Pterygospinous Bar and Foramen in the Adult Human Skulls of North India: Its Incidence and Clinical Relevance

Study of skulls has attracted the attention of anatomists since ages and sporadic attempts have been made to study skulls from time to time. Talking about the pterygoid processes of sphenoid bone, the irregular posterior border of lateral pterygoid plate usually presents, towards its upper part, a pterygospinous process, from which the pterygospinous ligament extends backwards and laterally to the spine of sphenoid. This ligament sometimes gets ossified as pterygospinous bar and a foramen is then formed, named pterygospinous foramen, for the passage of muscular branches of mandibular nerve. The present study was undertaken to observe the incidence and status of pterygospinous bony bridge and foramen, its variations, and clinical relevance in the adult human skulls of North India. For this purpose, 500 skulls were observed, belonging to the Anthropology Museum of Department of Anatomy, GSVM Medical College, Kanpur. Pterygospinous bars were found to be present in 51 skulls (10.2%), out of which completely ossified pterygospinous bony bridges were present in 20 skulls (4%) while 31 skulls (6.2%) had incompletely ossified pterygospinous ligaments. Such variations are of clinical significance for radiologists, neurologists, maxillofacial and dental surgeons, and anaesthetists, too.

Civinini bar: incidence in North Indians and its clinical relevance

Background and aim: Ossified pterygospinous ligament is a major cause of the entrapment of the lingual nerve or a branch of the mandibular nerve and may cause mandibular neuralgia. It can also constitute an obstacle for the mandibular nerve block which is a preferred method for pain relief especially for the fractures of mandible or cancer patients. Systematic study of these bars in North Indian population is lacking. Therefore this study was carried out to see the incidence of ossified pterygospinous bars in North Indian population. Materials and methods : The present study was an attempt to find out the occurrence of ossified pterygospinous ligament (Civinini's bar) in 116 dried skulls of unknown sex were taken and the presence of ossified pterygospinous bar was noted. Results : It was observed that the ossified pterygospinous bars which is present between pterygospinous process of lateral pterygoid plate and spine of sphenoid also called as Civinini's bar can be divided into five types (Types I, II, III, IV, V). This bar encloses a foramen called as Civinini's foramen. A total incidence of 18.10% of various types of pterygospinous bars was observed, out of which 1.72% were Type I, 8.62%Type II, 3.45%Type III, 0% Type IV and 4.31 % were of Type V variety. Conclusion : Total prevalence of Civinini bar is 18.10% in North Indian population.The clinicians working on this area should be aware of this variation as its prevalence is quite high.

Ossification of Ligaments Near the Foramen Ovale: An Anatomic Study With Potential Clinical Significance Regarding Transcutaneous Approaches to the Skull Base

Objective: There is paucity of information regarding the specific anatomy and clinical significance of ossified ligaments near the foramen ovale (e.g., pterygospinous and pterygoalar ligaments). The present study was undertaken to define this anatomy in more detail and to review the literature regarding these anatomic variations. Methods: One hundred fifty-four adult human dry skulls were analyzed for the presence of ossified ligaments of pterygospinous (ligament of Civinini) and pterygoalar (ligament of Hyrtl). Measurements were made of these bony structures and observations made of their relationships to the inferior aspect of the foramen ovale and neighboring structures. Results: Two ossifications each (2.6%) of the ligaments of Civinini and Hyrtl were found. One of each of these (1.3%) was completely ossified, thereby resulting in 2 complete foramina (i.e., 1 foramen of Civinini and 1 foramen of Hyrtl). A significant correlation was found between the left and right sides, with either complete or incomplete ossification of these ligaments being found on left sides (75%) (incomplete Civinini on right side and all others on left side). The complete foramen of Civinini was found to have an area of 16.7 mm2, and the complete foramen of Hyrtl was found to have an area of 9.42 mm2. Conclusion: Such anomalous bony obstructions could interfere with transcutaneous needle placement into the foramen ovale or distort anatomic relationships during approaches to the cranial base.