Final answer:
The glossopharyngeal nerve (cranial nerve IX) supplies the middle ear, antrum, and eustachian tube with sensory and secretomotor fibers for sensation and certain autonomic functions.
Step-by-step explanation:
The middle ear, antrum, and eustachian tube are supplied by a variety of nerves. The main nerve that provides sensation to these structures is the glossopharyngeal nerve (cranial nerve IX). This nerve innervates the middle ear and the Eustachian tube, playing a critical role in the sensation and autonomic control within these regions. Sensory and secretomotor fibers of this nerve are responsible for transmitting sensations and regulating certain functions in the middle ear cavity and the Eustachian tube.