Morphological study of styloid process of the temporal bone and its clinical implications

Abstract

The objective of this study was to study the morphometry of the styloid process of temporal bone and prevalence of elongated styloid process. The morphology of elongated styloid process along with its embryological and clinical importance are discussed. The present study included 110 human dry skulls which were procured from the bone collections of the department of anatomy. The styloid process was observed macroscopically on both sides of all the skulls, the elongations if any were noted. All the styloids were measured for their length, thickness at different levels and interstyloid distance at various levels. Out of 110 specimens, only 5 skulls (4.5%) exhibited the elongated styloid process. Among them, 3 skulls (2.7%) had unilateral elongation and 2 skulls (1.8%) had bilateral elongation of the styloid process. The mean length of the styloid process was 17.8±9.3 mm and 18.2±5.6 mm for the right and left sides, respectively. The prevalence of elongated styloid process in the present study was 4.5%. The clinical anatomy of this congenital variant is important to the neurosurgeon and radiologist, while interpreting the computed tomogram and magnetic resonance image scans. The morphological knowledge of elongated styloid process is clinically important since the course of the vertebral artery may be distorted in such situations.

Eagle syndrome. A narrative review

“…1,8,9,32 However, other authors, in current studies, indicate that the length of the styloid is variable. 4,29,30,31 They agree that a styloid process exceeding 30mm should be considered elongated.…”

“…29,30,33,34,[36][37][38] It belongs to the temporal bone from its lower surface at the junction of the petrous and tympanic portions below the external auditory meatus and anterior to the mastoid process. 15,16,19,31 The styloid process is usually located between the internal and external carotid arteries 7,26,36 and allows the insertion of the stylopharyngeus, stylohyoid and styloglossus muscles, 9,24,30 and also of the stylomandibular ligaments.…”

“…1,9,25 It was first des-cribed by Watt W. Eagle in 1937, [28][29][30] who defines it as the relationship between the elongation of the styloid process and the calcification of the stylohyoid ligament resulting in pain related to the cranial and sensory nerves of the oropharynx, neck and ear. This syndrome has three historical periods: the first one began 364 years ago with the first report of ossification of the stylohyoid process reported by Marchetti in 1652.…”

“…Complex Syndrome, 25 Carotid Artery Syndrome, 1 Carotid style Syndrome, 9 Elongated and Ossified Styloid Process Syndrome 1,9,28 or Stylohyoid Neuralgia. 1,9,25 It was first des-cribed by Watt W. Eagle in 1937, [28][29][30] who defines it as the relationship between the elongation of the styloid process and the calcification of the stylohyoid ligament resulting in pain related to the cranial and sensory nerves of the oropharynx, neck and ear.…”

“…Pain is caused by the elongation of the styloid process and by the partial or total calcification of the stylohyoid ligament. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The group consisting of the styloid process and the stylohyoid ligament is called "stylohyoid complex", [16][17][18] which has its embryonic origin in the cartilage of the second pharyngeal arch or hyoid arch (Reichert's cartilage). [19][20][21][22][23][24] ES is part of musculoskeletal disorders related to the temporomandibular joint; masticatory and cervical muscles as well as associated structures.…”