Fig. 1.

Measurement of vascular orientation and area. Laminarity index (LI) was defined as the ratio of the area of the circular canals to total vascular area. C, circular vascular orientation; O, oblique vascular orientation; R, radial vascular orientation; L, longitudinal vascular orientation. In accordance with the methods of de Margerie (2002), a primary vascular canal was required to exhibit a length/width ratio of 3 : 1 or greater in order to be considered ‘lying in the plane of the section’; otherwise, it was considered a longitudinal (L) canal. It should be noted that in this diagram the circular canals are relatively shorter than those observed in areas of the turkey ulna that have predominant ‘laminar vascularization’ patterns. See text for further details and discussion. (Adapted from de Margerie (2002) with permission of Blackwell Publishing.)