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Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population Analyse morphométrique et anatomique des variations du foramen infra-orbitaire : une étude sur la population adulte de l’Inde du Nord S.G. Dixit a,∗, J. Kaur b, A.K. Nayyar a, D. Agrawal a a b
Department of Anatomy, All India Institute of Medical Sciences (AIIMS), Jodhpur, Rajasthan 342005, India Department of Anatomy, ESI Dental College, New Delhi, India
KEYWORDS Infraorbital foramen; Morphometry; Accessory; Procedural risks
∗
Summary Purpose. — Various studies have been conducted on morphometric variations of infraorbital foramen to provide data to surgeons for nerve block in infraorbital region. This study aims to analyse the anatomical variations by comparing various morphometric measurements of infraorbital foramen in dry skulls of adult North Indian population. This study becomes relevant in the present study group as very scant data is available about the variations and morphometric measurements in Indian population. The data thus collected can be standardized and become useful for the surgeons working in this area of face. Materials and methods. — The study was conducted on 75 dry adult human skulls, which were a part of Department of Anatomy, used for teaching purposes in medical colleges. Straight distance of the Infraorbital foramen from the infraorbital rim, supraorbital foramen and sagittal plane was measured. The position of the infraorbital foramen was determined in relation to maxillary teeth and supraorbital foramen. The data thus obtained was analysed. Results. — The distance of infraorbital foramen from infraorbital rim, supraorbital foramen, sagittal plane in the present study was found to be 6.71 ± 1.11 mm, 42.02 ± 4.31 mm and 31.94 ± 4.88 mm respectively. The position of infraorbital foramen was lateral in relation to supraorbital foramen (in 88% of cases). Infraorbital foramen was above the 1st premolar tooth in most of the cases. Accessory infraorbital foramen was found in 11.2% cases (double foramen). Conclusion. — The data thus obtained will perhaps be helpful to the surgeons in identifying the extent of the operative field thereby reducing procedural risks. © 2014 Elsevier Masson SAS. All rights reserved.
Corresponding author. E-mail address: [email protected] (S.G. Dixit).
1286-0115/$ – see front matter © 2014 Elsevier Masson SAS. All rights reserved. http://dx.doi.org/10.1016/j.morpho.2014.02.008
Please cite this article in press as: Dixit SG, et al. Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population. Morphologie (2014), http://dx.doi.org/10.1016/j.morpho.2014.02.008
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S.G. Dixit et al.
MOTS CLÉS Foramen infra-orbitaire ; Morphométrie ; Risques de procédure
Résumé Objectif. — Des études variées ont été menées sur les variations morphométriques du foramen infra-orbitaire afin de fournir des données aux chirurgiens pour réaliser des blocs nerveux dans la région infra-orbitaire. Cette étude a pour objectif d’analyser les variations anatomiques en comparant les diverses mesures morphométriques du foramen infra-orbitaire dans des crânes secs d’Indiens du Nord adulte. Cette étude est pertinente dans le groupe d’étude présent car très peu de données sont disponibles sur les variations et les mesures morphométriques pour la population indienne. Les données ainsi collectées peuvent être standardisées et devenir utiles pour les chirurgiens travaillant sur cette partie du visage. Matériels et méthodes. — L’étude a été menée sur 75 crânes secs humains adultes appartenant au département d’anatomie, utilisés pour l’enseignement dans les collèges médicaux. La distance en droite ligne entre le foramen infra-orbitaire et la bordure infra-orbitaire, le foramen supra-orbitaire et le plan sagittal a été mesurée. La position du foramen infra-orbitaire a été déterminée en relation avec les dents maxillaires et le foramen supra-orbitaire. Les données que nous avons obtenues ont été analysées. Résultats. — La distance entre le foramen infra-orbitaire de la bordure infra-orbitaire, du foramen supra-orbitaire, et du plan sagittal dans le cas d’étude présent a été trouvée à 6,71 ± 1,11 mm, 42,02 ± 4,31 mm et 31,94 ± 4,88 mm respectivement. La position du foramen infra-orbitaire était latérale par rapport au foramen supra-orbitaire (dans 88 % des cas). Le foramen infra-orbitaire était au-dessus de la première dent prémolaire dans la plupart des cas. Accessoirement, le foramen infra-orbitaire a été trouvé dans 11,2 % des cas (double foramen). Conclusion. — Les données ainsi obtenues pourront peut-être servir d’aide pour les chirurgiens en identifiant l’étendue du champ opératoire, réduisant ainsi les risques de procédure. © 2014 Elsevier Masson SAS. Tous droits réservés.
