Upper jaw in human cyclopia

In human cyclopia the upper jaw forms a solid bony mass between the median orbit and the oral cavity. The skeletal elements forming the upper jaw have been studied in serial sections through the median third of the head in 3 perinatal human specimens presenting with a median orbit and proboscis. One head was sectioned in the sagittal plane and 2 in the coronal plane. The upper jaw has also been studied in a dried cyclops skull and in a desiccated cyclops head in which the roof of the orbit had been removed. The data obtained demonstrate the particular contributions made by the lacrimal bones, the maxillae and the palatine bones to the upper jaw in human cyclopia. The effects of the absence of the frontonasal process contribution and of the absence of the nasal cavity on the upper jaw in cyclopia are considered.     

Palatine bone in human cyclopia

In human cyclopia, a maxillopalatine mass separates the median orbit from the oral cavity. The palatine component of this bony mass has been studied in serial sections through the median third of the head in three perinatal human specimens presenting with a median orbit and proboscis. One head was sectioned in the sagittal plane and two in the coronal plane. The course of each neurovascular bundle arising from the maxillary artery and nerve was used to facilitate the identification of the various parts of the palatine bone. The data obtained were used to outline the palatine component of the maxillopalatine mass as it presented on the inferior aspect of a dried cyclops skull. The suggestion is made that the abnormalities of the palatine bone in human cyclopia are secondary to the absence of the presphenoid and the nasal cavity.     

In vivo and in vitro bone strain in the owl monkey circumorbital region and the function of the postorbital septum

Anthropoids and tarsiers are the only vertebrates possessing a postorbital septum. This septum, formed by the frontal, alisphenoid, and zygomatic bones, separates the orbital contents from the temporal muscles. Three hypotheses suggest that the postorbital septum evolved to resist stresses acting on the skull during mastication or incision. The facial-torsion hypothesis posits that the septum resists twisting of the face about a rostrocaudal axis during unilateral mastication; the transverse-bending hypothesis argues that the septum resists caudally directed forces acting at the lateral orbital margin during mastication or incision; and the tension hypothesis suggests that the septum resists ventrally directed components of masseter muscle force during mastication and incision. This study evaluates these hypotheses using in vitro and in vivo bone strain data recorded from the circumorbital region of owl monkeys. Incisor loading of an owl monkey skull in vitro bends the face upward in the sagittal plane, compressing the interorbital region rostrocaudally and “buckling” the lateral orbital walls. Unilateral loading of the toothrow in vitro also bends the face in the sagittal plane, compressing the interorbital region rostrocaudally and buckling the working side lateral orbital wall. When the lateral orbital wall is partially cut, so as to reduce the width of its attachment to the braincase, the following changes in circumorbital bone strain patterns occur. During loading of the incisors, lower bone strain magnitudes are recorded in the interorbital region and lateral orbital walls. In contrast, during unilateral loading of the P³, higher bone strain magnitudes are observed in the interorbital region, and generally lower bone strain magnitudes are observed in the lateral orbital walls. During unilateral loading of the M², higher bone strain magnitudes are observed in both the interorbital region and in the lateral orbital wall ipsilateral to the loaded molar. Comparisons of the in vitro results with data gathered in vivo suggest that, during incision and unilateral mastication, the face is subjected to upward bending in the sagittal plane resulting in rostrocaudal compression of the interorbital region. Modeling the lateral orbital walls as curved plates suggests that during mastication the working side wall is buckled due to the dorsally directed component of the maxillary force which causes upward bending of the face in the sagittal plane. The balancing side lateral orbital wall may also be buckled due to upward bending of the face in the sagittal plane as well as being twisted by the caudoventrally directed components of the superficial masseter muscle force. The in vivo data do not exclude the possibility that the postorbital septum functions to improve the structural integrity of the postorbital bar during mastication. However, there is no reason to believe that a more robust postorbital bar could not also perform this function. Hypotheses stating that the postorbital septum originally evolved to reinforce the skull against routine masticatory loads must explain why, rather than evolving a postorbital septum, the stem anthropoids did not simply enlarge their postorbital bars. © 1996 Wiley-Liss, Inc.     

