Development of the fetal ilium--challenging concepts of bipedality.

Macroradiographs of 30 human fetal and neonatal ilia were analysed to investigate the early pattern of trabecular bone organization prior to the influences of direct weight-bearing locomotion. Consistent and well-defined patterns of internal organization were identified within the fetal and neonatal ilium, which correspond with previously recognized regions that have been attributed directly to forces associated with bipedal locomotion. This study proposes that patterns previously attributed to weight-bearing locomotive responses are present in the earliest stages of the development of this bone. It is suggested that the rudimentary scaffold seen in the fetal and neonatal ilium could indicate a predetermined template upon which locomotive influences may be superimposed and perhaps reinforced at a later age. Alternatively, this early pattern may mimic the adult form due to the effects of in-utero limb movement activity even though it is not weight bearing. This is a preliminary study that will be supported in a further communication with three-dimensional micro-computed trabecular analysis.