Fig. 5: Progression of human iliac perichondral ossification and the ontogeny of pelvic bipedal musculature.

a, Reconstruction of human pelvis development from gestational weeks 10 to 25 (cartilage is depicted in dark grey, and bone is depicted in white). Perichondral ossification extends radially, whereas the AGZ remains cartilaginous up to gestational week 25. b, Sites of muscle origins (attached and unattached) for the gluteal muscles, rectus femoris, vastus lateralis and iliacus. c, UMAP of WNN for multiomics data from human ilium plus soft tissue at E59, with cell types depicted using the colour scheme in Fig. 2. Muscle cell types (MyoC, MyoProg and MyoProg+Pax7) cluster together. d, H&E staining of a transverse section across E59 human ilium (n = 2), highlighting the attached dorso-lateral muscles and the AGZ (left) with corresponding Visium spatial transcriptomics (right). Visium spatial transcriptomics analysis independently recognizes 11 cell clusters. e, Visium gene expression plots (log-transformed) for E59 human ilium integrated with single-cell RNA-sequencing (scRNA-seq) data for selected cell clusters. ASIS, anterior superior iliac spine. Scale bar, 2 mm.