Polarity of concavo-convex intervertebral joints in the necks and tails of sauropod dinosaurs

Paleobiology ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 624-642 ◽  
Author(s):  
John A. Fronimos ◽  
Jeffrey A. Wilson ◽  
Tomasz K. Baumiller
Keyword(s):  
Cervical Vertebrae ◽  
Opposite Polarity ◽  
The Body ◽  
Physical Models ◽  
Rotational Stability ◽  
Appendicular Skeleton ◽  
Center Of Rotation ◽  
Convex Part ◽  
Caudal Vertebrae ◽  
Photoelastic Analysis

AbstractThe highly elongated necks, and often tails, of sauropod dinosaurs were composed of concavo-convex vertebrae that provided stability without compromising mobility. Polarities of these concavo-convex joints in the neck and tail are anatomically opposite one another but mechanically equivalent. Opisthocoelous cervical vertebrae and procoelous caudal vertebrae have the convex articular face directed away from the body and the concave articular face directed toward the body. This “sauropod-type” polarity is hypothesized to be (1) more resistant to fracturing of the cotylar rim and (2) better stabilized against joint failure by rotation than the opposite polarity. We used physical models to test these two functional hypotheses. Photoelastic analysis of model centra loaded as cantilevers reveals that neither polarity better resists fracture of the cotylar rim; strain magnitude and localization are similar in both polarities. We assessed the rotational stability of concavo-convex joints using pairs of concavo-convex centra loaded near the joint. Sauropod-type joints withstood significantly greater weight before failure occurred, a pattern we interpret to be dependent on the position of the center of rotation, which is always within the convex part of the concavo-convex joint. In sauropod-type joints, the free centrum rotates about a center of rotation that lies within the more stable proximal centrum. In contrast, the opposite polarity results in a free centrum that rotates about an internal point; when the condyle rotates down and out of joint, the distal end rotates back toward the body, unopposed by ligamentous support. Sauropod-type joints remained stable with greater mobility, more mechanically advantageous tensile element insertions, and greater distal loads than the opposite polarity. The advantages conferred by this joint polarity would have facilitated the evolution of hyperelongated necks and tails by sauropods. Polarity of concavo-convex joints of the appendicular skeleton (e.g., hip, shoulder) is also consistent with the demands of rotational stability.

scholarly journals Load Measurement of the Cervical Vertebra C7 and the Head of Passengers of a Car While Driving Across Uneven Terrain

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3849
Author(s):  
Martin Svoboda ◽  
Milan Chalupa ◽  
Karel Jelen ◽  
František Lopot ◽  
Petr Kubový ◽  
...  
Keyword(s):  
Cervical Vertebrae ◽  
Vertical Direction ◽  
Cervical Vertebra ◽  
Parietal Bone ◽  
The Body ◽  
Human Organism ◽  
Dynamic Effects ◽  
The Road ◽  
Real Environment ◽  
On The Road

The article deals with the measurement of dynamic effects that are transmitted to the driver (passenger) when driving in a car over obstacles. The measurements were performed in a real environment on a defined track at different driving speeds and different distributions of obstacles on the road. The reaction of the human organism, respectively the load of the cervical vertebrae and the heads of the driver and passenger, was measured. Experimental measurements were performed for different variants of driving conditions on a 28-year-old and healthy man. The measurement’s main objective was to determine the acceleration values of the seats in the vehicle in the vertical movement of parts of the vehicle cabin and to determine the dynamic effects that are transmitted to the driver and passenger in a car when driving over obstacles. The measurements were performed in a real environment on a defined track at various driving speeds and diverse distributions of obstacles on the road. The acceleration values on the vehicle’s axles and the structure of the driver’s and front passenger’s seats, under the buttocks, at the top of the head (Vertex Parietal Bone) and the C7 cervical vertebra (Vertebra Cervicales), were measured. The result of the experiment was to determine the maximum magnitudes of acceleration in the vertical direction on the body of the driver and the passenger of the vehicle when passing a passenger vehicle over obstacles. The analysis of the experiment’s results is the basis for determining the future direction of the research.

