Which structure marked below would be responsible for spreading infection into anterior pa of the middle nasal meatus through the frontonasal duct?
High-Yield Explanation
The frontal sinus drains into the anterior pa of the middle nasal meatus frontonasal duct or infundibulum. A.- Cerebrospinal fluid (CSF) is formed by vascular choroid plexus in the ventricles in the brain; the letter "A" indicates the lateral ventricle. C.- The maxillary sinus lies lateral to the lateral wall of the nasal cavity and inferior to the floor of the orbit. B.- Mastoid air cells communicate with the middle ear cavity through the antrum and aditus. D.- The ethmoid sinus has numerous small cavities and lies between the orbit and the nasal cavity.