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International Journal of Morphology

versión On-line ISSN 0717-9502

Int. J. Morphol. vol.30 no.2 Temuco jun. 2012 

Int. J. Morphol., 30(2):701-704, 2012.


Anatomical, Clinical and Radiographic Characteristics of Styloid Syndrome (Eagle Syndrome): a Case Report


Características Anatómicas, Clínicas y Radiográficas del Síndrome Estiloide (Síndrome de Eagle): un Caso Clínico


*Rogério Leone Buchaim; **Daniela Vieira Buchaim; *André Luis Shinohara; *Antonio de Castro Rodrigues; *Jesus Carlos Andreo & * Farooque Jamaluddin Ahmed

* Department of Biological Sciences (Anatomy), Bauru School of Dentistry, University of São Paulo (FOB/USP, Bauru-SP, Brazil).

** University of Marília, Marília, SP, Brazil.

Correspondence to:

SUMMARY: Styloid syndrome is characterized by an elongated styloid process or calcification of the stylomandibular and stylohyoid ligament. This study describes a case of a 65-year-old woman who presented to the Stomatology Clinic, University of Marilia with temporomandibular joint pain, ear ringing and a reduced ability to open the mouth. Panoramic and posteroanterior digital radiographs showed bilateral elongation of the styloid processes, especially of the right side, whose length extended beyond the mandible angle. The diagnosis was confirmed with the association of clinical data and image examinations. The treatment options for styloid Syndrome include clinical follow-up, surgical removal of the styloid process or fracture of the elongated process. The case was managed by providing prosthetic rehabilitation and clinical follow-up, observing the level of discomfort and the benefit that could be achieved by the therapy, and avoiding surgical intervention.

KEY WORDS: Eagle syndrome; Elongated styloid process syndrome; Temporal bone.

RESUMEN: El síndrome estilode (Síndrome de Eagle) se caracteriza por un proceso estiloides alargado o calcificación de los ligamentos estilohioideo y estilomandibular. Este estudio describe el caso de una mujer de 65 años de edad que concurrió a la Clínica Estomatológica de la Universidad de Marilia con dolor de la articulación temporomandibular, zumbido en los oídos y una disminución de la capacidad de abrir la boca. Las radiografías digitales panorámica y posteroanterior mostraron alargamiento bilateral de los procesos estiloides, especialmente del lado derecho, cuya longitud se extendió más allá del ángulo de la mandíbula. El diagnóstico se confirmó con la asociación de los datos clínicos y los exámenes de imagen. Las opciones de tratamiento para el síndrome estiloide incluyen el seguimiento clínico, la extirpación quirúrgica del proceso estiloides o la fractura del proceso alargado. El caso fue tratado con rehabilitación protésica y seguimiento clínico, observando el nivel de molestia y el beneficio que se podría lograr mediante la terapia, evitando la intervención quirúrgica.

PALABRAS CLAVE: Síndrome de Eagle; Síndrome del proceso estiloides alargado; Hueso temporal.



The styloid process, located anterior to the stylomastoid foramen, originates in the second brachial arch, namely from the proximal surface of the Reichert's cartilage. It is a slender cylindrical bony projection, with a sharp end and of variable length that projects downward and forward from the inferior surface of the petrous part of the temporal bone, and is attached to the lesser cornu of the hyoid bone by the styloid-hyoid ligament. The temporal bone, easily observed on the side view of the skull, consists of five parts: squamous, tympanic, petrous, mastoid and styloid. Therefore, the styloid process was described as an anatomical accident of the external surface of the skull, on the petrous part of the temporal bone. This process provides attachment to three muscles: styloglossus, stylopharyngeus and stylohyoid and also to the stylomandibular ligament (Gray, 1988).

In addition to the aforementioned description, it should be noted that the styloid process is located between the internal and external carotid arteries, divisions of the common carotid artery, located in the anterior triangle of the neck.

The normal length of the styloid process is of approximately 25mm, as described by Eagle (1937), hence any length exceeding that size would be considered elongated. However, some authors consider the styloid process elongated if the length is more than 30 mm. Studies performed by anatomists have proven that 2% to 4% of the overall population have either an elongated or a calcified styloid process (Keur et al., 1986; Milner et al., 1996).

