This is the single bone of the face. It articulates with the mandibular fossa of the temporal bone, and irritation of this joint leads to the condition known as TMJ syndrome. When we were in nursery school we called it the lower jaw. it has a number of landmarks associated with it including: rami, alveoli, coronoid and condyloid processes, body and mandibular ( sigmoid ) notch. It also houses two important foramina, the mandibular and mental foramina. We find that it is actually two bones in the fetus.