Superior Pharyngeal Constrictor Muscle Pain
A painful syndrome originating in the oral pharynx is described in this article. The symptoms, similar to those associated with Ernest Syndrome (stylomandibular ligament hyperextension injury), were documented at the Ernest Clinic in 1988. A review of symptomatic cases reveals the onset of pain with motor vehicle trauma and other trauma related events. The injury may be unilateral or bilateral in nature, and can result in limited mandibular opening due to the loss of muscle functionality resulting from the injury. Local anesthetic infiltration, in small volume, is the test method of choice and remission of pain is the indicator of the origin fibers’ involvement in the production of the painful symptoms. Cases that continue to hurt following the anesthetic benefit may be treated very selectively with radio-frequency thermo-neurolysis or radio-frequency pulse. It is our experience that the inclusion of the injured mandibular origin fibers of the superior pharyngeal constrictor muscle at mandible (SPCM-M) in the differential diagnosis of symptoms — that would otherwise suggest Ernest Syndrome may — serve to increase the degree of successful diagnosis and treatment.
Anatomy and Function
Gray1 describes the origin fibers of the superior pharyngeal constrictor muscle at mandible (SPCM-M) to be found at the lingual surface of the mandible (see Figure 1). The site of attachment is at, or below, the convexity of the mandibular lingual crest above a point called the mylohyoid line and medial to the third molar tooth. The muscle fibers serve to anchor and stabilize the wall of the superior pharynx in respiration, phonation, and narrows the pharynx in deglutition.
The pharyngeal branches of the vagus nerve, known as the tenth cranial nerve, provide innervation via the pharyngeal plexus. The only pharyngeal muscle not supplied by the Vagus is the Stylopharyngeus muscle.
The causes of injury to the origin fibers may be trauma, motor vehicular accident, third molar surgery, or other traumatic events. One patient had an oral impression event as the contributing factor to her painful episode. She experienced temporal tendinitis and SPCM-M pain from the strain of mouth opening. Our opinion is that this patient experienced some hyperextension of the mandible or lower jaw in the process of opening for dental impressions, and some possible trauma from the impression tray. She did resolve with an injection of local anesthetic and cortisone at the SPCM-M origin and temporal tendon insertion, and did not require any further treatment.
Syndrome Signs and Symptoms
- Palpable area of soreness at mandible where origin fibers of the superior constrictor muscle originates.
- May have difficulty in opening the mouth due to restraining action of the injured muscle fibers.
Symptoms on Same Side
- Lateral throat pain and or soreness
- Lower molar teeth hurt and ache
- Region of the insertion of the stylomandibular ligament is often sore and painful
- Ear pain and pressure
- Lateral temple pain
- TMJ pain and soreness
The best test to determine if there is an injury to the origin fibers of the SPCM-M is first the application of pressure (see Figure 2) to the suspected site, with the tongue retracted to the opposite side. If pressure stimulates pain at the muscle origin site and the referral sites, then inject one-eighth to one-quarter cc of local anesthetic into the tissue, being careful to observe if the Lingual nerve is unintentionally anesthetized. If remission of pain occurs—including the referral pattern—while anesthetized, then inject one-eighth cc of cortisone at the site. If the pain later reoccurs, then repeat the injection procedure 2 or 3 times over a 2 or 3 week period. Refractory cases should be considered for radio-frequency thermo-neurolysis or radio-frequency pulse, depending on the proximity of the lingual nerve. Please note that the lingual nerve is the sensory nerve to the tongue and must not be injured or compromised by treatment. For the clinician to create iatrogenesis in this area of the human body is not without unfortunate consequence for patient and doctor.
This article describes a pain syndrome that mimics Ernest Syndrome,2-12 and affects the head and neck region. To our knowledge, this syndrome is previously unreported in the literature, with the exception of an abstract of this article recently presented at the American Academy of Craniofacial Pain, 22nd Annual International Clinical Symposium, July 27-29, 2006, in Denver Colorado.
The constellation of symptoms may appear to suggest Ernest Syndrome to the unsuspecting clinician. The unfortunate result of that error is obvious to all who have attempted to treat what was thought to be Ernest Syndrome but failed to remit the painful symptoms. Effective treatment of SPCM-M Syndrome is usually very effective utilizing local anesthetic and cortisone. If the condition is refractory to non-surgical care, then a Radio-Frequency Thermo-Neurolysis (RFTN) or Radio-Frequency Pulse (RFP) unit can be used for treatment.
It is important to note these injuries are not trigger points nor or they neuralgias. This emphasis is added to avoid confusing clinicians who are still unfamiliar with origin and insertion attachment injuries of tendons and ligaments.