An Anatomical Study of Occurrence of Pterygospinous Bar in Indian Skulls

 

S.S. Shivanni1*, K. Yuvaraj Babu2

1I year BDS, Saveetha Dental College and Hospitals, Chennai.

2Assistant Professor, Department of Anatomy, Saveetha Dental College and Hospitals, Chennai.

*Corresponding Author E-mail:

 

ABSTRACT:

Background: Pterygospinous ligament is present at the base of the skull that may sometimes get ossified to form bony bars that are related to the foramen ovale.

Aim: This study aims at finding the prevalence of pterygospinous bar among Indian skulls present in Saveetha Dental College.

Method: The study was done in 40 adult human dry skulls from. The skulls were checked for the presence of pterygospinous bar and was analysed for the problems it might cause due to its presence.

Result: Among 40 skulls, pterygospinous bar is present only among 3 skulls which is 8% of the skulls.

Conclusion: Pterygospinous bar is present only in a small fraction of skulls. The foramen ovale is related to it and its presence may lead to the compression of the contents passing through the foramen.

 

KEYWORDS:

 

 


INTRODUCTION:

Sphenoid bone lies in the base of the skull, "wedged" between the frontal, temporal, and occipital bones. It has a central body, paired greater and lesser wings spreading laterally from it, and two pterygoid processes. Each of these processes, descending perpendicularly from the junctions of greater wings and body of sphenoid, consists of a medial and a lateral plate 1.The lateral pterygoid plate consists of anterior and posterior margins. The posterior free margin presents a small spur at the root or in the centre, which is called spine of civinini. Thickening of fascia between the lateral and medial pterygoid muscles leads to the formation of Pterygospinous ligament, which extends from the bony spur to spine of sphenoid.

The ligament may ossify or calcify to form pterygospinous bar. The ossification may be complete or incomplete. The complete ossification of the bar results in an individual foramen which is called Foramen of civinini. This foramen is completed by an upward continuation of the interpterygoid fascia or aponeurosis, which is called cribiform fascia. This fascia is pierced by accessory meningeal artery, nerve to medial pterygoid and tensor velli palatine muscle. Sometimes, pterygoid venous plexus may pass through the pterygospinous ligament 2.

 

Various ligaments present in the skull base are of clinical and surgical importance. Among them, the pterygospinous and pterygoalar ligaments are located close to the foramen ovale and maintain an important clinical relationship with this structure 3. Ossification of ligaments can lead to symptomatic compression of regional structures, especially nerves, and should be considered in patients in whom other causes for compressive syndrome cannot be identified. Ossification of ligaments of surgical base can also obstruct surgical corridors and interfere with operative access in this    area 4.

 

The presence of these bony bridges in children suggested the possibility of genetic factors 5. The presence of ossification in the pterygospinous and pterygoalar ligaments have clinical significance as these ligaments establish relationships with the oval foramen and because of the effects that emerge from it, such as increasing difficulty in accessing the oval foramen in a surgical approach 6.

 

MATERIALS AND METHODS:

Occurrence of ossified pterygospinous ligament were studied in 40 adult dry skulls of unknown origin and sex. The study was conducted in the Department of Anatomy, Saveetha Dental College and Hospitals. The number of ossified pterygospinous ligament were observed and noted. Broken and unclear skulls were not taken into consideration.

 

     

Figure 1 and 2 shows the presence of pterygospinous bar in skulls.

 

RESULT:

Among the 40 adult dry skulls, only 3 skulls were observed with the presence of pterygospinous bar while 37 skulls did not have pterygospinous bar. The pterygospinous bar is present in about 8% of the total skulls. This shows that the pterygospinous ligament is quite a rare sight of ossification.

 

 

 

Figure.3- Pie chart showing presence of pterygospinous bar.

