Meeting Abstract
Articular geometry is thought to be the primary determinant of joint mobility. However, ontogenetic changes in avian articular morphology remain largely unknown, preventing tests of form-function relationships in developing avian limb joints. Here I present a dataset comprising post-hatching changes in hind limb articular morphology for a representative precocial ground bird, the common quail (Coturnix coturnix). Dissections of quail hind limbs were conducted at five post-hatching age stages to identify ontogenetic changes in joint hard and soft tissues, with particular focus on the appearance of the hip, knee, and ankle joint capsules. Each specimen was then disarticulated and μCT scanned, and differential geometry was applied to articular regions to quantify differences in ossification and 3-D articular shape. Joint capsule ligaments are already present in day-old quail, but become more clearly demarcated in older individuals. Additionally, throughout development, condyles at the knee and ankle become more ossified and strongly defined, changing significantly in their shape and relative size. At each hind limb joint, the coupled changes in mating articular surfaces appear to increase joint congruence. These data suggest that range-of-motion at avian hind limb joints should decrease throughout development, especially in abduction-adduction. Future work will test this hypothesis using cadaveric and living birds to determine if articular morphology is a strong predictor of avian appendicular joint mobility.
