The corpus fibulae in sheep (Ovis ammon f. aries) - ontogeny, persistence, size and shape from the fetal period to adulthood

Osteological characteristics are often used to identify animal species. In this regard it is believed that the corpus fibulae of the sheep is represented by a tight cord of connective tissue - the so-called “ligamentum fibulare”. The results of the present morphometric study indicate, however, that in 67% of the fetuses, 61% of the lambs or 48% of the adult sheep out of the 160 examined animals, the corpus fibulae is represented by a pin-shaped flattened piece of bone. The length of the corpus fibulae increases with age and varies greatly between individuals but in lambs and adult animals its centre is located close to the border between the proximal and intermediate third of the tibia (distal type) or closely attached to the caput fibulae by connective tissue fibres (proximal type). The cartilaginous fetal anlage is either transformed to bone or catabolised during fetal life. Desmal ossification should play an important role in the growth of the corpus fibulae since no cartilage could be detected in juvenile and adult sheep. Since there are many similarities in the expression of the corpus fibulae between sheep, goat and fallow deer, this osteological characteristic may not be used for a rapid specific and simple animal species identification procedure.