Histo-Morphological Study on the Footpad of Ostrich (Struthio camelus) In Relation to Locomotion

Abstract

The ostrich foot has four digital pads, two on the 3 rd digit, one on the 4 th digit and one at metatarso-phalangeal joint. Although these footpads are essential for long distance locomotion of the ostrich, no published data is available on the structure of these footpads. Therefore , the aim of this study is to examine the histo-morphological structure of these footpads in an attempt to highlight their structural functional adaptation for long distance motion. Morphologically, the ventral surface of each footpad is covered by numerous papillae which are varied in direction, length and thickness. In histological examination, the epi-dermis of the footpad consists of outer stratum corneum and inner stratum germinativum (which is subdivided into basal, intermediate and transitional layers). The stratum corneum has several layers of flattened horney cells. The nuclei of the basal cells have several mitotic figures. The cytoplasm of the stratum germinativum cells has multiple lipid droplets and multigranular bodies (in transitional cells only). Using scanning electron microscope, the collagen fibers in the mid and deep dermis of the footpad run parallel and connect to each other by very thin fibrils which are branched, crossed with each other in an oblique direction. Such arrangement of these collagen fibers and thin fibrils and presence of digital cushion are likely to be responsible for absorption of concussion and hence acceleration of the ostrich movement. We have concluded that ostrich footpads have unique modified structures which are adapted for long distance movement and protection of the underlying soft tissues .