Date Published: June 11, 2019
Publisher: Public Library of Science
Author(s): Martin J. Schmidt, Gerhard Steenkamp, Klaus Failing, Peter Caldwell, Robert M. Kirberger, Andrew Cuff.
http://doi.org/10.1371/journal.pone.0217999
The cheetah’s closest relatives are the cougar and the jaguarundi. Together, these three species form the Puma lineage, one of the eight lineages of the extant felids; the Puma lineage diverged from the rest 6.7 million years ago. The sister group of the Puma lineage is a clade of smaller Old World cats that includes the genera Felis, Otocolobus and Prionailurus. |
Medical radiography is a broad term that covers several types of studies that require the visualization of the internal parts of the body using x-ray techniques. For the purposes of this page, radiography means a technique for generating and recording an x-ray pattern for the purpose of providing the user with a static image(s) after termination of the exposure. |

Abstract
The aim of this retrospective cross-sectional study was to present comprehensive information about the age-dependent change of skeletal characteristics in captive cheetahs with known age and to assess the benefit of these variables for age estimation in this species. Radiographs of 162 known-age captive and semi-captive cheetahs were retrospectively examined and age-related changes of skull, axial and appendicular skeletal systems were documented. Metric and non-metric variables were used. These parameters were checked for the best correlation with age using a multiple stepwise regression analysis. An overview about the time frames, in which ossification centers appeared and physeal closure occurred is presented.
Multiple stepwise regression analysis revealed the status of closure of the coronal suture, the maximum length of the frontal sinus, the condylobasal-, hard palate, and facial length are most significantly correlated with age. Together with the pulp size of the upper canine, these values can be used for an age approximation in cheetahs.
Source:
http://doi.org/10.1371/journal.pone.0217999
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https://www.fda.gov/radiation-emitting-products/medical-x-ray-imaging/radiography#d