Wolf's Syndrome in Twins — Translocation in The Mother

1976 ◽  
Vol 25 (1) ◽  
pp. 267-270 ◽  
Author(s):  
M. Lévy ◽  
B. Noel ◽  
D. Viola
Keyword(s):  
Cervical Vertebrae ◽  
The Body ◽  
Chromosome 4 ◽  
Back Edge ◽  
Intellectual Level ◽  
Mz Twins

A case of MZ twins, both affected by Wolf's syndrome, is described. Their mother, of subnormal look and low intellectual level is translocated. The children, born with a weight and size much below the average, show a very special morphotype: a hook-nose, an abnormal conformation of the back edge of the nostrils (a protrusion in the shape of a horn overhanging the filtrum), hypertelorism, microcephaly. Great asynchronism in the maturation of the bones and a somatoschisis of the body of the cervical vertebrae are noted. Deletion of the short arm chromosome 4 is juxtacentromeric. The study of blood and tissue groups corroborates monozygosity. Dermatoglyphs are little abnormal and identical in the two children. The mother's family is phenotypically normal. At 19 months of age, measuring is still below 4, psychomotor progress is extremely weak, and convulsions are frequent.

Ordosemys leios, n.gen., n.sp., a new turtle from the Early Cretaceous of the Ordos Basin, Inner Mongolia

1993 ◽  
Vol 30 (10) ◽  
pp. 2128-2138 ◽  
Author(s):  
Donald B. Brinkman ◽  
Jiang-Hua Peng
Keyword(s):  
Early Cretaceous ◽  
Inner Mongolia ◽  
Cervical Vertebrae ◽  
Ordos Basin ◽  
Sister Group ◽  
Sister Group Relationship ◽  
Articular Surfaces ◽  
Caudal Vertebrae ◽  
The Ordos Basin

Ordosemys leios, n.gen., n.sp., from the Early Cretaceous Luohandong Formation, Zhidan Group, Ordos Basin, Inner Mongolia, is a primitive aquatic turtle with a reduced, fenestrated plastron. It shares with the members of the Centrocryptodira the presence of well-formed articular surfaces on the cervical and caudal vertebrae. Within the Centrocryptodira, characters of the cervical vertebrae suggest it is more closely related to the Polycryptodira than is the Meiolaniidae. Ordosemys shares with the Chelydridae the presence of two procoelous anterior caudals, but this character may be primitive for the Polycryptodira. Characters of the basicranial region of the braincase shared by Ordosemys and the Chelonioidea support a sister-group relationship between these two taxa, but a sister-group relationship between Ordosemys and the Polycryptodira is more strongly supported by characters shared by the Chelonioidea and other members of the Polycryptodira.

Caudofemoral musculature and the evolution of theropod locomotion

Paleobiology ◽  
1990 ◽  
Vol 16 (2) ◽  
pp. 170-186 ◽  
Author(s):  
Stephen M. Gatesy
Keyword(s):  
Knee Flexion ◽  
Hind Limb ◽  
The Body ◽  
Avian Evolution ◽  
Theropod Dinosaurs ◽  
Data Support ◽  
Caudal Vertebrae ◽  
Longus Muscle

Living crocodilians and limbed lepidosaurs have a large caudofemoralis longus muscle passing from tail to femur. Anatomical and electromyographic data support the conclusion that the caudofemoralis is the principal femoral retractor and thus serves as the primary propulsive muscle of the hind limb. Osteological evidence of both origin and insertion indicates that a substantial caudofemoralis longus was present in archosaurs primitively and was retained in the clades Dinosauria and Theropoda. Derived theropods (e.g., ornithomimids, deinonychosaurs, Archaeopteryx and birds) exhibit features that indicate a reduction in caudofemoral musculature, including fewer caudal vertebrae, diminished caudal transverse processes, distal specialization of the tail, and loss of the fourth trochanter. This trend culminates in ornithurine birds, which have greatly reduced tails and either have a minute caudofemoralis longus or lack the muscle entirely.As derived theropod dinosaurs, birds represent the best living model for reconstructing extinct nonavian theropods. Bipedal, digitigrade locomotion on fully erect limbs is an avian feature inherited from theropod ancestors. However, the primitive saurian mechanisms of balancing the body (with a large tail) and retracting the limb (with the caudofemoralis longus) were abandoned in the course of avian evolution. This strongly suggests that details of the orientation (subhorizontal femur) and movement (primarily knee flexion) of the hind limb in extant birds are more properly viewed as derived, uniquely avian conditions, rather than as retentions of an ancestral dinosaurian pattern. Although many characters often associated with extant birds appeared much earlier in theropod evolution, reconstructing the locomotion of all theropods as completely birdlike ignores a wealth of differences that characterize birds.