A method for 3D detection of symmetry line in asymmetric postures

The methods for symmetry line detection presented in the literature are typically suited to analyse symmetric upright postures, both standing and seated. The proposed method focuses on the symmetry line detection in subjects assuming asymmetric postures in which this line falls far outside the sagittal plane. The proposed approach evaluates the symmetry line by means of an autoregressive process in order to determine the set of planes suited to slice the back coherently with its geometric spatial configuration. The method is analysed assuming the cutaneous marking as reference and it is compared with a previous one, also developed by these authors. Results are analysed and critically discussed.     

Avian skull morphological evolution: exploring exo- and endocranial covariation with two-block partial least squares

While rostral variation has been the subject of detailed avian evolutionary research, avian skull organization, characterized by a flexed or extended appearance of the skull, has eventually become neglected by mainstream evolutionary inquiries. This study aims to recapture its significance, evaluating possible functional, phylogenetic and developmental factors that may be underlying it. In order to estimate which, and how, elements of the skull intervene in patterning the skull we tested the statistical interplay between a series of old mid-sagittal angular measurements (mostly endocranial) in combination with newly obtained skull metrics based on landmark superimposition methods (exclusively exocranial shape), by means of the statistic-morphometric technique of two-block partial least squares. As classic literature anticipated, we found that the external appearance of the skull corresponds to the way in which the plane of the caudal cranial base is oriented, in connection with the orientations of the plane of the foramen magnum and of the lateral semicircular canal. The pattern of covariation found between metrics conveys flexed or extended appearances of the skull implicitly within a single and statistically significant dimension of covariation. Marked shape changes with which angles covary concentrate at the supraoccipital bone, the cranial base and the antorbital window, whereas the plane measuring the orientation of the anterior portion of the rostrum does not intervene. Statistical covariance between elements of the caudal cranial base and the occiput inplies that morphological integration underlies avian skull macroevolutionary organization as a by-product of the regional concordance of such correlated elements within the early embryonic chordal domain of mesodermic origin.     

Types of body posture and their characteristics in boys 10 to 13 years of age

The main goal of the study was to determine the types of body posture of boys (n = 273), 10 to 13 years of age, by means of the body posture assessment method based on the software Posture Image Analyzer. The results should enable better understanding of postural issues, as well as timely and more precise selection of kinesitherapeutic procedures. Values of 5 front view and 4 sagittal view indicators of standing body posture were measured by means of subjects' photographs and software Image Posture Analyzer Cluster analysis (K-means method) revealed three types of body posture in both the anterior and sagittal plane. Their characteristics were determined with discriminant analysis. In sagittal indicators three posture types are recognizable: (a) correct sagittal body posture (29.3%), (b) mild impaired sagittal body posture (41.8%), (c) marked impaired sagittal body posture (28.9%). In anterior indicators also three posture types are recognizable: (a) correct anterior body posture (19.4%), (b) mild scoliotic body posture in the lumbar region (47.6%), (c) mild scoliotic body posture with double curvature (33%).     

First complete restoration of the Oreopithecus skull

The crushed skull ofOreopithecus bambolii (IGF 11778) has been fully reconstructed in Florence, Italy and shows important differences with previous drawn reconstructions. The jaws are massive and projecting, such that the face is not as short as was believed. The incisors are small and do not project significantly forward beyond the position of the canines, and the anterior symphyseal surface of the mandible projects in front of the canines and well infront of the upper canines and incisors. There is a prominent sagittal crest, a high ascending mandibular ramus, and a nuchal plane which faces postero-inferiorly.     

