A method for estimation of lateral and vertical mobility of platycoelous vertebrae of tetrapods

Kuznetsov, Alexander N.; Tereschenko, V. S.

doi:10.1134/s0031030110020139

Cited by 16 publications

(31 citation statements)

References 9 publications

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“…According to previous osteological studies, the C7 of giraffes possesses a long vertebral body, a round articular surface at the caudal joint between the vertebral bodies and large articular facets directed laterally on the posterior articular processes ( table 2 ) [ 4 – 7 ]. These characteristics are generally observed in the vertebrae from C2 to C6 and could be regarded as the features representing high intervertebral flexibility, based on prior studies on the relationships between the vertebral shape and mobility [ 16 , 17 , 20 , 22 , 23 ]. The thoracic vertebrae from T2 to T14 display the vertebral shape representing low intervertebral mobility [ 16 , 17 , 20 , 22 , 23 ].…”

Section: Discussionmentioning

confidence: 99%

“…These characteristics are generally observed in the vertebrae from C2 to C6 and could be regarded as the features representing high intervertebral flexibility, based on prior studies on the relationships between the vertebral shape and mobility [ 16 , 17 , 20 , 22 , 23 ]. The thoracic vertebrae from T2 to T14 display the vertebral shape representing low intervertebral mobility [ 16 , 17 , 20 , 22 , 23 ]. Namely, they present a short vertebral length, a flat articular surface at the caudal joint of the vertebral body, a long neural spine and small articular facets directed medially, just beneath the neural spine with no processes ( table 2 ) [ 6 , 7 ].…”

Section: Discussionmentioning

confidence: 99%

“…The vertebra presents a flat articular surface on the joint between T1 and T2. The long vertebral body, the large articular facets, and the posterior articular process would contribute to facilitating a higher vertebral mobility than that of general thoracic vertebrae [ 17 , 20 , 22 , 23 ]; however, the flat articular surface would enhance the rigidity between the joints [ 20 ]. This suggests that T1 of the giraffe potentially possesses a mobility that is intermediate of that between the general cervical and thoracic vertebrae.…”

Section: Discussionmentioning

confidence: 99%

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Functional cervicothoracic boundary modified by anatomical shifts in the neck of giraffes

Gunji

Endo

2016

R. Soc. open sci.

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Here we examined the kinematic function of the morpho- logically unique first thoracic vertebra in giraffes. The first thoracic vertebra of the giraffe displayed similar shape to the seventh cervical vertebra in general ruminants. The flexion experiment using giraffe carcasses demonstrated that the first thoracic vertebra exhibited a higher dorsoventral mobility than other thoracic vertebrae. Despite the presence of costovertebral joints, restriction in the intervertebral movement imposed by ribs is minimized around the first thoracic vertebra by subtle changes of the articular system between the vertebra and ribs. The attachment area of musculus longus colli, mainly responsible for ventral flexion of the neck, is partly shifted posteriorly in the giraffe so that the force generated by muscles is exerted on the cervical vertebrae and on the first thoracic vertebra. These anatomical modifications allow the first thoracic vertebra to adopt the kinematic function of a cervical vertebra in giraffes. The novel movable articulation in the thorax functions as a fulcrum of neck movement and results in a large displacement of reachable space in the cranial end of the neck. The unique first thoracic vertebra in giraffes provides higher flexibility to the neck and may provide advantages for high browsing and/or male competition behaviours specific to giraffes.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Functional cervicothoracic boundary modified by anatomical shifts in the neck of giraffes

Gunji

Endo

2016

R. Soc. open sci.

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“…For vertebrates with amphiarthrotic amphiplatyan central articulations (such as lagomorphs, felids and humans), the instantaneous rotation center is not fixed, but rather, shifts depending upon the mechanical properties of the soft tissues and the instantaneous loading [72], [73]. Especially in those mammals such as lagomorphs whose cervical vertebrae are separated by a compressible nucleus pulposus, the resultant curvature of the column in life represents a reaction to all compressive, tensile and shearing forces imposed along the column, and a ‘dry bones’ articulation [12] would be expected to fail to predict either the column's curvature or flexibility in life.…”

Section: Methodsmentioning

confidence: 99%

The Articulation of Sauropod Necks: Methodology and Mythology

Stevens

2013

PLoS ONE

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Sauropods are often imagined to have held their heads high atop necks that ascended in a sweeping curve that was formed either intrinsically because of the shape of their vertebrae, or behaviorally by lifting the head, or both. Their necks are also popularly depicted in life with poses suggesting avian flexibility. The grounds for such interpretations are examined in terms of vertebral osteology, inferences about missing soft tissues, intervertebral flexibility, and behavior. Osteologically, the pronounced opisthocoely and conformal central and zygapophyseal articular surfaces strongly constrain the reconstruction of the cervical vertebral column. The sauropod cervico-dorsal vertebral column is essentially straight, in contrast to the curvature exhibited in those extant vertebrates that naturally hold their heads above rising necks. Regarding flexibility, extant vertebrates with homologous articular geometries preserve a degree of zygapophyseal overlap at the limits of deflection, a constraint that is further restricted by soft tissues. Sauropod necks, if similarly constrained, were capable of sweeping out large feeding surfaces, yet much less capable of retracting the head to explore the enclosed volume in an avian manner. Behaviorally, modern vertebrates generally assume characteristic neck postures which are close to the intrinsic curvature of the undeflected neck. With the exception of some vertebrates that can retract their heads to balance above their shoulders at rest (e.g., felids, lagomorphs, and some ratites), the undeflected neck generally predicts the default head height at rest and during locomotion.

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“…In this context it is also important to mention a study by Kuznetsov and Tereschenko (2010), who investigated the range of motion of the ceratopsian dinosaur Protoceratops andrewsi in comparison to extant sheep and developed a mathematical method for predicting mobility in the dorsoventral and horizontal plane from a set of measurements on the vertebrae. However, they did not calibrate their method with in vivo or ex vivo whole body measurements, but only with dissected specimens subjected to loading experiments (Kuznetsov & Tereschenko, 2010). Although such experiments are highly repeatable, they are questionable in their reliability as recent investigations have shown convincingly that soft tissues have a much higher influence on mobility of the vertebral column than osteology (e.g.…”

Section: Range Of Motionmentioning

confidence: 99%

Using crocodilian tails as models for dinosaur tails

Mallison

Pittman

Schwarz

2015

Preprint

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The tails of extant crocodilians are anatomically the closest approximation of the tails of non-avian dinosaurs, and therefore a good starting point for any reconstruction of non-avian dinosaur tail muscles. However, we here demonstrate some methodological problems using crocodile tails, firstly regarding the general reconstruction of tail mobility from osteology, secondly for the reconstruction of tail musculature for the quantification of muscle forces, especially the m. caudofemoralis longus, and thirdly with respect to the anatomical differences between crocodilians and non-avian dinosaurs, especially in relation to the reconstruction of m. caudofemoralis brevis. Our results show that, given the current limited knowledge of crocodilian tails, volumetric reconstructions should be created on the basis of more gross morphological data than is usually used, and that biomechanical studies should include sensitivity analysis with greater parameter ranges than often applied.

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A method for estimation of lateral and vertical mobility of platycoelous vertebrae of tetrapods

Cited by 16 publications

References 9 publications

Functional cervicothoracic boundary modified by anatomical shifts in the neck of giraffes

Functional cervicothoracic boundary modified by anatomical shifts in the neck of giraffes

The Articulation of Sauropod Necks: Methodology and Mythology

Using crocodilian tails as models for dinosaur tails

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