Rack Level Modeling of Air Flow Through Perforated Tile in a Data Center

2012 ◽  
Author(s):  
Vaibhav K. Arghode ◽  
Pramod Kumar ◽  
Yogendra Joshi ◽  
Thomas S. Weiss ◽  
Gary Meyer
Keyword(s):  
Data Center ◽  
Body Force ◽  
Air Flow ◽  
The Body ◽  
Physical Models ◽  
Cfd Modeling ◽  
Computational Time ◽  
Force Model ◽  
Flow Through ◽  
Tile Surface

Effective air flow distribution through perforated tiles is required to efficiently cool servers in a raised floor data center. We present detailed computational fluid dynamics (CFD) modeling of air flow through a perforated tile and its entrance to the adjacent server rack. The realistic geometrical details of the perforated tile, as well as of the rack are included in the model. Generally models for air flow through perforated tiles specify a step pressure loss across the tile surface, or porous jump model based on the tile porosity. An improvement to this includes a momentum source specification above the tile to simulate the acceleration of the air flow through the pores, or body force model. In both of these models geometrical details of tile such as pore locations and shapes are not included. More details increase the grid size as well as the computational time. However, the grid refinement can be controlled to achieve balance between the accuracy and computational time. We compared the results from CFD using geometrical resolution with the porous jump and body force model solution as well as with the measured flow field using Particle Image Velocimetry (PIV) experiments. We observe that including tile geometrical details gives better results as compared to elimination of tile geometrical details and specifying physical models across and above the tile surface. A modification to the body force model is also suggested and improved results were achieved.

scholarly journals Motions models of a two-wheeled experimental sample

2021 ◽  
pp. 40-49
Author(s):  
Anatoliy Kulik ◽  
Konstantin Dergachov ◽  
Sergey Pasichnik ◽  
Sergey Yashyn
Keyword(s):  
Automatic Control ◽  
State Space ◽  
Experimental Model ◽  
Functional Properties ◽  
Angular Position ◽  
The Body ◽  
Angular Motion ◽  
Physical Models ◽  
Experimental Sample ◽  
Electric Drives

The subject of study is the physical processes of translational and angular motion of a two-wheeled experimental sample. The goal is to develop physical, mathematical, and graphic models of the translational and angular motions of a two-wheeled experimental sample as an object of automatic control. The objectives: to form physical models of a two-wheeled experimental sample; to develop a nonlinear mathematical description of the processes of translational and angular sample`s motions using the Lagrange approach; to obtain a linearized mathematical sample`s description as an object of automatic control in the state space and frequency domain; to generate graphic models in the form of structural diagrams in the time and frequency domains; to analyze the functional properties of an object of automatic control: stability, controllability, observability, structural and signal diagnosability concerning violations of the functional properties of electric drives and sensors of the angular position of the body and wheels. The methods of the study: the Lagrange method, Taylor series, state-space method, Laplace transformations, Lyapunov, Kalman criteria, and diagnosability criterion. The results: physical models of a two-wheeled experimental sample have been obtained in the form of a kinematic diagram of the mechanical part and the electric circuit of an electric drive; mathematical descriptions of translational and angular motions have been developed in nonlinear and linearized forms; structural diagrams have been developed; functional characteristics of a two-wheeled experimental model as an object of automatic control have been analyzed to solve problems of control algorithms synthesis. Conclusions. The scientific novelty lies in obtaining new models that describe the translational and angular motion of a two-wheeled experimental model as an object of automatic control. The obtained models differ from the known ones by considering the dynamic properties of sensors and electric drives, as well as the relationship of movements.

scholarly journals «THE HEADLESS HORSEMAN». THE SKYTHIAN GRAVE IN THE BARROW NEAR KUSTORIVKA VILLAGE

