Details of medullary bone found in a single tibia of <i>Dysalotosaurus</i>.

<p>A–H: Large tibia SMNS T3 with images of the preserved medullary bone tissue at the anterior edge of the marrow cavity. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0029958#pone-0029958-g001" target="_blank">Fig. 1G–H</a> for an overview, A – The strongly cancellous medullary bone tissue (mainly in brown colors, under polarized light) is also developed within two large cavities at the edge of the marrow cavity. The difference to the primary bone tissue at the bottom and the CCCB at the lower right is striking. B – Approximately the same as in A under normal light, only slightly rotated image. The strong difference of the medullary bone tissue to the tissue types within the bone wall is still well visible. C – Close up of one part visible in A and B under polarized light. The separation between medullary bone and the actual bone wall tissues is marked by an endosteal layer (arrows). D – The same as in C under normal light. E – Overview of the medial part of the preserved medullary bone tissue under polarized light. The endosteal layer is marked by arrows. F – The same as in E under normal light. G – Magnification of E between its two central arrows under polarized light. The endosteal layer is again marked by an arrow. Note the resorptive nature of this part of the marrow cavity before the development of the endosteal layer. H – Same as in G under normal light. Scale bars = 1 mm in A–B, E–F. Scale bars = 500 µm in C–D. Scale bars = 200 µm in G–H.