The Sphenoid Sinus Is

Multiple Choice

The sphenoid sinus is:

A) tubular structure which branches off the trachea
B) cavity in the skull which opens into the nasal cavity located between the nose and eyes
C) cavity in the skull which opens into the nasal cavity located in the center of the skull base
D) small flap of cartilage that closes over the trachea preventing food from entering the larynx and thus the lungs