Superior Pharyngeal Constrictor Muscle Dysfunction
Diffuse facial pain “deep” to the temporomandibular joint with superior pharyngeal muscle soreness and pain, together with ear symptoms, is often enigmatic. This paper is intended to be an introduction to this previously unpublished disorder. This disorder, first documented in 1988, is reported in the author’s yet to be published text entitled Atlas of Diagnostic Anesthesia of the Head & Neck.1 A more detailed article describing multiple case histories will be published in the near future. Many of the cases examined have a traumatic origin from either blunt trauma or motor vehicular accidents. About 90% of the cases treated responded very favorably to infiltration of local anesthetic mixed with an anti-inflammatory medication. The approximate 10% of cases that did not resolve from medicine responded favorably to focal lysis using radiofrequency thermoneurolysis. The oft-repeated observation that painful disorders of the head and neck often may mimic each other’s symptoms is demonstrated with this condition as well.
Superior Pharyngeal Constrictor Muscle
The superior pharyngeal constrictor muscle is an unusual skeletal muscle in that it is very dynamic and complex in function. The muscle is described in Grey’s Anatomy text as a large quadrilateral muscle that arises from four heads of origin (see Figure 1). The origins include the:
- inferior margin of the medial pterygoid plate,
- the pterygomandibular raphe,
- the medial alveolar edge of the mandible above the mylohyoid line, and
- lateral border of the tongue (see Figure 2).
The pharyngeal fibers then curve backward from its origins and are inserted into the median raphe of the posterior pharyngeal wall, and are also prolonged by means of an aponeurosis to the pharyngeal spinous process on the basilar part of the occipital bone.
The prolonged superior pharyngeal fibers also curve just beneath the levator veli palatini muscle and the Eustachian tube. When a bolus of food enters the pharynx, the elevator muscles relax as the pharynx descends, then the constrictor muscles engage and contract on the bolus of food and move it downward into the esophagus.
A dysfunction in the action of the superior pharyngeal constrictor muscle can cause soreness, tightness or pain. There is also the possibility of ear symptoms since the constrictor muscle can affect the eustachian tube and the palatal muscles as well. The author has seen several patients who had areas of local myalgia in the median or pharyngeal raphe at the rear midline of the throat, as well as in the pterygomandibular raphe as well.
An article regarding a facial pain syndrome associated with the mandibular alveolar head of origin of the superior pharyngeal constrictor muscle was previously published in the pages of this journal.3 The signs and symptoms of that condition were very similar to those of stylomandibular ligament injury characterized in the literature as Ernest Syndrome.
Most of the patients seem to have a deep, aching pain at the TMJ that is not relieved with a TMJ splint, medications, or even joint surgery. Given the close proximity of potential pain producing structures, diagnosis can be difficult.
Testing and Treatment
A six-inch cotton-tipped applicator or similar instrument can be used to search for focal intense pain generated by pressure applied behind the pterygoid hamulus on the affected side. Once the focal painful spot is located, then ¼ to ½ cc of local anesthetic can be deposited at the bony surface of the medial pterygoid plate. Aspiration and proper location of needle tip is necessary. If pain is remitted from the local anesthetic infiltration, then a follow-up injection of an anti-inflammatory medication may be utilized with success expected in about 90% of cases. Those cases that are refractory to medicine can be treated with focal radiofrequency thermoneurolysis.
Since the early 1980’s, Drs. Farrar and McCarty, Ernest, Anika Isberg, Noshir Mehta,4,5 Rocabado,6 and others have demonstrated that changes in the temporomandibular joint can influence the muscles of mastication, pharynx, ligaments, hyoid musculature, otic muscles, cervical axial muscles, and discs and facets of the neck. The dynamics of pain and or degenerative changes may flow from the TMJ area to the cervical muscles and spine or, in the reverse path, from the cervical spine to the temporomandibular joint and sometimes the dental occlusion. This degenerative process—representing the later stage of postural dynamic influences—suggests a need for greater understanding of the related structural regions.
The painful symptoms of this condition include:
This paper also serves to demonstrate the influence of the ligamento-muscular neural reflex arc loop in joint stability. Trauma, sprains, and degenerative changes that may affect joints and their respective muscles and ligaments are all factors that may play a role in the patients’ suffering of focal painful injuries. Of course, not all head and neck pain is a sprain or degenerative injury. But these injuries are very common and should not be presumed to be migraine, neuralgia, or tumor until otherwise ruled out.
The author would like to express his appreciation to Dr. David Trotter for photography.