2021 ◽  
Vol 40 (3) ◽  
pp. 264-281
Author(s):  
O. D. Kozak ◽  
V. M. Okatenko ◽  
T. V. Bitkovska
Keyword(s):  
Cervical Vertebrae ◽  
Cervical Vertebra ◽  
Human Head ◽  
The Body ◽  
Burial Mound ◽  
Left Femur ◽  
Funeral Rite ◽  
Left Behind ◽  
The North ◽  
Edible Parts

In 2013 near Kustorivka village of Krasnokutsky district, Kharkov region the Scythian burial mound (5th—4th centuries BC.) was excavated. The inserted burial of a beheaded man has been discovered there. Fragments of horse bones, horse harness, numerous arrowheads, the spearhead and knife were unearthed in the grave. Funeral inventory dates the burial to the 2nd half or the end of 5th — the early 4th century BC. The grave goods allowed us to suggest that the man was a horseman and possessed a bow with arrows, javelin or lance. These assumptions have been confirmed by anthropological studies of the development of muscles relief, injuries and specific skeletal markers. The skeleton showed clear signs of a horseman’ and archer’ osteological complexes. The man died at the age of 20—25. The skull, first and second cervical vertebrae were absent in the undisturbed burial. The upper part of the left intervertebral condyle of the 3rd vertebra was cut off by the hit from left behind and below. These signs are evidence of decapitation. In addition, numerous cut marks made with a sharp blade were found on the anterior and lateral surfaces of the 3rd and 4th cervical vertebrae, as well as on the left femur above the knee. Thus could be the signs of the body cleaning of waste tissue for its transportation or in course of the preparation for the burial. Studies of the horse’s remains showed that it has deceased at the age of 10—12 years. The horse was decapitated as well by the hit directed between first and second cervical vertebra. The head was also cut in half and only one part of it was present in the burial. There were also some bones of the animal’s skeleton, which do not belong to the edible parts of the body. The severed head of the horse was located above the place where the man’s head was supposed to be, thus the horse harness was situated on the level of the human skeleton. Traces of the possible preparation of the human body for burial and the location of the remains of a horse over a lost human head along with other changes in the skeleton indicate a certain funeral rite, direct analogies of which have not yet been found in the North Pontic region.

First remingtonocetid archaeocete (Mammalia, Cetacea) from the middle Eocene of Egypt with implications for biogeography and locomotion in early cetacean evolution

2015 ◽  
Vol 89 (5) ◽  
pp. 882-893 ◽  
Author(s):  
Ryan M. Bebej ◽  
Iyad S. Zalmout ◽  
Ahmed A. Abed El-Aziz ◽  
Mohammed Sameh M. Antar ◽  
Philip D. Gingerich
Keyword(s):  
Middle Eocene ◽  
Lumbar Vertebrae ◽  
The Body ◽  
Power Stroke ◽  
Tethys Sea ◽  
Vertebral Centra ◽  
Hind Limbs ◽  
Caudal Vertebrae ◽  
Southern Tethys

AbstractRemingtonocetidae are Eocene archaeocetes that represent a unique experiment in cetacean evolution. They possess long narrow skulls, long necks, fused sacra, and robust hind limbs. Previously described remingtonocetids are known from middle Eocene Lutetian strata in Pakistan and India. Here we describe a new remingtonocetid, Rayanistes afer, n. gen. n. sp., recovered from a middle to late Lutetian interval of the Midawara Formation in Egypt. The holotype preserves a sacrum with four vertebral centra; several lumbar and caudal vertebrae; an innominate with a complete ilium, ischium, and acetabulum; and a nearly complete femur. The ilium and ischium of Rayanistes are bladelike, rising sharply from the body of the innominate anterior and posterior to the acetabulum, and the acetabular notch is narrow. These features are diagnostic of Remingtonocetidae, but their development also shows that Rayanistes had a specialized mode of locomotion. The expanded ischium is larger than that of any other archaeocete, supporting musculature for powerful retraction of the hind limbs during swimming. Posteriorly angled neural spines on lumbar vertebrae and other features indicate increased passive flexibility of the lumbus. Rayanistes probably used its enhanced lumbar flexibility to increase the length of the power stroke during pelvic paddling. Recovery of a remingtonocetid in Egypt broadens the distribution of Remingtonocetidae and shows that protocetids were not the only semiaquatic archaeocetes capable of dispersal across the southern Tethys Sea.

