Final answer:
The mastoid process is the prominent bulge found posterior and inferior to the external acoustic meatus and serves as an attachment point for neck muscles.
Step-by-step explanation:
The prominent bulge located posterior and inferior to the external acoustic meatus is known as the mastoid process of the temporal bone. This bony structure serves as an attachment point for neck muscles and is important in the anatomy of the ear.
It is not to be confused with the internal acoustic meatus, which is on the medial side of the petrous ridge within the cranial cavity, and allows passage for the nerve from the hearing and equilibrium organs of the inner ear, as well as the nerve that supplies the muscles of the face.