The lumbosacral transition: morphologic variations and their functional significance

The articular facet of a superior articular process of the sacrum is directed backward, inward, and upward with marked variations. 4 angles characterize the orientation of this facet: a) The relative angle of tilt: i.e. the angle between the articular facet and the upper end-plate of the sacrum, measured in a sagittal plane. b) The absolute angle of tilt: i.e. the angle between the articular facet and the horizontal plane, measured in a sagittal plane. c) The tilted part-angle of opening: i.e. the angle between the articular facet and the sagittal plane, measured in a plane parallel to the upper end-plate of the sacrum. d) The horizontal part-angle of opening: i.e. the angle between the articular facet and the sagittal plane, measured in a horizontal plane. These 4 angles are determined by characteristic straights within the articular facet and certain reference planes (upper end-plate of the sacrum, horizontal plane, sagittal plane). Only 2 intersecting straights suffice for an adequate determination of a geometrical plane; therefore, if we know the relative angle of tilt and the tilted part-angle of opening, we are able to construct or to calculate the absolute angle of tilt as well as the horizontal part-angle of opening by using the range of inclination of the sacrum. The shape as well as the orientation of the articular facets at the superior articular processes of the sacrum do not depend on the inclination of the pelvis nor on the inclination of the sacrum nor on the range of the lumbosacral angle. Only the absolute angle of tilt shows a reference to the inclination of the sacrum because the relative angle of tilt shows a certain constancy. The orientation of the articular facets is slightly influenced by static moments, but considerably determined by dynamical requirements. At spines with irregular numbers of praesacral vertebrae, the orientation of the lumbosacral articular facets do not differ from the orientation of these facets at spines with the regular number of 24 praesacral vertebrae. This, however, does not prove right at spines, that have a lumbosacral "transitional vertebra". Such lumbosacral transitional vertebrae detract much from the stability of the lumbosacral region of the spine.     

Nonlinear analysis of the dynamics of the human balance control system during fixation and smooth pursuit of visual target

The similarity between the dynamics of the human balance control system in the frontal and sagittal planes during the fixation of visual stimulus and smooth pursuit of its sinusoidal movements in the horizontal plane with a frequency of 0.1 or 0.01 Hz (so-named fast and slow pursuit) has been investigated by the nonlinear method of analysis. The experiments were carried out according to the notion that it is possible to describe the process of orthograde standing by a two-segment model--upper and lower segments which are connected by a hip joint (other joints were fixed). It was shown that during fixation the similarity between the dynamics of orthostatic control system in the frontal plane is higher than in the sagittal plane. A slow pursuit does not influence the similarity, but a fast one decreases the similarity in the frontal plane. The indices of similarity between the dynamics of the system in the sagittal plane for all the conditions are close and do not differ significantly. The changes in similarity during fast pursuit are supposed to be connected with the different inertia of eyes and body movements. The differences between dynamic similarity in the frontal and sagittal planes are probably connected with the peculiarities of both balance control during joint fixation and AP-ML control (Winter et al., 1993) under conditions investigated.     

Of arcs and vaults: the biomechanics of bone‐cracking in spotted hyenas (Crocuta crocuta)

The ability to break open large bones has evolved independently in only three groups of carnivorous mammals, all of which have robust teeth, vaulted foreheads, and pronounced sagittal crests. One unusual skull feature, present in bone‐cracking members of the family Hyaenidae, is a caudally elongated frontal sinus, hypothesized to function in resistance to bending and stress dissipation during bone‐cracking. In the present study, we used finite element (FE) analysis to examine patterns of stress distribution in the spotted hyena (Crocuta crocuta) skull during unilateral biting, and inquire about the functional role of the fronto‐parietal sinus in stress dissipation. We constructed and compared three FE models: (1) a ‘normal’ model of an adult Crocuta skull; (2) a model in which the caudal portion of the fronto‐parietal sinus was filled with bone; and (3) a model in which we flattened the sagittal crest to resemble the plate‐like crests of other mammals. During biting, an arc of stress extends from the bite point up through the vaulted forehead and along the sagittal crest. Our results suggest that pneumatization of the hyena's skull both enhances its ability to resist bending and, together with the vaulted forehead, plays a critical role in evenly dissipating stress away from the facial region. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 246–255.     

Significance of nonsagittal power terms in analysis of a dynamic elastic response prosthetic foot.

Dynamic elastic response prosthetic feet generally utilize a solid ankle, limiting dominant motion to the sagittal plane. However, researchers often use total rotational ankle joint power in the analysis of these feet. This investigation measured joint power terms in each plane for the Carbon Copy High Performance prosthetic foot. The significance of the frontal and transverse plane terms was assessed. Addition of these terms to the dominant sagittal power term revealed only slight differences, indicating that the sagittal power term is likely sufficient.     

