Fig. 2

Selection of the regions of interest (ROIs). Transverse virtual sections (CT-scans in the X-Y plane) of the studied bones oriented as for the data acquisition, where the area coloured in orange indicates the central (transverse) slice in the ROI. a glenoid fossa (scapula of Chlamyphorus truncatus ZMB_Mam_6007), scale bar = 3 mm; (b) and (c) humeral head and capitulum, respectively (Cabassous tatouay SMNS-26661), scale bars = 5 mm; (d) and (e) radial head and trochlea, respectively (Euphractus sexcinctus SMNS-26660), scale bars = 2 mm. Three-dimensional (3D) renderings of the relevant bones (right bones seen in lateral view for the scapula and anterior view for the humerus and radius) are displayed as insets. The anatomical orientations (‘Anterior’, ‘Medial’) are only valid for the sections (not for the 3D renderings). ROIs were selected to be as large as possible but excluding the cortex. Note that the slices displayed (centre of each ROI) do not appear as comprising the maximal quantity of trabeculae because the ROI selection was always restricted at its proximal or distal end. See also 3D models in Additional files 2, 3, 4