The face and superficial neck

2013 ◽  
Author(s):  
Martin E. Atkinson
Keyword(s):  
Vertebral Column ◽  
Cervical Vertebrae ◽  
Small Body ◽  
Spinous Process ◽  
Odontoid Process ◽  
Cervical Vertebra ◽  
Intervertebral Discs ◽  
The Body ◽  
Thoracic Vertebrae ◽  
The Face

The surface anatomies of the face and neck and their supporting structures that can be palpated have been described in Chapter 20. It is now time to move to the structures that lie under the skin but which cannot be identified by touch starting with the neck and moving up on to the face and scalp. The cervical vertebral column comprises the seven cervical vertebrae and the intervening intervertebral discs. These have the same basic structure as the thoracic vertebrae described in Section 10.1.1. Examine the features of the cervical vertebra shown in Figure 23.1 and compare it with the thoracic vertebra shown in Figure 10.3. You will see that cervical vertebrae have a small body and a large vertebral foramen. They also have two distinguishing features, a bifid spinous process and a transverse foramen, piercing each transverse process; the vertebral vessels travel through these foramina. The first and second vertebrae are modified. The first vertebra, the atlas, has no body. Instead, it has two lateral masses connected by anterior and posterior arches. The lateral masses have concave superior facets which articulate with the occipital condyles where nodding movements of the head take place at the atlanto-occipital joints. The second cervical vertebra, the axis, has a strong odontoid process (or dens because of its supposed resemblance to a tooth) projecting upwards from its body. This process is, in fact, the body of the first vertebra which has fused with the body of the axis instead of being incorporated into the atlas. The front of the dens articulates with the back of the anterior arch of the atlas; rotary (shaking) movements of the head occur at this joint. The seventh cervical vertebra has a very long spinous process which is easily palpable. The primary curvature of the vertebral column is concave forwards and this persists in the thoracic and pelvic regions. In contrast, the cervical and lumbar parts of the vertebral column are convexly curved anteriorly. These anterior curvatures are secondary curvatures which appear in late fetal life. The cervical curvature becomes accentuated in early childhood as the child begins to support its own head and the lumbar curve develops as the child begins to sit up.

The locomotor system

2013 ◽  
Author(s):  
Martin E. Atkinson
Keyword(s):  
Vertebral Column ◽  
Cervical Vertebrae ◽  
Lumbar Vertebrae ◽  
Posterior Wall ◽  
Axial Skeleton ◽  
Intervertebral Discs ◽  
Central Canal ◽  
The Body ◽  
Thoracic Vertebrae ◽  
Locomotor System

The locomotor system comprises the skeleton, composed principally of bone and cartilage, the joints between them, and the muscles which move bones at joints. The skeleton forms a supporting framework for the body and provides the levers to which the muscles are attached to produce movement of parts of the body in relation to each other or movement of the body as a whole in relation to its environment. The skeleton also plays a crucial role in the protection of internal organs. The skeleton is shown in outline in Figure 2.1A. The skull, vertebral column, and ribs together constitute the axial skeleton. This forms, as its name implies, the axis of the body. The skull houses and protects the brain and the eyes and ears; the anatomy of the skull is absolutely fundamental to the understanding of the structure of the head and is covered in detail in Section 4. The vertebral column surrounds and protects the spinal cord which is enclosed in the spinal canal formed by a large central canal in each vertebra. The vertebral column is formed from 33 individual bones although some of these become fused together. The vertebral column and its component bones are shown from the side in Figure 2.1B. There are seven cervical vertebrae in the neck, twelve thoracic vertebrae in the posterior wall of the thorax, five lumbar vertebrae in the small of the back, five fused sacral vertebrae in the pelvis, and four coccygeal vertebrae—the vestigial remnants of a tail. Intervertebral discs separate individual vertebrae from each other and act as a cushion between the adjacent bones; the discs are absent from the fused sacral vertebrae. The cervical vertebrae are small and very mobile, allowing an extensive range of neck movements and hence changes in head position. The first two cervical vertebrae, the atlas and axis, have unusual shapes and specialized joints that allow nodding and shaking movements of the head on the neck. The thoracic vertebrae are relatively immobile. combination of thoracic vertebral column, ribs, and sternum form the thoracic cage that protects the thoracic organs, the heart, and lungs and is intimately involved in ventilation (breathing).

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