Anatomical macroelements in the study of craniofacial rat growth.

In order to avoid the arbitrary division of biological structures, rational polynomial interpolants are utilized to study growth. The major advantage of this method is the elimination of artificial internal element boundaries through anatomical structures. Since the boundary element methodology is employed in the finite element setting, other benefits, without additional computer coding, include the ability to use elements with any number of sides and reference frame invariance. Longitudinal landmark coordinates from midsagittal X-ray tracings of 22 albino female rat skulls of various ages were averaged. The skull was partitioned into three macroelements: a neural skull and two functionally distinct portions of the facial skull--olfactory and respiratory. The digital computer programming was carried out in the computer mathematics environment of Mathematica. Maximum elongation ratios were calculated for approximately 400 interior points. The elongation ratios in the neural skull compared well with previously documented growth behavior of internal brain structures. The calculated ratios from the facial skull were used to analyze the behavior of macroelement interpolation close to common anatomical boundaries.     

Separating brain motion into rigid body displacement and deformation under low-severity impacts

The relative motion of the brain with respect to the skull has been widely studied to investigate brain injury mechanisms under impacts, but the motion patterns are not yet thoroughly understood. This work analyzes brain motion patterns using the most recent and advanced experimental relative brain/skull motion data collected under low-severity impacts. With a minimum total pseudo-strain energy, the closed-form solutions for rigid body translation and rotation were obtained by matching measured neutral density target (NDT) positions with initial NDT positions. The brain motion was thus separated into rigid body displacement and deformation. The results show that the brain has nearly pure rigid body displacement at low impact speed. As the impact becomes more severe, the increased brain motion primarily is due to deformation, while the rigid body displacement is limited in magnitude for both translation and rotation. Under low-severity impacts in the sagittal plane, the rigid body brain translation has a magnitude of 4-5 mm, and the whole brain rotation is on the order of +/-5 degrees.     

Phenotypic integration of neurocranium and brain

Evolutionary history of Mammalia provides strong evidence that the morphology of skull and brain change jointly in evolution. Formation and development of brain and skull co-occur and are dependent upon a series of morphogenetic and patterning processes driven by genes and their regulatory programs. Our current concept of skull and brain as separate tissues results in distinct analyses of these tissues by most researchers. In this study, we use 3D computed tomography and magnetic resonance images of pediatric individuals diagnosed with premature closure of cranial sutures (craniosynostosis) to investigate phenotypic relationships between the brain and skull. It has been demonstrated previously that the skull and brain acquire characteristic dysmorphologies in isolated craniosynostosis, but relatively little is known of the developmental interactions that produce these anomalies. Our comparative analysis of phenotypic integration of brain and skull in premature closure of the sagittal and the right coronal sutures demonstrates that brain and skull are strongly integrated and that the significant differences in patterns of association do not occur local to the prematurely closed suture. We posit that the current focus on the suture as the basis for this condition may identify a proximate, but not the ultimate cause for these conditions. Given that premature suture closure reduces the number of cranial bones, and that a persistent loss of skull bones is demonstrated over the approximately 150 million years of synapsid evolution, craniosynostosis may serve as an informative model for evolution of the mammalian skull.     

Discrepancies in knee joint moments using common anatomical frames defined by different palpable landmarks

The aim was to investigate the effects of three anatomical frames using palpable anatomical landmarks of the knee on the net knee joint moments. The femoral epicondyles, femoral condyles, and tibial ridges were used to define the different anatomical frames and the segment end points of the distal femur and proximal tibia, which represent the origin of the tibial coordinate system. Gait data were then collected using the calibrated anatomical system technique (CAST), and the external net knee joint moments in the sagittal, coronal, and transverse planes were calculated based upon the three anatomical frames. Peak knee moments were found to be significantly different in the sagittal plane by approximately 25% (p 相似文献   

