Kinematic constituents of the extreme head turn of Strix aluco estimated by means of CT-scanning

Grytsyshina, E E; Kuznetsov, Alexander N.; Panyutina, Aleksandra A.

doi:10.1134/s0012496616010087

Cited by 9 publications

(32 citation statements)

References 3 publications

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“…Neck rotations of up to 180°are also known from other birds (Dzemski & Christian, 2007), but a 270°neck rotation capability is considered outstanding (Grytsyshina et al 2016). de Kok-Mercado et al (2013) found the arterial canals of the cervical vertebrae of owls to be much wider than the arteries crossing them.…”

Section: Comparison With Morphology Of Bird Neckmentioning

confidence: 99%

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Barn owls maximize head rotations by a combination of yawing and rolling in functionally diverse regions of the neck

et al. 2017

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Owls are known for their outstanding neck mobility: these birds can rotate their heads more than 270°. The anatomical basis of this extraordinary neck rotation ability is not well understood. We used X-ray fluoroscopy of living owls as well as forced neck rotations in dead specimens and computer tomographic (CT) reconstructions to study how the individual cervical joints contribute to head rotation in barn owls (Tyto furcata pratincola). The X-ray data showed the natural posture of the neck, and the reconstructions of the CT-scans provided the shapes of the individual vertebrae. Joint mobility was analyzed in a spherical coordinate system. The rotational capability was described as rotation about the yaw and roll axes. The analyses suggest a functional division of the cervical spine into several regions. Most importantly, an upper region shows high rolling and yawing capabilities. The mobility of the lower, more horizontally oriented joints of the cervical spine is restricted mainly to the roll axis. These rolling movements lead to lateral bending, effectively resulting in a side shift of the head compared with the trunk during large rotations. The joints in the middle of the cervical spine proved to contribute less to head rotation. The analysis of joint mobility demonstrated how owls might maximize horizontal head rotation by a specific and variable combination of yawing and rolling in functionally diverse regions of the neck.

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Section: Comparison With Morphology Of Bird Neckmentioning

confidence: 99%

“…For example, the beak has to reach every feather at the body to allow appropriate plumage care (Stark, 1979). Owls have an outstanding headrotation capability (Grytsyshina et al 2016). This makes owls an interesting study case for neck mobility.…”

Section: Introductionmentioning

confidence: 99%

Barn owls maximize head rotations by a combination of yawing and rolling in functionally diverse regions of the neck

et al. 2017

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“…Estimates of just FE and ABAD (Gishlick, 2001;Carpenter, 2002;Senter & Robins, 2005;Carpenter & Wilson, 2008) are incomplete and ambiguous if LAR is not measured. A few studies have quantified ROM about all three rotational DoFs (3-DoFs) in joints with more complex shapes (Chan, 2007;Pierce et al 2012;Hutson & Hutson, 2013;Arnold et al 2014;Grytsyshina et al 2016), but the analysis, interpretation, and presentation of these data are difficult.…”

Section: Introductionmentioning

confidence: 99%

3‐D range of motion envelopes reveal interacting degrees of freedom in avian hind limb joints

2017

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Measuring range of motion (ROM) is a valuable technique that can link bone morphology to joint function in both extant and extinct taxa. ROM results are commonly presented as tables or graphs of maxima and minima for each rotational degree of freedom. We investigate the interactions among three degrees of freedom using X-ray reconstruction of moving morphology (XROMM) to measure ROM of the main hind limb joints of Helmeted Guineafowl (Numida meleagris). By plotting each rotation on an axis, we generate three-dimensional ROM volumes or envelopes composed of hundreds of extreme joint positions for the hip, knee, and intertarsal joints. We find that the shapes of ROM volumes can be quite complex, and that the contribution of long-axis rotation is often substantial. Plotting in vivo poses from individual birds executing different behaviors shows varying use of potential rotational combinations within their ROM envelopes. XROMM can provide unprecedented high-resolution data on the spatial relationship of skeletal elements and thereby illuminate/elucidate the complex ways in which soft and hard tissues interact to produce functional joints. In joints with three rotational degrees of freedom, two-dimensional representations of ROM (flexion/extension and abduction/adduction) are incomplete.

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“…Functionally, avian necks are typically considered to have substantial mobility in dorsoventral flexion and lateroflexion, while the heterocoelous centra are accepted to preclude significant axial rotation (torsion) in vertebrae caudal to the atlas/axis [23, 26–28]. Quantification of avian cervical joint range of motion (ROM) has frequently been performed passively via hand-manipulation of cadaveric material with and without soft-tissues intact [17, 26, 27, 29–35]; however, a few studies have documented in vivo neck motion (e.g. [17, 32]).…”

Section: Introductionmentioning

confidence: 99%

“…A few studies have quantified lateroflexion in addition to, and independently of, dorsoventral flexion [26, 33]. Only three studies have attempted to reconstruct bird neck movements in three dimensions (specifically in owls [35, 39, 40]), with the potential to quantify all three rotational degrees of freedom simultaneously, including axial rotation. Such data are critical for understanding joint function, as musculoskeletal movements incorporate motion around multiple degrees of freedom simultaneously (e.g.…”

Section: Introductionmentioning

confidence: 99%

Experimental determination of three-dimensional cervical joint mobility in the avian neck

2017

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BackgroundBirds have highly mobile necks, but neither the details of how they realize complex poses nor the evolution of this complex musculoskeletal system is well-understood. Most previous work on avian neck function has focused on dorsoventral flexion, with few studies quantifying lateroflexion or axial rotation. Such data are critical for understanding joint function, as musculoskeletal movements incorporate motion around multiple degrees of freedom simultaneously. Here we use biplanar X-rays on wild turkeys to quantify three-dimensional cervical joint range of motion in an avian neck to determine patterns of mobility along the cranial-caudal axis.ResultsRange of motion can be generalized to a three-region model: cranial joints are ventroflexed with high axial and lateral mobility, caudal joints are dorsiflexed with little axial rotation but high lateroflexion, and middle joints show varying amounts axial rotation and a low degree of lateroflexion. Nonetheless, variation within and between regions is high. To attain complex poses, substantial axial rotation can occur at joints caudal to the atlas/axis complex and zygapophyseal joints can reduce their overlap almost to osteological disarticulation. Degrees of freedom interact at cervical joints; maximum lateroflexion occurs at different dorsoventral flexion angles at different joints, and axial rotation and lateroflexion are strongly coupled. Further, patterns of joint mobility are strongly predicted by cervical morphology.ConclusionBirds attain complex neck poses through a combination of mobile intervertebral joints, coupled rotations, and highly flexible zygapophyseal joints. Cranial-caudal patterns of joint mobility are tightly linked to cervical morphology, such that function can be predicted by form. The technique employed here provides a repeatable protocol for studying neck function in a broad array of taxa that will be directly comparable. It also serves as a foundation for future work on the evolution of neck mobility along the line from non-avian theropod dinosaurs to birds.Electronic supplementary materialThe online version of this article (doi:10.1186/s12983-017-0223-z) contains supplementary material, which is available to authorized users.

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Kinematic constituents of the extreme head turn of Strix aluco estimated by means of CT-scanning

Cited by 9 publications

References 3 publications

Barn owls maximize head rotations by a combination of yawing and rolling in functionally diverse regions of the neck

Barn owls maximize head rotations by a combination of yawing and rolling in functionally diverse regions of the neck

3‐D range of motion envelopes reveal interacting degrees of freedom in avian hind limb joints

Experimental determination of three-dimensional cervical joint mobility in the avian neck

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