The main symptoms of classic styloid syndrome include: reduced ability to open the mouth, increased salivation, a foreign-body sensation and pain in the pharynx, and tinnitus. However, an elongated styloid process (Fig. 1) or calcified styloid ligament usually does not cause characteristic symptoms (Guo et al., 1997).

The etiology of this syndrome remains unknown, but many authors describe the involvement of traumas, such as tonsillectomy, which generally affects women between their 20's and 30's (Neville et al., 2009).

Styloid syndrome, also referred to as stylohyoid syndrome, is supposedly caused by the ossification of traces of cartilage in the stylohyoid complex, which may or may not present symptoms and is detected through clinical and radiographic examinations (Slavin, 2002).

Therefore, according to the literature review, the images most commonly used for diagnosis are the lateral and posteroanterior views of the skull, oblique and lateral views of the mandible, and panoramic radiographs (Stafne & Hollinshead, 1962).

The treatment options for styloid syndrome include clinical follow-up, in cases with mild symptoms and the surgical removal of the styloid process in more severe cases, which can be performed through intraoral or extraoral access (Bafaqeeh, 2000).

Fig. 1. Dry skull with bilateral elongated styloid processes (arrows).



A female leucodermic patient, 65 years of age, approached the Stomatology Clinic, University of Marilia with complaints of temporomandibular joint pain, auditory symptoms such as tinnitus, and a reduced ability to open the mouth. Her physical examination showed no apparent surface abnormalities. In the clinical examination of the mouth it was observed that some of the patient's teeth were missing in the upper and lower arches, and she wore an unsatisfactory removable partial denture on both arches. Digital panoramic and posteroanterior skull radiographs were obtained to make a probable diagnosis (Figs. 2 and 3). The radiographic evaluations showed a bilateral elongation of the styloid processes, especially on the right side, which was longer and segmented. Both elongated sides extended down the mandible angle. Thus, together with the help of observed clinical findings and the radiographic examinations, styloid syndrome (elongation of the styloid process) was proposed as the diagnosis. The management adopted in this case was indication of prosthetic rehabilitation with new partial removable dentures for both arches, without the need for surgery, considering the patient's age, the low-complexity of the symptoms, and the report for type 2 diabetes mellitus and arterial hypertension on her anamnesis.

The symptoms usually involve a limited ability to open the mouth, increased salivation, a foreign-body sensation, and tinnitus. Nevertheless, most patients with radiographic evidence of an elongated sytloid process or ligament ossification do not show any characteristic symptoms, and many symptomatic patients also do not have any trauma history (e.g. tonsillectomy) (Lira et al., 2005).

The elongated styloid process can be observed through radiographic examinations, such as lateral and posteroanterior skull radiographs, but Alvares & Tavano (2002) and Whaites (2009) defined that the panoramic radiograph is the most commonly used radiographic exam for diagnosing the syndrome, because it is an easy, low-radiation examination. Furthermore, in confirmed cases in which the recommended treatment involves surgery, tomography can be used as the radiological examination.

The diagnosis for styloid syndrome consists of an association between the clinical history, physical examination and complementary examinations. The treatment should be decided taking the particularities of each case into consideration, patients with mild symptoms should receive a conservative treatment while severe cases should consider having surgical interventions (Baugh & Stocks, 1993; Bafaqeeh).

Styloid syndrome is a rare condition, which can be diagnosed by associating clinical information and radiographic examinations together. Its treatment success depends on making a correct diagnosis and considering the symptoms to choose between a conservative or surgical treatment. In this particular case, the patient achieved relief through symptomatic treatment, prosthetic rehabilitation and subsequent clinical follow up without the need of any surgical intervention.

Fig. 2. Plain arrows indicate the bilaterally elongated styloid process and the dotted arrow indicates the segmentation on the right side.

Fig. 3. Arrows indicate an elongated styloid process in the posteroanterior radiograph.



The normal size of the sytloid process can vary considerably, with reports in the literature stating lengths from 15 mm to 40 mm. However, in 1937 Eagle described that styloid processes with lengths of over 25 mm should be considered elongated. Cadaver studies show that 2% to 4% of the overall population has an elongated styloid process or calcified styloid ligament (Keur et al.; Murtagh et al., 2001).

