Antlers - Evolution, development, structure, composition, and biomechanics of an outstanding type of bone.

Antlers are bony appendages of deer that undergo periodic regeneration from the top of permanent outgrowths (the pedicles) of the frontal bones. Of the "less familiar" bone types whose study was advocated by John Currey to gain a better understanding of structure-function relationships of mineralized tissues and organs, antlers were of special interest to him. The present review summarizes our current knowledge about the evolution, development, structure, mineralization, and biomechanics of antlers and how their formation is affected by environmental factors like nutrition. Furthermore, the potential role of antlers as a model in bone biology and several fields of biomedicine as well as their use as a monitoring tool in environmental studies are discussed. • Antlers are deciduous cranial bony appendages in Cervidae that, except for reindeer, constitute male secondary sex characteristics. • Antlers develop from permanent pedicles, whose growth is dependent on a specialized (antlerogenic) periosteum. • Antlers are the fastest growing bones and are formed by endochondral and perichondral/intramembranous ossification. • Antlers are used for inter-male fighting during the rut and their biomechanical properties are adapted to that role. • Antlers are a model for studying bone growth and mineralization as well as epimorphic regeneration. [ABSTRACT FROM AUTHOR]