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28 avril 2004
J of Trauma
1985; 25; 10; 1010-1012
Fractures of the styloid process and stylohyoid ligament: an uncommon injury
Scott J. McCorkell
Department of radiology, Riyadh, Saoudi Arabia
Fracture of an ossified stylohyoïd boneJ McGinnis
Bâillements et stomatologie


Variation in the size of the styloid process and the amount of ossification of the stylohyoid ligament has been known by anatomists for centuries. During the last 100 years there have been sporadic reports of clinical symptoms both before and after trauma (3, 4). The amount of trauma associated with fracture of the styloid process varies considerably in published reports. In patients with minimal trauma or when fracture is related to normal actions such as yawning (4), a high index of suspicion is helpful in making the diagnosis because the elongated styloid process may be difficult to image radiographically. Two cases are presented that display the variability of clinical setting, symptomatology, and methods of diagnosis.
Case 1. A 30-year-old female radiology technician reported she got up quickly from bed during the night, and felt weak shortly before falling. After the fall she complained of headache, neck pain, and difficulty swallowing. Skull and cervical spine X-rays were interpreted as negative but the pain was sufficient for her to remain hospitalized for 1 day. CT scan of the head, done because of persistent headache, was negative. Review of the cervical spine and skull X-rays showed a fracture of an elongated Ieft styloid process. This was visible only on one film (Fig. 1) of the anterior-posterior, lateral, and oblique series. The patient was discharged with a neck collar and analgesics and slowly improved with conservative therapy. No surgical excision of the bony fragment was considered necessary.
Case 2. A 28-year-old male was admitted to the emergency room shortly after a road traffic accident. Upon initial evaluation and resuscitation, the patient was unresponsive to pain, with fixed pupils of 8 mm and Cheyne-Stokes breathing. A 3 X 5 cm slightly ecchymotic area of swelling was seen in the left neck. No carotid artery abnormality was noted and no facial injuries were present. The mandible was intact. A CT scan of the head showed considerable brain edema and only a small subdural collection of blood. Scans were continued without angulation at 10-mm increments through the neck where a fracture of an ossified left stylohyoid ligament was seen with considerable soft-tissue swelling. This was confimed with standard radiographs. Despite intracranial pressure monitoring and intravenous barbiturate therapy, the patient tient died of brain injuries 2 days after the accident.
The styloid process and the stylohyoid ligament are derived from the second branchial arch. These structures are first formed in cartilage. The cartilage of the styloid process ossifies while the epihyal cartilage, which connects the styloid process and the hyoid bone, is usually reabsorbed. The stylohyoid ligament is formed from the remnants of the epihyal cartilage (2). In some individuals, a separate epihyal bone forms when the epihyal cartilage ossifies rather than reabsorbs. Porrath (6) theorized that an ossified stylohyoid ligament occurs as a result of true ossification, rather than calcification due to stress or degeneration, because there is radiographic evidence of ossified stylohyoid ligaments in children.
The styloid process may vary from 5 to 50 mm in length and the stylohyoid ligament may ossify from its origin at the styloid process to its attachment at the hyoid bone (1). Variations in these structures were first reported in 1652 by Marchettis (3).
The styloid process serves as the origin of some of the muscles and ligaments concerned with deglutition and phonation and connects the hyoid bone through the stylohyoid ligament to the base of the skull. This may account for reports of fracture related to yawning or gagging.
Fracture of an elongated styloid process or ossified stylohyoid ligament may result in symptoms of neck swelling, pain in the throat, limitation of movement, hoarseness, dysphagia, or sensation of a foreign body (3, 4). Occasionally, patients may present with similar symptoms without fracture. McGinnis (4) described one man with a tender mass in the right neck. An ossified stylohyoid ligament was seen on X-ray. Several days later, while yawning, the patient felt the ligament fracture and the mass became acutely painful. X-rays documented the fracture and following resection of the inferior portion of the fractured ligament the patient had no further symptoms. Chandler (1) described four patients with previous head and neck carcinoma who were clinically thought to have recurrence of their tumor but radiographie evaluation showed the physical findings and symptoms were related to variations in the styloid process and ossification of the stylohyoid ligament. Hilding (3) reported a fracture of an elongated styloid process that occurred when a young man choked on a piece of meat, but more commonly the fracture is due to blunt trauma from automobile accidents. Reports of this injury have not mentioned respiratory difficulty, unlike reports of fracture of the hyoid bone in which asphyxia is a major concern (6). Although Case 2 had considerable swelling in the hypopharynx, it was not possible to separate respiratory difficulty caused by the massive head injury from that caused by the fracture of the ossified stylohyoid ligament. Hyoid bone fracture is also associated with fracture of the mandible, which has not been reported with styloid process fractures (5).
The clinical diagnosis of styloid process or stylohyoid ligament fracture can be substantiated with anteriorposterior, lateral, and oblique X-rays. Informing the radiologist of the suspected diagnosis caii be helpful because the mandible, cervical spine, and occipital bone all
may obscure the styloid process. Polytomography is probably not helpful because of the oblique course of the stylohyoid apparatus, but spot filming with fluoroscopy can separate overlying structures. Panorex tomography, if available, may provide good images. Computed tomography can be useful in comatose patients who are difficult to position for oblique films and who will probably be examined by CT for head injury as in Case 2. Scans should be done without gantry angulation at increments of 5 to 10 mm from the base of the skull through the hyoid bone. Extending the CT examination to include this area will not prolong the scan significantly and may add valuable information about the cervical spine and soft tissues of the neck.
Treatment of styloid process and stylohyoid ligament fractures has varied from conservative therapy with a neck collar and analgesia to surgical resection (4).
Prior knowledge of the clinical symptoms of stylohyoid ligament and styloid process fractures may make the diagnosis easier by expediting radiography, avoiding false diagnosis of foreign body (3), and avoiding direct laryngoscopy or biopsy.
  1. Chandler, S. R. Anatomic variations of the stylohyoid complex and their clinical significance Laryngscope 87: 1692-1701, 1977.
  2. Goodman, R. S. Fracture of an ossified stylohyoid ligament Arch. Otolaryngol 107:129-130,1981.
  3. Hilding, D. A. Fractures of an elongated styloid process masquerading as a foreign body. Ann. Otol Rhinol Laryngol 70: 689692,1961.
  4. McGinnis, J. M. Fractures of an ossified stylohyoid bone. Arch. Otolaryngol 107:460,1981.
  5. Papavaliliou, C. G., Speas, C. J. Fracture of the hyoid bone. Radiology, 72: 872--874, 1959.
  6. Porrath, S.Roentgenologic considerations of the hyoid apparatus. AJR 105: 63-73,1969.
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