Sesamoids in tetrapods: the origin of new skeletal morphologies

ABDALA, V.; VERA, MIRIAM CORINA; LUCILA AMADOR; FONTANARROSA, GABRIELA; FRATANI, JÉSSICA; PONSSA MARIA LAURA

BIOLOGICAL REVIEWS OF THE CAMBRIDGE PHILOSOPHICAL SOCIETY

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2019

0006-3231

ababababaAlong with supernumerary bones, sesamoids, defined as any organizedintratendinous/intraligamentous structure, including those composedof fibrocartilage, adjacent to an articulation or joint, have beenfrequently considered as enigmatic structures associated with thejoints of the skeletal system of vertebrates. This review allows usto propose a dynamic model to account for part of skeletal phenotypicdiversity: During evolution, sesamoids become displaced, attach toand detach from the long bone epiphyses and diaphysis. Epiphyses,apophyses and detached sesamoids are able to transform into eachother, contributing to the phenotypic variability of the tetrapodskeleton. This dynamic model is a new paradigm to delineate thecontribution of sesamoids to skeletal diversity. Herein, we firstpresent a historical approach to the study of sesamoids, discussingthe genetic versus epigenetic theories of their genesis andgrowth. Second, we construct a dynamic model. Third, we present asummary of literature on sesamoids of the main groups of tetrapods,including veterinary and human clinical contributions, which are thebest studied aspects of sesamoids in recent decades. Finally, wediscuss the identity of certain structures that have been labelled assesamoids despite insufficient formal testing of homology. We alsopropose a new definition to help the identification of sesamoids ingeneral. This review is particularly timely, given the recentincreasing interest and research activity into the developmentalbiology and mechanics of sesamoids. With this updated and integrativediscussion, we hope to pave the way to improve the understanding ofsesamoid biology and evolution.p { margin-bottom: 0.21cm; direction: ltr; color: rgb(0, 0, 0); }p.western { font-family: "Times New Roman", serif; font-size: 12pt; }p.cjk { font-family: "Times New Roman", serif; font-size: 12pt; }p.ctl { font-family: "Times New Roman", serif; font-size: 12pt; }a.western:link { }a.ctl:link { }