 

DISCUSSION:

In a study by Mari Eli Leonelli de Moraesit et al it was observed that a higher frequency of partial ossification of the pterygospinous ligaments (19.36%) when compared to complete ossification (8.61%)3. Priman and Etter observed partial ossification in 8% of cases7, and Nayak et al who reported a percentage of 3.84%8. In another study by Bindu Aggarwal et al, the caroticoclinoid, interclinoid, petrosphenoid and pterygospinous ligaments were observed to be ossified in 51 sides of skulls out of 134 sides9. Das et al observed that the awareness of such anomalies of ossified ligaments is beneficial for maxillofacial and dental surgeons and anesthetists10. Tubbs et al earlier reported that anomalous bony obstructions could interfere with transcutaneous needle placement into the foramen ovale or distort anatomic relationships during approaches to the cranial base for mandibular nerve block11. In the present study, the insidence of pterygospinous bar was found to be 8%. This coincides with the results found by Priman and Etter.

 

CONCLUSION:

The knowledge about the incidence of pterygospinous bar helps to know the clinical manifestations of its presence. Since the bar forms a foramen, branches of the mandibular nerve may pass through it. Thus, this study may be important to anatomists, neurosurgeons, oral and maxillofacial surgeons, anesthetists in knowing about the ossification of pterigospinous ligament and its importance during surgery.

 

REFERENCE:

1.     P.L. Williams and R. Warwick, gray's anatomy, Churchill Livingstone, Edinburgh, UK, 36th edition, 1995.

2.     Julian J, Donald Y, Beard J, The accessory meningeal artery of man Journal of Anatomy 1961 Jul 95(3):366-402.

3.     Rafaela R. Rosa1, Horácio Faig-Leite2, Fabiola S. Faig-Leite3, Luiz C. Moraes1, Mari E.L. Moraes1, Edmundo M. Filho11Department of Diagnosis and Surgery, and 2Department of Biosciences and Diagnosis, Faculty of Dentistry, São Paulo State University, UNESP, São José dos Campos, SP, Brazil. 3Faculty of Medicine of Botucatu, UNESP, Botucatu, SP, Brazil, radiographic study of ossification of pterygospinous and pterygoalar ligaments by the hirtz axial technique Article in Acta odontológica latinoamericana: AOL January 2010.

4.     RS Tubbs, WR May Jr, N Apaydin, MM Shoja, G Shokouhi, M Loukas, et al. Ossification of ligaments near foramen ovale: An anatomical study with potential clinical significance regarding transcutaneous approaches to the skull base. Neurosurgery. 2009;65:60–64.

5.     M Piagkou, T Demesticha, G Piagkos, A Georgios, S Panagiotis. Lingual nerve entrapment in muscular and osseous structures. Int J Oral Sci. 2010;2:181–89. 

6.     Estudio Anatómico de los Puentes Óseos y Forámenes Pterigoespinosoy Pterigoalar en Cráneos Secosy su Relevancia Clínica Anatomical Study of the Pterygospinous and Pterygoalar Bony Bridges and Foramens in Dried Crania and its Clinical Relevance Suazo, G. I.; Zavando, M. D.; Smith, R. L. Anatomical study of the pterygospinous and pterygoalar bony bridges and foramens in dried crania and its clinical relevance. Int. J. Morphol., 28(2):405-408, 2010.

7.     Priman J, Etter LE. The pterygospinous and pterygoalar bars. Med Radiogr Photogr 1959;35:2-6.

8.     Nayak SR, Saralaya V, Prabhu LV, Pai MM, Vadgaonkar R, D’Costa S. Pterygospinous bar and foramina in Indian skulls: incidence and phylogenetic significance. Surg Radiol Anat. 2007;29:5-7.

9.     Bindu Aggarwal, Madhur Gupta, Harsh Kumar. Ossified Ligaments of the Skull. J . Anat. Soc. India 61(1) 37-40 (2012).

10.   Das S, Suri R, Kapur V. Ossification of caroticoclinoid ligament and    its clinical importance in skull- based surgery. Sao Paulo Med J 2007; 125(6) 351-3.

11.   Tubbs RS, May WR Jr, Apaydin N et al. Ossification of ligaments near the foramen ovale: an anatomic study with potential clinical significance regarding transcutaneous approaches to the skull. Neurosurgery 2009; 65(6) 60-4.

 

 

 

 

Received on 26.05.2016          Modified on 30.05.2016

Accepted on 14.06.2016        © RJPT All right reserved

Research J. Pharm. and Tech 2016; 9(8):1166-1168.

DOI: 10.5958/0974-360X.2016.00222.5