INTRODUCTION:

A study of the skull and its foramina provide insight into the evolutionary history of humankind. Of all the hominid fossils that scientists have discovered, the skull provides the richest information, since it has changed dramatically in size and shape during the course of evolution.(1)

The greater wing of sphenoid has many foramina which connect infra temporal fossa , orbit , temporal fossa with middle cranial fossa. Foramen rotundum , Foramen spinosum , Foramen ovale are the consistent Foramina in the sphenoid bone. Foramen Vesalius- a rare Foramen is also present in the greater wing of sphenoid. It transmits an emissary vein called Vein of Vesalius. Foramen Vesalius is a small, variable and an inconstant foramen located anteromedial to the foramen ovale and lateral to the foramen rotundum. This foramen is also known as emissary sphenoidal foramen. It opens below and lateral to scaphoid fossa1.

It transmits an emissary vein Vein of Vesalius, through which the cavernous venous sinus and pterygoid Venus plexus communicate. The importance of this foramen lies in the fact that it gives passage to an emissary vein. Emissary veins are those, which link the intracranial venous sinuses with veins outside the cranial cavity. They pass through the potential space between galea aponeurotica and pericranium. They are of importance in that they are channels along which infected thrombus can reach the interior of cranial cavity from outside it.(2)This could occur because the emissary vein passing through this foramen connects the venous system of the face, through the pterygoid venous plexus, to the cavernous sinus(7). FV is not seen in all the individuals but when present, it is very unlikely to misinterpret a normal well formed foramen as abnormal (Gupta et al.). Variations in the FV can be also explained by developmental reasons, because the sphenoid bone has a complex embryologic development, and the FV is one site of embryologic fusion in the spheoidbone(5,6). Another rare Foramen present is the Foramen innominatum. It is present between foramen ovale and foramen spinosum. Canaliculus innominatus transmits the lesser petrosal nerve.

Reason for Occurrence:

The small foramina represent the remnant of a vascular channel formed during osteogenesis (4). The reason for this is that, these sites are sites that have not ossified completely and therefore persist as foramina in the human skeleton.

MATERIALS AND METHODS:

30 dry South Indian skulls were used in this study and observed for accessory foramina. Probes were used to confirm their occurrence.photographs of the foramina were taken for proof and identification of side.

Table 1 number of foramen Vesalius and foramen Inominatum

Foramen	Present Percentage	Unilateral	Bilateral
Vesalius	20%	84%	16%
Inominatum	13%	75%	25%

Table 2 comparison of data on Foramen Vesalius

	Occurence	Unilateral	Bilateral
Present	20%	16.66%	3.33%
Pathmashri	12%	12%	0
Nehagupta	34%	20%	14%

Graph 1 : Comparison of Data on Foramen Vesalius

In the present study occurrence of Foramen inominatum was 13% of which75% is unilateral and 25% is bilateral. In the present study the occurrence of Foramen Vesalius was 20% out of 30 dry skulls, of which 84% was unilateral and 16% bilateral. (Table 2)

The above statement proves that Foramen exists predominantly on one side only (in both) owing to their inconsistent nature. The article by Pathmashri et al mentions the Occurrence of Foramen Vesalius in 12% of skulls and all are unilaterally present. In this study 50 human dry skulls were taken andexamined for the presence of foramenVesalius in both the

extra cranial view and intra cranial view. It is a very rareforamen and this Foramen was present only in 6 skulls out of 50.(8)Research done by Neha Gupta et al has34% occurrence of Vesalius. Unilateral Occurrence is 20% and bilateral occurrence is14%. The above information shows that there is a low rate of occurrence of inconsistent foramina however there can be increased rate of occurrence in specific populations of people. The below statement justifies this.

Foramen Vesalius is an inconsistent foramen of sphenoid bone. In our study, incidence of this foramen was 60% which is considerably higher than the previous studies. (8)

CONCLUSION:

In this study the occurrence of foramen Vesalius and foramen innominatum were 20% and 13% respectively.

The presence of accessory foramina is rare. Foramen inominatum has been given very low importance and has not been much researched on.

Owing to being a small and inconstant foramen, the FV is not routinely in attention during surgery. The knowledge of the occurrence of the FV may assist the neurosurgeon to realize that the FV is located very close to the FO, particularly at the extracranial view of the skull base. Therefore, in case it exists, the approach through the FO could be the more complicated procedure and the operation should be carefully performed to avoid the FV puncture.(3)

REFERENCES:

1. Namita A. Sharma, Rajendra S. Garud Morphometric evaluation and a report on the aberrations of the foramina in the intermediate region of the human cranial base: A study of an Indian population. Eur J Anat, 15 (3): 140-149 (2011)

2. Hussain Saheb Shaik, Muralidhar P Shepur , S.D Desai, S.T Thomas, G F Maavishettar, Haseena s. Study of foramen vesalius in South Indian skulls. Indian Journal of Medicine and Healthcare 2012.

3. Neha Gupta, Dr. Anjoo Yadav, R.J. Thomas, Ankit Shrivastava. Incidence of Foramen Vesalius in Adult Human North Indian Crania. Journal of Dental and Medical Sciences. May. 2014), PP 34-38

4. Aggarwal B, Gupta M, Goyal N. Accessory Foramina in the Body of Sphenoid Bone. Bombay Hospital Journal, Vol. 54, No. 2, 2012.

5. Gupta, N.; Ray, B. and Ghosh, S. Anatomic characteristics of fora- men vesalius. Kathmandu Univ. Med. J. (KUMJ), 3(2):155-8, 2005.

6. Shinohara, A. L.; de Souza Melo, C. G.; Silveira, E. M.; Lauris, J. R; Andreo, J. C. and de Castro Rodrigues, A. Incidence, morphology and morphometry of the foramen of Vesalius: complementary study for a safer planning and execution of the trigeminalrhizotomy technique. Surg. Radiol. Anat., 32(2):159-64, 2010.

7. J. Reymond, A. Charuta, and J. Wysocki, “The morphology and morphometry of the foramina of the greater wing of the human sphenoid bone,” FoliaMorphologica, vol. 64, no. 3, pp. 188–193, 2005.

8. Pathmashri. V.P, Dr. Thenmozhi. Occurrence, Shape and Size Of Foramen Vesalius in Dry Human Skulls. J. Pharm. Sci. And Res. Vol. 7(9), 2015, 718-719

Received on 01.07.2016 Modified on 08.07.2016

Research J. Pharm. and Tech 2016; 9(11): 1880-1882

DOI: 10.5958/0974-360X.2016.00385.1