结合改进卷积神经网络和最小二乘法的颅骨性别鉴定

颅骨性别鉴定在法医学和颅骨面貌复原等领域具有重要研究意义和应用价值,针对传统颅骨性别鉴定需要专家参与且主观性强、计算机辅助方法需要人工标定特征点等问题,本文提出了结合改进卷积神经网络和最小二乘法的颅骨性别鉴定方法。首先,获取三维颅骨模型多角度颅骨图像,利用改进的卷积神经网络计算每个样本的每张图像属于男性和女性的概率;其次,基于概率均值采用最小二乘法计算每张图像对性别鉴定的权重;最后,利用上述步骤得到的最优参数构造决策函数,通过决策值完成颅骨性别鉴定。本文方法抛弃了繁琐的手动测量,对完整颅骨的性别鉴定正确率高达94.4%,对不完整颅骨的性别鉴定正确率高达87.5%,能够获得较好的颅骨性别鉴定性能。     

Response of a human head/neck/upper-torso replica to dynamic loading--I. Physical model

A human head/neck/upper-torso replica was constructed and instrumented and its response to impact and dynamic loading was studied. The model consists of a water-filled cadaver skull; plastic vertebrae, sternum and ribs; silicon rubber disks and ligaments; and fabric muscles. The static behavior of the system under sagittal plane and lateral loading was adjusted so as to correspond to that of cadaver behavior under similar loading. The structure was loaded impulsively by the sudden arrest of a supporting sled running on a track and by direct head impact with a suspended steel ball. The measured response included the head acceleration, the disk pressures, the muscle strains, the intracranial pressures and the skull strains; the sled motion was also monitored. These data were recorded with a microcomputer and oscilloscopes; the overall system deformation was observed by high-speed cameras. The muscle contraction effects were determined with the aid of microcomputer-controlled devices including a vacuum system, solenoid valves and plastic syringes.     

Somatostatin fibers and their relationship to specific cell types (GH and TSH) in the rat anterior pituitary

Fibers immunocytochemically stained for somatostatin (growth hormone-release-inhibiting hormone) were localized in the anterior pituitaries of rats. Initial studies of fiber localization involved the use of thick frozen (30 micron) sections which allowed visualization of fibers as they coursed along the periphery of the anterior lobe in the sagittal plane and along blood vessels throughout the lobe. Fibers were observed most often at the rostral, caudal, and lateral poles. In thinner (1-3 micron) paraffin sections, stained somatostatin fibers could be localized in close proximity to cells that were stained for growth hormone or thyroid stimulating hormone in a double stain with a second peroxidase substrate. These and our previous light microscopic studies show that a few neuronal processes containing neurotransmitters extent beyond the level of the median eminence (or perhaps from a peripheral source), penetrate the anterior lobe in specific regions, and lie in close proximity to cells known to be controlled by the transmitter.     

Approximation of the functional kinematics of posterior stabilised total knee replacements using a two-dimensional sagittal plane patello-femoral model: comparing model approximation to in vivo measurement

Previous in vivo studies have observed that current designs of posterior stabilised (PS) total knee replacements (TKRs) may be ineffective in restoring normal kinematics in Late flexion. Computer-based models can prove a useful tool in improving PS knee replacement designs. This study investigates the accuracy of a two-dimensional (2D) sagittal plane model capable of predicting the functional sagittal plane kinematics of PS TKR implanted knees against direct in vivo measurement. Implant constraints are often used as determinants of anterior–posterior tibio-femoral positioning. This allowed the use of a patello-femoral modelling approach to determine the effect of implant constraints. The model was executed using motion simulation software which uses the constraint force algorithm to achieve a solution. A group of 10 patients implanted with Scorpio PS implants were recruited and underwent fluoroscopic imaging of their knees. The fluoroscopic images were used to determine relative implant orientation using a three-dimensional reconstruction method. The determined relative tibio-femoral orientations were then input to the model. The model calculated the patella tendon angles (PTAs) which were then compared with those measured from the in vivo fluoroscopic images. There were no significant differences between the measured and calculated PTAs. The average root mean square error between measured and modelled ranged from 1.17° to 2.10° over the flexion range. A sagittal plane patello-femoral model could conceivably be used to predict the functional 2D kinematics of an implanted knee joint. This may prove particularly useful in optimising PS designs.