Final answer:
The trigeminal nerve, specifically the maxillary division or V2, is responsible for sensory innervation of the maxillary sinus and is the nerve associated with discomfort in that area.
Step-by-step explanation:
The nerve responsible for discomfort in the maxillary sinus is the trigeminal nerve. This nerve exits just inferior to the superior orbital fissure and supplies sensory innervation to the cheek, nose, and upper teeth. Within the trigeminal nerve, the maxillary division, also known as V2, specifically carries sensation from the maxillary sinus area. When the cells in the maxillary sinus are traumatized, for instance during a sinus infection or other irritation, chemical messengers such as cytokines, serotonin, and prostaglandins are released. These stimulate the nociceptors, which send pain signals through the trigeminal nerve to the central nervous system.
In the context of dental procedures, the mandibular foramen is another critical area for the administration of anesthesia to numb the lower teeth, as the sensory nerve that enters this foramen supplies the lower teeth. This nerve is part of the mandibular division of the trigeminal nerve (V3). However, it does not have a role in sensations from the maxillary sinus.