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Formation, structure, and function of extra-skeletal bones in mammals.

Authors :
Nasoori A
Source :
Biological reviews of the Cambridge Philosophical Society [Biol Rev Camb Philos Soc] 2020 Aug; Vol. 95 (4), pp. 986-1019. Date of Electronic Publication: 2020 Apr 27.
Publication Year :
2020

Abstract

This review describes the formation, structure, and function of bony compartments in antlers, horns, ossicones, osteoderm and the os penis/os clitoris (collectively referred to herein as AHOOO structures) in extant mammals. AHOOOs are extra-skeletal bones that originate from subcutaneous (dermal) tissues in a wide variety of mammals, and this review elaborates on the co-development of the bone and skin in these structures. During foetal stages, primordial cells for the bony compartments arise in subcutaneous tissues. The epithelial-mesenchymal transition is assumed to play a key role in the differentiation of bone, cartilage, skin and other tissues in AHOOO structures. AHOOO ossification takes place after skeletal bone formation, and may depend on sexual maturity. Skin keratinization occurs in tandem with ossification and may be under the control of androgens. Both endochondral and intramembranous ossification participate in bony compartment formation. There is variation in gradients of density in different AHOOO structures. These gradients, which vary according to function and species, primarily reduce mechanical stress. Anchorage of AHOOOs to their surrounding tissues fortifies these structures and is accomplished by bone-bone fusion and Sharpey fibres. The presence of the integument is essential for the protection and function of the bony compartments. Three major functions can be attributed to AHOOOs: mechanical, visual, and thermoregulatory. This review provides the first extensive comparative description of the skeletal and integumentary systems of AHOOOs in a variety of mammals.<br /> (© 2020 Cambridge Philosophical Society.)

Details

Language :
English
ISSN :
1469-185X
Volume :
95
Issue :
4
Database :
MEDLINE
Journal :
Biological reviews of the Cambridge Philosophical Society
Publication Type :
Academic Journal
Accession number :
32338826
Full Text :
https://doi.org/10.1111/brv.12597