Final answer:
The narrow extension that connects the frontal bone with the zygomatic bone is called the zygomatic arch. It is formed by the temporal process of the zygomatic bone and the zygomatic process of the temporal bone.
Step-by-step explanation:
The narrow extension that connects the frontal bone with the zygomatic bone is called zygomatic arch. The zygomatic arch is formed by the junction of two bony processes, the temporal process of the zygomatic bone (cheekbone) in the anterior and the zygomatic process of the temporal bone in the posterior. It acts like a drawbridge, joining the two ends together. The zygomatic arch contributes to the lateral wall of the orbit and the lateral-inferior margins of the anterior orbital opening.