Hamular Process Bursitis

Often misdiagnosed as otitis media or Eagle’s syndrome, this relatively unknown disorder presents as soft palate pain, throat pain, ipsilateral maxillary pain, ear pain and difficulty and pain with swallowing.
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In this article, Dr. Shankland describes an important subject that is both under-recognized and clinically relevant. As an anatomist and a dentist, he has had a significant impact in the field of facial pain as a result of his anatomical research. I believe his description and documentation of the Zygomandibularis muscle and Hamular Bursitis has added another significant link in solving orofacial pain, as will be seen in this article. Hopefully the paper will also stimulate memories of prior patients who may have suffered the symptoms listed for Hamular Bursitis, but were unrecognized at the time of exam.

Edwin A. Ernest, III, DMD, FAANaOS

Throat pain is a difficult problem to diagnose and crosses the boundaries of many specialties: otolaryngology, dentistry, and internal medicine, just to name a few. Pain emanating from this area has been discussed in the literature for more than a century.1-4 The diagnostician must consider the embryological development and migration of the branchial arches, both of which produce the immense anatomical complexity of the throat and associated structures. Until recently, throat pain was generally felt to be caused by styloid syndromes.1-4 Ernest5 discovered one such disorder that now bears his name—namely, Ernest Syndrome—which has subsequently been described by others.6,7 However, several authors have discussed an additional and little known disorder which has been associated with elongation,8 swelling,9 and pain10-13 of the pterygoid hamulus of the sphenoid bone. Specifically, the chief cause of pain of the hamular process appears to be inflammation or bursitis of the synovial bursa of the process.10,14,15

Anatomy

The sphenoid bone is a midline bony structure lying anterior to the basilar portion of the occipital bone, protected on either side by the temporal bones. The sphenoid has a central body, paired greater and lesser wings spreading laterally from it, and two pterygoid processes descending from the junctions of the body and the greater wings. The pterygoid plates arise laterally and medially from the inferior surface of the side of the body and from the root of the greater wings and pass vertically downwards. The lateral and medial pterygoid plates diverge inferiorly and between them is formed an ovoid fossa, the pterygoid or scaphoid fossa. This area contains the medial pterygoid and tensor veli palatini muscles.

The medial pterygoid plate is narrower and longer than the lateral plate. Originating from the body and greater wing of the sphenoid, the medial pterygoid plate descends in an inferior and slightly lateral direction. The lower end of the posterior border of the medial plate appears to be continued as a slender, curved or hook-like process termed the pterygoid hamulus (see Figure 1).

Figure 1. Dry skull demonstrating pterygoid hamulus, viewed from the lateral. Legend: LPP. Lateral pterygoid plate; HP. Hamular process of the medial pterygoid plate of the sphenoid bone.

The hamulus and the edge of the medial pterygoid plate immediately superior to the hamulus give rise to the origin of the superior constrictor muscle of the pharynx; below the hamulus these fibers merge with those of the buccinator muscle to form the pterygomandibular raphe.16,17 This raphe connects the hamulus to the mylohyoid line of the mandible at, or near, the most posterior molar tooth.18 In addition, the palatopharyngeus muscle originates from the hamular process, as well as from the border of the hard palate, the lower surface of the palatal aponeurosis, and from fibers of the levator veli palatini muscle.19 The tensor veli palatini muscle, originating from the scaphoid fossa, the spine of the palatal aponeurosis, and the lateral wall of the cartilaginous auditory tube, winds its tendon around the hamular process in a groove and inserts into the soft palate and the transverse bony ridge on the posterior border of the horizontal plate of the palatine bone or the palatal aponeurosis. As the tendon of the tensor veli palatini winds around the hamulus, a synovial bursa is situated between the tendon and the bone (see Figure 2).

Figure 2. Pterygoid hamulus viewed from the rear. Legend: e. bursa; f. tensor veli palatine; g. levator veli palatine; h. tendon of the tensor veli palatine; j. styloid process. (From: Shankland WE. Pterygoid hamulus bursitis: one cause of craniofacial pain. J Prosthet Dent.4 Used with permission.)

Synovial bursae exist where moving structures are in tight apposition, especially where tendons are deflected around bone.20 In the case of this bursa, its primary function is to reduce friction due to movement of the tendon of the tensor veli palatini muscle around the pterygoid hamulus. The tendinous band of the muscle passes through the bursa, which is actually a closed synovial tendon sheath.4,21

Symptoms

There are several symptoms of inflammation of the bursa of the hamular process which include:

  • Pain in the hamular region of the palate;
  • Palatal pain;
  • Ipsilateral throat pain;
  • Ipsilateral maxillary pain;
  • Difficulty and pain with swallowing;
  • Ear pain; and
  • Localized erythema over the hamular region.

Virtually every one suffering this bursitis will report a history of the seeing numerous physicians to discover the cause of their symptoms. Frequently, they will be wearing a maxillary denture, which is worn only for esthetic reasons, if worn at all. Trauma from swallowing a large bolus of food, an over-extended denture, or striking the hamulus while brushing the maxillary posterior teeth all seem to be reasonable theoretical causes which could produce bursitis of the pterygoid hamulus bursa. Some of these patients have been victims of forced fellatio and may require psychological counseling. In addition, some individuals simply have more prominent hamuli22 which are more susceptible to mechanical trauma.

Diagnosis

One should base the diagnosis on the reported history, physical examination, and the success of an anesthetic infiltration into the hamular region. Physically, due to the vascularity of the soft palate, the hamular region often appears erythematous normally directly over the hamular process. However, in the case of bursitis, the offending side will be significantly redder than the opposite side. Also, elongated hamuli will be evident as a firm swelling or enlargement under the mucosa of the soft palate. In addition, the hamulus will be tender to palpation and this tenderness will be eliminated after anesthetic infiltration of the area. If the pain is eliminated while the region is anesthetized but returns after the anesthetic is metabolized, then consider a diagnosis of bursitis of the hamular process.

Obtain radiographs of the hamulus and pterygomaxillary region to determine if the hamulus is fractured, if an osteophyte is present on the hamular process, or for any other abnormal findings. The hamular process is visible on cephalometric radiographs.

Treatment

Treatment of bursitis of the hamular process is either palliative or surgical. For palliative or conservative treatment, remove the trauma or irritation (e.g., adjustment of the maxillary denture’s posterior border) and inject synthetic cortisone or Sarapin® (High Chemical) into the hamulus region. In addition, place the patient on anti-inflammatory medications and re-evaluate in 10 to 14 days. Repeat the therapeutic injections if necessary.

First published on: September 1, 2008