The functional matrix hypothesis of craniofacial growth was proposed by Moss. This theory emphasizes that the growth of craniofacial bones is primarily driven by the functional needs of the surrounding soft tissues and spaces, such as muscles, nerves, and organs. The bones act as a secondary adaptive framework responding to the functional demands of these "matrices." Understanding this principle is crucial for surgical planning in craniofacial reconstruction and orthodontics because it highlights the importance of preserving or restoring functional soft tissues to guide optimal bone growth and remodeling.

Reference: Gray's Anatomy, Richard L. Drake, Edition 42