Guo et al. observed that unilateral ossification of the styloid ligament is the most frequent. Leite et al. (1988) on the other hand, reported that there is no predominance of unilateral over bilateral ossification, as there was no significant difference between the studied skulls.

As to the prevalence in the overall population, Grossman & Tarsitano (1977) reported that the syndrome usually affects adults, with no difference between sexes. However, Neville et al. observed that the syndrome affects mostly women in their 20s and 30s.


ACKNOWLEDGEMENTS. The authors would like to thank the Department of Basic Sciences, Anatomy discipline, School of Dentistry (Unesp/Araçatuba-SP/Brazil).



Alvares, L. C. & Tavano, O. Curso de Radiologia em Odontologia. 4ta Ed. São Paulo, Santos, 2002. p.248.

Bafaqeeh, S. A. Eagle syndrome: classic and carotid artery types. J. Otolaryngol., 29(2):88-94, 2000.

Baugh, R. F. & Stocks, R. M. Eagle's syndrome: a reappraisal. Ear Nose Throat J., 72(5):341-4, 1993.

Eagle, W. W. Enlongated styloid process: Report of two cases. Arch. Otolaryngol., 25(5):584-7, 1937.

Grossman, J. R. & Tarsitano, J. J. The styloid-stylohyoid syndrome. J. Oral Surg., 35(7):555-60, 1977.

Gray, H. Anatomia. 29a Ed. Rio de Janeiro, Guanabara Koogan, 1988. p.1147.

Guo, B.; Jaovisidha, S.; Sartoris, D. J.; Ryu, K. N.; Berthiaume, M. J.; Clopton, P.; Brossman, J. & Resnick, D. Correlation between ossification of the stylohyoid ligament and osteophytes of the cervical spine. J. Rheumatol., 24(8):1575-81, 1997.

Keur, J. J.; Campbel, J. P.; McCarthy, J. F. & Ralph, W. J. The clinical significance of the elongated styloid process. Oral Surg. Oral Med. Oral Pathol., 61(4):399-404, 1986.

Leite, H. F.; Niccoli Filho, W. D.; Liberti, E. A.; Madeira, M. C. & Simões, S. Prevalência do processo estilóde alongado em crânios humanos. Rev. Odontol. Unesp., 17(1):145-51, 1988.

Lira, M. M.; França, D. C. C.; Trento, C. L.; Tiano, G. C. & Castro, A. L. Síndrome de eagle: Relato de caso Clínico. Rev. Odontol. UNESP, 26(1):32-5, 2005.

Milner, E.; Donato, A. C.; Fregonesi, M.; Mistro, F. Z.; Moreira, C. A.; Kignel, S. & Fregonesi, F. Síndrome de Eagle-apresentação de 3 casos clínicos e revisão da literatura. Rev. Paul. Odontol., 18(6):26-8, 1996.

Murtagh, R. D.; Caracciolo, J. T. & Fernandez, G. CT findings associated with Eagle syndrome. Am. J. Neuroradiol., 22(7):1401-2, 2001.

Neville, B.; Dam, D. D.; Allen, C. M. & Bouquot, J. Patologia oral e maxilofacial. 3a Ed. Rio de Janeiro, Elsevier, 2009. p.972.

Slavin, K. V. Eagle syndrome: entrapment of the glossopharyngeal nerve? Case report and review of the literature. J. Neurosurg., 97(1):216-8, 2002.

Stafne, E. C. & Hollinshead, W. H. Roengenographic observations on the styloyoid chain. Oral Surg. Oral Med. Oral Pathol., 15(5):1195-200, 1962.

Whaites, E. Princípios de radiologia odontológica. 4a Ed. Rio de Janeiro, Elsevier, 2009. p.424.

Correspondence to:

Rogério Leone Buchaim

University of São Paulo
School of Dentistry of Bauru
Department of Biological Science
Al. Octávio Pinheiro Brisola, 9-75
Bauru, SP, Cep: 17.012-901
Phone: +55 14 32358220
Fax: +55 14 32358334


Received: 30-11-2011
Accepted: 27-02-2012

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