation in anatomical structures over time.

Effect of fabricated density and bamboo species on physical–mechanical properties of bamboo fiber bundle reinforced composites

Bamboo stems were subjected to a mechanical treatment process for the extraction of bamboo fiber bundles. The fiber bundles were used as reinforcement for the fabrication of high-performance composites with phenolic resins as matrix. The influence of fabricated density and bamboo species on physical–mechanical properties of bamboo fiber bundle reinforced composites (BFCs) was evaluated. The results revealed that BFCs with density of 1200 kg/m3 exhibited lower water absorption, better dimensional stability, and higher mechanical properties with comparison to those with lower density. The changes in microstructures of BFCs with respect to density gave evidence that the high performance of BFCs with high density was due to the almost complete collapse of bamboo lumens, which resulted in the formation of solid bamboo and thin resin films with water resistance ability. BFCs fabricated from five bamboo species all showed better properties compared to commercialized bamboo-based composites. However, significant differences in physical–mechanical properties of BFCs among bamboo species were also found. This may be attributed to the variations in anatomical structure and physical–mechanical properties among original bamboo species. From a practical production view, the effect of bamboo species on properties of BFCs should be properly taken into consideration.

PS-306 Neonatal Lumbar Puncture – Are Clinical Landmarks Accurate?

Background The intercristal line, defined by the superior aspect of the iliac crest, is used to clinically identify the correct position for lumbar puncture in neonates. Accepted practice is to insert the needle in the intervertebral space at L3/4 or L4/5. Aim We hypothesised variation in anatomical structures in term neonates and that the intercristal line might not accurately aid identification of the correct intervertebral space. Method Following ethical approval 30 term neonates were recruited. Paediatricians identified and marked the intercristal line and intervertebral space above, with neonates in left lateral position. The anatomical position of both points and the conus medullaris end point were confirmed using ultrasonography. Results The intercristal line was marked from L2/3 to L5/S1. In 25 neonates (83%) the intercristal line was identified between L3/4 and L4/5. The intervertebral space above this line was marked between L1/2 to L4/5. The potential site for lumbar puncture was identified too high in 11 cases (36%). The end of the conus medullaris ranged from L1 to L3 terminating at L2 or lower in 11 cases (36%). Conclusion There is wide variation in the position of the intercristal line and potential lumbar puncture site. The potential lumbar puncture site was marked higher than anticipated at L2/3 or above in 11 neonates (36%). The end of the conus medullaris was identified in 11 neonates (36%) at L2 or lower. Using the intercristal line to guide lumbar puncture does not appear to be accurate raising the possibility of potential spinal cord damage.

Evidence of Duck Activity Induced Anatomical Structure Change and Lodging Resistance of Rice Plant

The system of rice cultivation associated with duck raising is known as an integrated rice-duck (RD) farming system and has a long history in China and Asia. However, the roles of duck activities on rice physiological characteristics are unknown. Field and laboratory experiments were conducted to investigate mechanical stimulations of duck activities on rice physiological characteristics, and hence on morphology and anatomy. Here, we found that there were substantial variations in anatomical structure of the rice culm internodes and in lodging resistance of rice plants with and without the duck activities. Anatomical analysis showed a distinct difference between the RD and rice-no-duck (RND) treatments in culm wall thickness of the rice internodes. For internode N4, the culm wall from the RD treatment was more than 35% thicker than that from the RND treatment. In general, the epidermal layer of the rice culm was significantly denser for the internodes and the thickness of the culm walls increased from N1 to N4 under the RD farming system. Additionally, the areas of vascular bundles were larger and were better organized and structured in the RD treatment. Our results further revealed that the breaking-resistant strength increased whereas the lodging index of the rice culm decreased with duck activities.

A Biomechanical Modeling Study of the Effects of the Orbicularis Oris Muscle and Jaw Posture on Lip Shape

The authors' general aim is to use biomechanical models of speech articulators to explore how possible variations in anatomical structure contribute to differences in articulatory strategies and phone systems across human populations. Specifically, they investigated 2 issues: (a) the link between lip muscle anatomy and variability in lip gestures and (b) the constraints of coupled lip/jaw biomechanics on jaw posture in labial sounds. The authors used a model coupling the jaw, tongue, and face. First, the influence of the orbicularis oris (OO) anatomical implementation was analyzed by assessing how changes in depth (from epidermis to the skull) and peripheralness (proximity to the lip horn center) affected lip shaping. Second, the capability of the lip/jaw system to generate protrusion and rounding, or labial closure, was evaluated for different jaw heights. Results showed that a peripheral and moderately deep OO implementation is most appropriate for protrusion and rounding; a superficial implementation facilitates closure; protrusion and rounding require a high jaw position; and closure is achievable for various jaw heights. Models provide objective information regarding possible links between anatomical and speech production variability across humans. Comparisons with experimental data will illustrate how motor control and cultural factors cope with these constraints.

Definition of retrosternal thyroid growth

The diagnosis of a retrosternal thyroid growth (RTG) causes extended surgical exploration and a different surgical treatment planning (partial sternotomy, thoracotomy) and is usually made by the help of thyroid scintigraphy and ultrasonography. But both examinations have problems in determining the retrosternal thyroid extend in the complex anatomy of sternal bone and often pathologically altered manubrioclavicular joints (MCJ). This study evaluates the variation of anatomical structures in the upper sternal region, the position of the sternal markers during scintigraphy, and the frequency of enhanced bone metabolism of the MCJs. For this aim, the positions of the upper edges of the MCJs were measured by X-ray fluoroscopy in 50 consecutive patients. To prove the exactness of an external marker as used in thyroid scintigraphy, the variation of the marker position was also determined. The activity in the MCJs was measured semiquantitatively with bone scintigraphy in further 100 patients (mean age: 62.3 yrs, SD: 14.2 yrs). As results, the upper edges of the medial clavicular edges exceed the upper margin of the sternal edge up to 2.7 cm. The distance between the medial clavicular edges ranged from 2.3 - 5.6 cm. The position of the sternal marker was correct in the horizontal deviation (mean: 0.1 cm, SD: 0.48 cm) but too high in the vertical position (mean: 2.2 cm, SD: 0.67 cm). During bone scintigraphy, the MCJs showed no enhanced activitity in 75/200 joints, medium activity in 96/200 joints, and strong enhanced activity in 29/200 joints. In consequence, a high variability in the position of the anatomical structures has to be considered together with a high amount of degenerative alterations. The position of the sternal marker was inappropriate in the vertical direction and overestimated a possible retrosternal growth.