Fig. 5.

Differentiation of cells within cranial sutures. Graphic representation (top) of cranial suture cell populations and their presumptive differentiation pathway. Note: the indicated intramembranous bone stage overtop each region of the suture is not the only composing cell type, however, would likely be found within. In reality, the suture mesenchyme is a heterogeneous population of cells ranging in differentiation from stem cells to committed osteoprogenitors. Corresponding orcein/methylene blue stain (bottom) of the internasal suture of a 4-week old mouse portrays suture mesenchyme in red/brown studded with blue nuclei between two layers of blue cuboidal osteoblasts lining the red/brown bone. Within the lacunae of the bone reside dark blue osteocytes