Clavicle in Carnivorans: A Forgotten Bone

Abstract

The clavicle is a bone whose development is related to the versatility of the thoracic limbs in mammals. Studies with vestigial structures are scarce and controversial, especially in the order Carnivora. The objective of this study was to verify the presence and to investigate the shape and constitution of the clavicle in neotropical carnivores. In order to do this, 108 cadavers of 19 different species were collected dead on highways and were analyzed. The clavicles were submitted to dissections, longitudinal length measurements, radiographs, histological sections and, in some cases, diaphanization. Sixteen of the 19 species had clavicles in both sides, being significantly larger (P < 0.05) and distinctly more radiopaque in the felids than in the other families. There were no macro or microscopic evidence of clavicle in the specimens of Nasua nasua (n = 6), Conepatus semistriatus (n = 2), and Conepatus chinga (n = 1). The clavicle of the males of Lycalopex gymnocercus, Galictis cuja, and Leopardus geoffroyi was significantly larger (P < 0.05). The predominating contour of the clavicles was a thin stick with cranial convexity. The histological sections demonstrated compact bone consisting of trabecula and lamellae filled by bone marrow and different levels of occupation by chondroid matrix. It can be proposed the clavicles of the order Carnivora, although vestigial and rarely absent, have their presence, constitution and shape more associated with the phylogenetic proximity and evolutionary history of the species than to the variety of movements the thoracic limbs perform in free‐living conditions. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:1831–1841, 2020. © 2019 American Association for Anatomy

Brachial plexus anatomy in the miniature swine as compared to human

“…On the other hand, primates have fully developed clavicle bones. Lagomorpha (including rabbits) and Rodentia (including rats) have variable clavicle development based on family, and Carnivora (including cats and dogs) have vestigial or absent of clavicle bones (de Souza Junior et al, 2020).…”

Bridging mouse and human anatomies; a knowledge-based approach to comparative anatomy for disease model phenotyping

“…In bipedal primates and humans, the clavicle, a bone belonging to the pectoral girdle, is well-developed because there is an adaptation to tasks that depend on using hands distant from the central trunk axis, such as climbing and reaching distant objects (Rockwood et al 2009 ). By contrast, in many quadrupedal mammals, such as ungulates, carnivores and several rodents, the clavicle has disappeared or has been dramatically reduced (De Souza et al 2020 ). This reduction or loss is common to mammals that use the thoracic limb for cursorial locomotion (Rockwood et al 2009 ).…”

Karakteristik Morfofungsi Skelet Ekstremitas Kaki Soa Layar (Hydrosaurus amboinensis)

“…Soa layar memiliki kedua tulang ini yang bersendi di persendian bahu, seperti pada Komodo (Surahya, 1989), tetapi pada buaya Senyulong hanya ditemukan os interclavicula (Puarada, 2017). Manusia dan mamalia brachiate memiliki os clavicula yang berkembang dengan baik, keberadaan tulang ini berhubungan dengan perilakunya seperti memanjat, burning dan menjangkau objek yang jauh (Junior et al, 2020). Hewan ini memiliki os clavicula dan os interclavicula, diduga berfungsi membantu pergerakan lokomotor kaki depan yang berhubungan dengan perilaku memanjat, berlari, dan berenang.…”