Insights:

The skull is a unique structure, organised by pharyngeal arches and reinforced with neural crest cells.

The skull is divided into neurocranium and viscerocranium. They are further subdivided into a membranous cranium (where bones form via intramembranous ossification) and cartilaginous cranium (endochondral ossification).

The frontal and parietal bones and superior occipital bone form via intramembranous ossification and have sutures between them that fuse following FGF2 signalling. Premature closure results in craniosynostosis and is associated with gain of function mutations in FGFR1 and FGFR2.

The skull base bones form from cartilage models (trabeculae cranii, hypophyseal cartilage, prechordal cartilage, occipital sclerotome). Rostral to the notochord tip, the sphenoid and ethmoid have neural crest contributions.

The facial bones are formed via intramembranous ossification. First pharyngeal arch forms maxillary and mandibular process that forms all the facial bones (mandible, maxilla, zygomatic, squamous temporal, vomer, palatine). First and second pharyngeal arches form the Meckel and Reihart cartilages that form the 3 ossicles of middle ear.

Useful images:

https://skeletalsystemdev.weebly.com/development-of-skull.html

References

Carlson, B. and Kantaputra, P. (2014). Human embryology and developmental biology. Philadelphia, Pa: Saunders/Elsevier.

Sadler, T. and Langman, J. (n.d.). Langman's medical embryology. 10th ed.