I want to share all the information I found on another condition quite similar to Eagle Syndrome: Superior Pharyngeal Constrictor Muscle Dysfunction.
I dug into the articles of Dr. Ernest and Dr. Shankland who discovered various pain syndromes originating from muscles close to the styloid process and stylohyoid ligament. To start off with, I urge everyone to read the following article by Dr. Shankland in which he compared five rare throat pain syndromes: Eagle Syndrome, Ernest Syndrome, Superior Pharyngeal Constrictor Muscle Syndrome, Hyoid Bone Syndrome and Carotid Artery Syndrome.
Superior Pharyngeal Constrictor Muscle Dysfunction is most often caused by traumatic injury. Basically, the muscle attaches to the ptyergomandibular raphe, which in turn attaches to the buccinator muscle (see picture below, note the close proximity to the styloid process). Shankland suggests that the ptyergomandibular raphe is permanently damaged after trauma, therefore causing pain in the attaching muscles.
In Shankland’s words: “The basic cause of this type of pharyngeal pain [is] tendonitis of the pterygomandibular raphe. Each time the patient swallows, biomechanical stresses, transferred into and through the raphe, ultimately stimulate nociceptive fibers in the muscle. Sicher stated that this tendinous structure, stretching from the pterygohamulus to the retromolar pad region of the mandible is greatly stretched when the mouth is opened wide. The innervation of this muscle is via the pharyngeal plexus, which is composed of branches of both the glossopharyngeal and vagus nerves.”
The pain is pretty similar to Eagle Syndrome: Throat pain, ear pain, jaw pain, and, as a result of tight muscles, neck pain, etc. Shanklands concludes: “Pain originating from the superior constrictor muscle is often misdiagnosed as Eagle’s syndrome, Ernest syndrome, a temporomandibular disorder, or glossopharyngeal neuralgia.”
Now, research on this condition is scarce and it might be a concomitant of Eagle Syndrome (because the muscle is simply extremely tight) or the actual cause of the pain (because the muscle and/or the ptyergomandibular raphe is damaged). I’m just speculating, but I thought it worth posting here. I encourage everyone to read the articles I’ve linked here as it might prevent you from undergoing an unnecessary Eagle surgery. It’s hard to distinguish between all those throat syndromes - local injections into the muscles and ligaments might determine the root of pain, though.
Additional literature and links: