Unseen Until Death: Incidental Findings of Elongated Styloid Process in a Medico-legal Autopsy—Case Series

Bilateral Stylohyoid Syndrome: A Rare Cause of Cervical Pain

Elongated Styloid Process

A 30-year-old man without cardiovascular risk factors presented, after 1 week of right-sided anterior neck pain, with acute left hemiplegia immediately after heavy weight lifting (i.e., removing large boxes filled with books with the head in mid-position without rotation). There was no recent history of head or cervical trauma. Brain MRI showed an acute infarction in the right middle cerebral artery territory. Carotid duplex examination revealed a high degree of stenosis of the right internal carotid artery, which was confirmed by CT angiography showing a segmental tapered narrowing of the right internal carotid artery located just lateral of the greater horn of hyoid bone, in the absence of atheromatous plaques (Fig. 1). Fat-saturated T1 MRI showed the presence of an intramural hematoma in the right internal carotid artery. A diagnosis of carotid dissection, in absence of clear head/ cervical trauma was made, and anticoagulation treatment was started. CT angiography also showed a 90-mm-long bilateral elongated styloid process (Fig. 1). However, the tip of the elongated styloid process was located at 9.1 mm of the right internal carotid artery, and the smallest distance between the body of the elongated styloid process and the right internal carotid artery was 3.5 mm, making impingement of the carotid artery by the styloid process, even with head rotation or flexion, unlikely. Another abnormality was noticed on CT angiography, consisting of an elongated hyoid bone resulting in a extremely reduced distance of 1.6 mm between the anterior tubercle of the transverse process of the third cervical vertebra and the greater horn of the hyoid bone (Figs. 1, 2). Three months later, CT angiography revealed complete recanalization of the right internal carotid artery (with a diameter of 4.5 mm at the level of the greater horn of the hyoid bone), now located medial of the greater horn of the hyoid bone (Fig. 2). Carotid duplex examination showed normal velocities, in the absence of changes in velocities after head rotation. We hypothesized that intermittent change in position of the internal carotid artery (diameter 4.5 mm) through the small space (1.6 mm) between the third cervical vertebra and the hyoid bone may have provoked the arterial dissection, although carotid injury due to the elongated styloid bone could not be excluded. In a vast portion of patients with carotid dissection, there is no clear history of head or cervical trauma. The exact cause of these, so-called spontaneous, dissections is unclear. Recently, certain anatomic characteristics of the styloid process (i.e., the length and the proximity to the carotid artery) have been reported as potential risks factors for carotid dissection [1]. The stylohyoid complex consists of the styloid process, the stylohyoid ligament, and hyoid bone. Pathological conditions (called the stylohyoid complex syndrome) associated with these structures, which can include an elongated styloid process, ossified stylohyoid ligament, elongated hyoid bone, or combinations of several of these conditions (like in our patient with both elongated styloid process and elongated hyoid bone) can cause cervical and pharyngeal symptoms, probably related to irritation of the structures around this complex (including the carotid arteries and the cranial nerves VII, IX, and X) [2]. D. Renard (&) Department of Neurology, CHU Nimes, Hopital Caremeau, Place du Pr Debre, 30029 Nimes Cedex 4, France e-mail: dimitrirenard@hotmail.com

Although the roentgen ray affords the most informative single means of study of the hyoid apparatus, only two case reports were found in the radiologic literature concerning its anomalies (1, 3), both calling attention to anomalous ossification in the stylohyoid ligaments, with no mention of anomaly of the hyoid bone itself. Such reports as have appeared in the general medical literature deal almost entirely with anomalous long styloid processes and ossified stylohyoid ligaments, though Puchowski (4) reported a case in which there was anomalous ossification in the hyothyroid ligaments as well. Anomalous long styloid processes are said to be encountered in one of every 3,000 tonsillectomies (2). Forty-four cases of complete ossification of the stylohyoid ligaments have been reported. In the case to be recorded here, an anomalous hyoid bone was associated with elongated styloid processes and ossifications in the stylohyoid and hyothyroid ligaments. A search of the literature disclosed no similar example. Report of case A white male, 39 years of age, had suffered for the past twenty-five years from attacks of pain in the right side of the neck radiating to the external occipital protuberance. The attacks, lasting one or two days, occurred at intervals of three to six months. They were initiated by resting on the right side of the neck or by a sudden twist of the head to the right. Associated with the pain were moderate dysphagia and tenderness internally in the lateral pharyngeal wall and externally over the right half of the hyoid apparatus. Roentgen study showed the body of the hyoid bone to be about 50 per cent larger than usual (Fig. 2). The combined length of the styloid process and ossified stylohyoid ligament was 6.5 cm. bilaterally. The right greater cornu of the hyoid bone stood 1.5 cm. higher in the neck than the greater cornu on the left (Fig. 3) and consisted of a horizontal segment (0.6 × 4.0 cm.) and a vertical segment (1 × 3 cm.) inseparably fused into a 7-shaped bone. The vertical segment formed a conspicuous joint with a bone (1 × 1 cm.) replacing the right superior cornu of the thyroid cartilage. The distal centimeter of the left greater cornu of the hyoid bone (0.4 × 4.0 cm.) was angulated 40° downward, backward, and outward and approached to within 0.2 cm. of the backward, upward, and outward angulated superior cornu (0.4 × 1.5 cm.) of the thyroid cartilage (Figs. 1 and 2). Comment In man the hyoid bone is the only bone which normally forms no joint with other bones. It has a considerable range of up-ward, downward, backward, and forward mobility. When, however, the stylohyoid and/or hyothyroid ligaments are partially or completely ossified, the mobility of the hyoid bone is interfered with and the hyoid apparatus becomes less flexible, so that exceptional stresses may produce symptoms. In the case reported here, the styloid processes measured 3 cm. longer than normal.

A 26-year-old man who had end-stage renal disease (ESRD) due to primary glomerulonephritis presented for a routine dental examination. He had peritoneal dialysis (PD) as renal replacement therapy for 2 years. He had smoking one to two packs of cigarettes a day for five years and did not drink alcohol. On clinical examination, the maxillary left canine tooth was absent. The left first molar tooth’s clinical crown was fully carious, but its roots were in the jaw. In the mandibular jaw, the right first molar tooth and the left first molar tooth were carious. A panoramic radiography (PR) was taken as a screening film after the examination. Radiographic imaging showed that the left canine tooth was impacted, and the left first molar tooth’s roots were in the maxillary jaw. In the mandibular jaw, the left third molar tooth was also impacted and the right first molar tooth was carious, but the roots were in the jaw. Bilateral styloid process elongations (SPEs) were also detected (right: 47 mm, left: 58 mm) in the PR of the patient (Figure 1). He had any complaints regarding SPE or Eagle’s syndrome. Figure 1. Bileteral styloid process elongation in an end-stage renal disease patient with peritoneal dialysis on a panoramic radiography. The styloid process (SP) is a cylindrical, long cartilaginous bone located on the temporal bone. There are many vessels such as carotid arteries and nerves adjacent to the SP.1,2 The normal length of the SP is approximately 20–30 mm.3–8 The length of SP and/or stylohyoid ligament, which are longer than 30 mm were considered to be SPE.3,5,7–10 SPE resulted in facial and neck pain is known as Eagle’s syndrome.5,6,10,11 More uncommonly, symptoms such as dysphagia, tinnitus, and otalgia may occur in patients with this syndrome. The symptoms and signs with this syndrome are due to the anatomic relationship between the SP and its surrounding structures.1,12 Therefore, it may also cause stroke due to the compression of carotid arteries.3,13 The exact cause of the elongated SP due to calcified and ossified bone and the ligament is not clear. It was suggested that local chronic irritations, surgical trauma, endocrine disorders in female at menopause, persistence of mesenchymal elements, growth of the osseous tissue and mechanical stress or trauma during development of SP could result in calcified hyperplasia of the SP.3,10,14,15 Extraskeletal (ectopic) calcification or ossification may have a role for the elongation of the SP. Ectopic calcification (EC) in nonosseous soft tissue may be due to three mechanisms: metastatic calcification due to disorders causing abnormal serum Ca and P levels, dystrophic calcification due to mineral deposition into metabolically impaired or dead tissue despite normal serum levels of Ca and P, and ectopic ossification. The patients with ESRD have risks for EC due to disorders (renal failure, dialysis, secondary hyperparathyroidism) causing metastatic calcification.16 In the present report, a detailed differential diagnosis was done for the disorders causing dystrophic calcification (scleroderma, dermatomyositis, systemic lupus erythematosis, trauma-induced etc.), ectopic ossification (post surgery, burns, neurologic injury, myositis ossificans etc.) and also, any diseases causing metastatic calcification. Except renal failure, disease causing metastatic calcification such as sarcoidosis, tumoral calcinosis, primary hyperparathyroidism, milk alkali syndrome etc. were investigated for this patient and any disease was detected.16 As a result, SPE found as incidental findings on PRs may be important clinically in not only patients with ESRD, but also normal population. Instead of many hypotheses and studies, the exact etiology of elongated SP and the role of ectopic calcification are unknown. Abnormality in Ca and P metabolism (EC) is very common in patients with ESRD. According to our knowledge, this is the first case study showing SPE associated with ESRD in a patient. In conclusion, this report suggests that EC or the abnormality in Ca and P metabolism may have a role in the elongation of SP. However, further studies and large samples are needed to clarify the etiology of this disorder, and the role of EC.

Eagle's syndrome is most often associated with an elongated styloid process or ossified stylohyoid ligament, which may result in cervicofacial pain. Since the symptoms are vague and nonspecific, patients with the Eagle's syndrome are difficult to diagnose. We here report two cases of Eagle's syndrome, one case with unusually elongated styloid process of size 6.97 cm, in whom imaging with computed tomography established the diagnosis and managed by local infiltration of lidocaine and steroid; in another case the length of styloid processes were 3.47 cm and 3 cm respectively and was managed surgically.

Objective The Eagle syndrome is a rare condition. The highly heterogeneous symptom complex arises from an elongated styloid process or an ossified stylohyoid ligament. The causes of the pathological ossification processes are not fully understood. This study aimed to investigate the histological structure of enlarged styloid processes (SP) and ossified stylohyoid ligaments (SHL) in Eagle syndrome patients to understand their etiology and formation processes. Methods A 2-year retrospective study was conducted, analyzing bone samples from 22 Eagle syndrome patients diagnosed with either type I (enlarged SP) or type II (ossified SHL). Imaging, surgical planning, and histological investigations were performed to characterize the bone structures. Histological analysis focused on bone structure, bone apposition, styloid tips and ligaments, and intraosseous cartilage remnants. Covariates included patient demographics, surgical procedures, and anatomical variations observed during histological examination. Microscopic analyses were conducted on tissue samples using various staining techniques to evaluate bone structure, cartilage remnants, and signs of ossification. Results Histological examination revealed lamellar bone in both type I and type II cases, with differences observed in bone apposition and cartilage remnants. Subperiosteal bone apposition was more pronounced in type I cases, while cartilage remnants with enchondral ossification were found in both types. Conclusion Eagle syndrome comprises distinct types characterized by either enlarged SP or ossified SHL. Histological findings suggest that both types involve osteogenesis from fibrous cartilage tissues and cartilage remnants, contributing to bone tissue growth. Understanding these processes is crucial for effective diagnosis and management of Eagle syndrome.

Introduction: Eagle syndrome is a rare condition caused by elongation of the styloid process or ossification of the stylohyoid ligament. It’s named after Watt W. Eagle an otolaryngologist at Duke university, who described the first case in 1937. In the clinical presentation, we found different signs of syndrome – dysphagia, odynophagia, otalgia, foreign body sensation, facial pain, trismus, headache, increased salivation, and/or voice changes. The diagnosis of Eagle’s syndrome is based on an optimal medical history and physical examination. The most accurate imaging technique is the CT- scan. 3-D CT reconstruction of the neck specify the size of length of the styloid process (>3 mm) and the ossified stylohyoid ligament. The treatment includes conservative and surgical approach. Material and methods: We present a 65- years old female, in a good health condition, with the following complains: difficulty swallowing, foreign body sensation in the throat. The patient states that she had palpated cartilage in the right side in the area of the tonsillar fossa. The physical examination revealed no abnormal findings, but palpable right styloid process. We performed CT and 3-D CT reconstruction, which showed an elongation of styloid process on right side. Results: The patient refused the surgical treatment. The conservative therapy includes the nonsteroidal anti- inflammatory medications. Conclusion: Eagle’s syndrome is a rare condition with vast differential diagnosis, vague symptomatology and ambiguous incidence and etiology. When we suggest the syndrome, the CT scan is the imaging method of choice for diagnosis. It shows the measurement of styloid process, the position in the neurovascular complex and the prepositions of damages. The treatment can be surgical or non-surgical depend on the size, position and surgical risk of the approach

Variability of the styloid process and stylohyoid ligament in panoramic radiographs

Introduction: Styloid process (SP) is a bony projection present anteromedial to stylomastoid foramen, projecting downward from the inferior surface of the temporal bone. The normal length of SP ranges between 20 and 25 mm, elongated styloid process is also known as Eagle's syndrome, a rare condition that may irritates or disrupts adjacent anatomical structures. Objectives: To report a case of dry skull with elongated styloid process and to discuss possible risk of compression of neurovascular structures associated with it. Materials and Methods: Fifty three adult Human Dry Skull were measured for the following parameters using Digital Vernier Caliper in the Department of Anatomy, SRM Dental College, Chennai1. Length of SP2. Distance between the two Styloid processes at the base3. Distance between the two Styloid processes at the tip4. Thickness at the base of SP5. Distance between the SP and stylomastoid foramen. Results: Out of 53 adult dry skulls studied, one skull identified for bilateral elongated styloid process. The length of the right SP is 3.13 cm and of left is 3.17 cm. Thickness at the base of right SP was 5.6 cm, and the left was 4.7 cm. Distance between the two SPs at the base was measured as 6.93 cm whereas distance between the two SPs at the tip was found to be 5.64 cm. The distance between the SP and stylomastoid foramen on the right was 1 cm and on the left side was 1.2 cm. Conclusion: Although symptoms of Elongated styloid process (EPS) are well known in the literature, it is rarely on the forefront of the clinician's mind. Awareness of EPS and knowledge of the anatomy associated with it may help clinicians to differentiate from other Neurological conditions.

Elongated styloid processes (>30 mm), medial-lateral angulation, and calcification/ossification of the stylohyoid ligament are key factors to consider when diagnosing Eagle syndrome. This case, presented within a historical context, aims to provide data on the prevalence, morphological variations, and clinical significance of this condition over time, thereby bridging the fields of paleopathology and modern clinical practice. An adult male (identified as T.26) with bilateral elongation of the stylohyoid complex was analysed. Dated to the 6th7th centuries CE from the necropolis of Cabezo Del Molino, Rojales, Alicante, Spain. Computed tomography (CT) was employed to study the elongated styloid processes and their paleopathological implications. The tomographic images enabled the measurement of the length of both styloid processes, as well as the medial-lateral angle. In this case, both stylohyoid complexes exceeded 30 mm in length, exhibited medial thickening, and showed partial calcification/ossification of the stylohyoid ligament. This irregular attachment between the styloid process and the ligament, combined with medial-lateral angulation (MLA), may contribute to clinical symptoms such as loss of vision and stroke, and could even lead to arterial dissection. Medial-lateral angulation of the styloid process, rather than its length alone, should be considered a potential cause of pathological symptoms. It should be noted that preservation of styloid processes in osteoarchaeological contexts is rare, and it is even rarer when it involves the elongation of both stylohyoid complexes.

Ponticlus posticus (PP) as a one of the cervical vertebra variations brings about symptoms similar to Eagle syndrome. This study aimed to determine the relationship between elongated styloid process (ESP) and PP in a group of Iranian patients using cone-beam computed tomography (CBCT) images. The CBCT images of 349 patients (118 males and 231 females; mean age: 32.53 ± 14.143) were involved in this study. The atlas vertebra was investigated for the presence and classification of PP (partial or complete) in sagittal views. Also, the styloid process was evaluated for the presence of ESP in reconstructed panoramic and three-dimensional images. Data were analysed using Mann-Whitney test, Fisher's exact test, and Chi-square test to assess the relationship between the presence of PP and ESP with regard to age and gender. Ponticulus posticus was observed in 24.5% of patients with ESP and 31.98% of patients without ESP. There was no significant relationship between the presence of PP and ESP (p = 0.198). Twenty-five patients with ESP showed PP; cases of ESP with either side and opposite side PP were 7.84% and 1.96%, respectively. Cases of bilateral ESP and PP were predominant (14.70%). The mean age of patients with bilateral ESP and PP was higher than others. There was no significant difference between males and females (p = 0.456). Considering the prevalence and characteristics of PP in the case and control groups, there was no significant relationship between PP and ESP.

Elongated Styloid Processes and Calcified Stylohyoid Ligaments in a Patient With Neck Pain: Implications for Manual Therapy Practice

A case of styloid process syndrome with complete bilateral ossification of the stylohyoid ligament

Background: Styloid process (SP) is a slender pointed part of the temporal bone, which is closely related to the stylomastoid foramen. As many important neurovascular structures located near the tip of SP, the elongation or ossification of stylohyoid ligament may be associated with pain related to orofacial region known as Eagle’s syndrome. Aim of this study was to assess the prevalence of elongated SP, its morphology and calcification pattern on digital panoramic radiographs in patients attending the dental clinic of the University of Benghazi. Material and Methods: The digital panoramic radiographs with visible styloid processes of the studied group of patients were studied for their visibility, length and pattern of calcification. The length of styloid processes was measured in the radiograph and was considered elongated if that length exceeded 30 mm. The prevalence and pattern of elongation and calcification were determined according to Langlais classification. Results: Out of the 304 patients (164 are males and 140 are females) examined radiographically, the elongation of SP was detected in 156 (51.31%) of the patients. It was bilateral in 151 (96.79%) cases. There were no significant differences between males and females in regard to the length and shape of SP between in all age groups in both sexes, but the calcification pattern was significantly different between the age groups in both sexes. The outlined pattern of calcification of SP was the most prevalent especially in the younger age group (10-19 years), while the complete calcification pattern was most commonly detected in the older age group (≥ 60 years). Conclusion: elongated SP whether it is accompanied by pain symptoms or asymptomatic, can easily be detected on a digital panoramic radiograph and should be considered in the differential diagnosis of orofacial pain.