Clinical Comment: Referred Pain

REFERRED PAIN  is pain felt in an area remote from the actual site of involvement; however, the two areas ­usually are connected by a sensory nerve network. Frequently, the pathways of the trigeminal nerve are involved in referred pain. A common example is a momentary severe

bilateral­ frontal headache sometimes experienced when an individual­ eats ice cream.5 An abscessed tooth can cause pain described by a patient as ocular pain and should

be suspected when no orbital cause for the pain can be found. This situation likely occurs because the overload of ­sensation carried by the infraorbital nerve from the upper teeth is interpreted by the brain as coming from another area also served by the trigeminal nerve.

Zygomatic Nerve

Sensory fibers from the lateral aspect of the forehead enter the orbit through a foramen in the zygomatic bone as the zygomaticotemporal nerve. Fibers from the lateral aspect of the cheek and lower eyelid enter

the orbit through a foramen in the zygomatic bone as the zygomaticofacial nerve.13 These two nerves join to become the zygomatic nerve and course along the lateral orbital wall, exiting the orbit through the inferior orbital fissure and joining with the maxillary nerve (see Figure 12-1).

Maxillary Nerve Formation

Having been formed by the joining of the infraorbital nerve, the zygomatic nerve, and nerves from the roof of the mouth, upper teeth and gums, and mucous membranes of the cheek, the maxillary nerve traverses the area between the maxilla and the sphenoid bone. As it passes near the pterygopalatine fossa, it receives some autonomic fibers from the pterygopalatine ganglion (see Figure 12-5). (These autonomic fibers are destined for the lacrimal gland and are discussed in Chapter 14.) The maxillary nerve enters the skull through the foramen rotundum.