INTRODUCTION:

Meningo-orbital foramen is an opening whose incidence is variable and not very definite. But it usually lies on or around the superior-lateral suture leading from superior orbital fissure (1). It is present either lateral to superior orbital fissure or confluent with the lateral end of the fissure or may be present in between these two extremes (2). It may be single or multiple, unilateral or bilateral. The other names for meningo-orbital foramen are lacrimal foramen, foramen of Hyrtl, foramen meningo-orbitale, cranio-orbital foramen, sinus canal foramen, sphenofrontal foramen (1). This foramen forms a passage for orbital branch (anastomising branch) of middle meningeal artery and lacrimal branch (anastomising branch) of ophthalmic artery (3). The orbital branch of middle meningeal artery provides the accessory blood supply to the orbit. Thus the communication between cranial cavity and orbit is produced by the abnormal origin of middle meningeal artery, lacrimal artery and ophthalmic artery (2).

The meningo-orbital foramen is of greater significance for ophthalmologists and neurosurgeons. They should have the knowledge about the significance of this foramen while reconstructing the anterior base of the skull, the orbit after orbital base surgery and during excision of meningiomas (3). This study was conducted to find out the percentage of occurance of meningo-orbital foramen in South Indian population.

MATERIALS AND METHODS:

55 adult dry human skulls of unknown sex of South Indian origin were investigated. Out of 55 dry skulls, 35 are full skull and 20 are base of the cut skull. The skulls which are damaged were excluded. They were obtained from Department of Anatomy, Saveetha Dental College, Chennai, Tamilnadu, India. The incidence of the meningo-orbital foramen was studied. Both orbits of each skull were observed carefully. The percentage of occurance of meningo-orbital foramen in right and left orbits were noted.

Observation:

The meningo-orbital foramen was studied in 55 dry human skulls. The presence of meningo-orbital foramen was observed in 30 skulls (54.54%). Among the total of 110 orbits, the meningo-orbital foramen was found in 40 orbits (36.36%) of the dry skull. The meningo-orbital foramen was observed to be unilateral in 17 skulls (56.66%). Unilateral meningo-orbital foramen was found to be in the right orbit in 4 skulls (23.52%) and left orbit in 13 skulls (76.47%). This foramen was present as bilateral in almost 10 skulls (33.33%). The meningo-orbital foramen was found to be single in 27 dry skulls (90%). The double foramina was observed to be in 3 skulls(10%). There was no presence of triple foramina or more than that in these dry skulls.

Total no. of skulls in which foramen is present	Presence of Single foramen-Unilaterally		Presence of Foramen-Bilaterally [Fig.3,4]
	Right Side [Fig.1]	Left Side [Fig.2]
30	4	13	10
(54.54%)	(23.52%)	(76.47%)	(33.33%)

Fig.1 SOF-Superior Orbital Fissure; MOF-Meningo Orbital Foramen(Right Side)

Fig.2 SOF-Superior Orbital Fissure MOF-Meningo-Orbital Foramen (Left Side)

Fig.3,4 Bilateral Meningo-orbital Foramen(MOF)

Fig.5 Double Meningo-orbital Foramen(MOF)

DISCUSSION:

The study examined the occurrence of meningo-orbital foramen in 110 orbits of 55 dry skulls. On comparing the present study with the study conducted by other authors, there is a wide range of variation. The older research suggested that this foramen is a rare occurrence while the recent study indicate a frequent incidence of this foramen. This variation may be due to genetic, nutritional, climatic zone and the surgeons should have this knowledge before performing surgery in orbital cavity(4). The highest percentage of incidence of the meningo-orbital foramen was found to be 80.4% in the study done by Ashwin Krishnamurthy et al. in 138 skulls of South Indian population(5).The lowest percentage of occurrence of this foramen was found to be 6% in the study done by Santo et al. in 50 skulls of Brazalian population(6).This meningo-orbital foramen represent an embryonic conduit between the supraorbital division of the stapedial artery and the permanent stem of ophthalmic artery. But in adults this foramen appears to be a connecting vessel between the orbital branch of anterior division of middle meningeal artery and the lacrimal branch of ophthalmic artery. Hence this foramen was called as ‘Stapediolophthalmolacrimal foramen’ by many authors(7).In the study done by Jan Kwiatkowski, the incidence of the meningo-orbital foramen was seen to be higher in females compared to males. Also in his study the multiple foramina were observed only in female skulls(8).Thus both the occurrence and morphology of the meningo-orbital foramen presented a significant sex differences in humans. Thus this knowledge can be used in forensic science.

CONCLUSION:

The present study reveals valuable insights on the incidence of Meningo-orbital foramen in South Indian skulls. It was found to be present in 30 skulls(54.54%) out of 55 skulls. This knowledge will be clinically significant for ophthalmologists, neurosurgeons and radiologists for performing safe surgeries and avoiding vascular catastrophe. Also, as the meningo-orbital foramen is a vascular link between orbit and cranium, it is clinically significant.

REFERENCES:

1 Arvind Kumar Pankaj, Navneet Kumar, Rakesh Kumar Verma. "Incidence of Meningo-Orbital Foramen in Dry Skull and Its Clinical Relevance.” Indian Journal of Basic and Applied Medical Research; March 2013:Issue-6, Vol.-2,P.514-517.

2. Ashwin Krishnamurthy, Soubhagya R Nayak, Latha V Prabhu, Dil Islam Mansur, Lakshmi Ramanathan, Sampath Madhyastha, Vasudha Saralaya. ”The morphology of meningo-orbital foramen in south Indian population.”Bratisl Lek Listy 2008;109 (11).P.517-519.

3. Daizy Singh, Gursharan Singh Dhindsa, Sandeep Singh and Jaswinder Kaur. ”Morphology and Topographic anatomy of Meningo-orbital foramen in North-Indian Population. ”International Journal of Advances in Health Sciences (IJHS).Vol2, Issue2, 2015, pp241-245.

4. Tomaszewska, Agnieszka, zelazniewicz. Morphology and Morphometry of the Meningo-orbital foramen as a result of Plastic responses to the ambient temperature and its lineal relevance. Journal of Craniofacial surgery May 2014-Vol25-Issue3-p-1033-1037

5 Ashwin Krishnamurthy, Nayak SR, Prabhu LV, Mansur DI, Ramanathan L, Madhyastha S, Saralaya V. The morphology of meningo-orbital foramen in South Indian population. Bratisl Lek Listy.2008;109 (11):517-519

6. Santo Neto, H., Penteado C.V. and De Carvalho, V.C.(1984).Presence of a groove in the lateral wall of the human orbit.J Anatomy-138,631-633.

7. Georgiou C, Cassell. The Foramen Meningo-orbitale and its Relationship to the Development of the Ophthalmic Artery. J Anatomy.1992;180(1):119-125.

8. Jan Kwiatkowski, Jarostaw Wysocki, Stanistaw Nitek. The morphology and morphometry of the so-called “meningo-orbital foramen” in humans. Folia Morphol.Vol.62,No.4,pp.323-325.29July 2003.

Received on 30.04.2016 Modified on 22.05.2016

Research J. Pharm. and Tech. 2016; 9(7):880-882.

DOI: 10.5958/0974-360X.2016.00167.0