Introduction The infraorbital foramen (IOF) is bilaterally located in the maxillary bone on its frontal aspect, approximately 0.5—1 cm below the infraorbital margin through which infraorbital nerves and vessels pass. Infraorbital nerve is considered as a continuation of maxillary nerve, which is the second division of trigeminal nerve (fifth cranial nerve). Trigeminal nerve divides into 3 branches namely ophthalmic, maxillary and mandibular. Three areas of face can be delineated to indicate the peripheral nerve. Each division of the trigeminal nerve is embryologically associated with each developing facial process which gives rise to a specific area of the adult face. The ophthalmic nerve is related to frontonasal process, the maxillary nerve with the maxillary process and the mandibular nerve with the mandibular process. The maxillary division of trigeminal nerve is entirely sensory which supplies skin of the lower eyelid, prominence of the cheek, the alar part of nose, part of temple and the upper lip. It leaves the skull via foramen rotundum which opens directly into the posterior wall of pterygopalatine fossa. It gives ganglionic branches to the pterygopalatine ganglion and then continues on the upper part of posterior surface of maxilla into the inferior orbital fissure as infraorbital nerve. Maxillary nerve gives some direct branches from the trunk that is meningeal, ganglionic, zygomatic, posterior, middle and anterior superior alveolar and continues as infraorbital nerve. It also gives branches through pterygopalatine ganglion namely orbital, nasopalatine, posterior superior nasal, palatine and pharyngeal. The infraorbital nerve passes through the infraorbital groove, then canal and emerges on the face through
infraorbital foramen where it gives of palpebral, nasal and superior labial branches. Various studies have reported other foramina close to infraorbital foramen which were termed as accessory infraorbital foramen. Few studies found up to four of such accessory infraorbital foramina which were more common in Mexican population [1—5]. The region of infraorbital foramen assumes importance during surgeries or in fractures, mostly orbital fractures which involve the floor particularly the region of infraorbital groove. The classic blow out fracture leaves the orbital rim intact and generally entraps soft tissue structures out of which infraorbital nerve involvement leads to ipsilateral sensory disturbance of the skin of maxillary region of face [6]. A nerve block is essentially needed for effective blockage of infraorbital nerve during local anesthesia procedures and various surgeries, like plastic surgeries, rhinoplasty, etc., performed around infraorbital foramen [7,8]. One such surgery is Caldwell-Luc surgery which is a type of maxillotomy whose passage has external access to maxillary sinus [9]. The precise location of the foramen is determined from morphometric variations from reference points and helps to locate the infraorbital plexus region which facilitates protection against procedural neurovascular injuries. The position of infraorbital foramen also determines the orientation of an acupuncture point which can be useful in treatment of trigeminal neuralgia [10]. This study aims to analyse the anatomical variations by comparing various morphometric measurements of infraorbital foramen in dry skulls of adult North Indian population. The data thus collected can be standardized and become useful for the surgeons working in this area of face.
Please cite this article in press as: Dixit SG, et al. Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population. Morphologie (2014), http://dx.doi.org/10.1016/j.morpho.2014.02.008
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Morphometric analysis and anatomical variations of infraorbital foramen
Figure 1 Showing measurements. A. Distance of infraorbital foramen from infraorbital rim. B. Distance of infraorbital foramen from supraorbital margin. C. Distance of infraorbital foramen from sagittal plane. Affichage des mesures. A. Distance entre le foramen infraorbitaire et la bordure infra-orbitaire. B. Distance entre le foramen infra-orbitaire et la marge supra-orbitaire. C. Distance entre le foramen infra-orbitaire et le plan sagittal.
Materials and methods The aim of the study was to elucidate the morphological features and precise anatomical position of infraorbital foramen with reference to surrounding anatomical landmarks in North Indian population. The study was conducted on 75 dry adult human skulls which were a part of Department of Anatomy used for teaching purposes in medical colleges. Skulls with bony deformities and fractures were excluded from the study. Straight distance of the infraorbital foramen from the infraorbital rim, supraorbital foramen and sagittal plane was measured (Fig. 1). The position of the infraorbital foramen was determined in relation to maxillary teeth and supraorbital foramen. Measurements were carried out by two researchers separately. Thereafter the data was pooled, median, mean and standard deviation were obtained. All measurements were made on right and left sides. Data obtained was statistically analysed using SPSS software. Presence of accessory orbital foramen was determined in each skull (Fig. 2).
Figure 2
3
Showing accessory infraorbital foramen.
Affichage accessoire du foramen infra-orbitaire. Table 2 Position of infraorbital foramen (IOF) in relation to supraorbital foramen (SOF). Position du foramen infra-orbitaire par rapport au foramen supra-orbitaire. Position of IOF
% in left side
Lateral to SOF Medial SOF In line with SOF
88% 22% 0%
% in right side 88% 10% 11%
Results The mean and standard deviation derived from morphometric measurements on 75 adult human skulls is shown in Table 1. The difference of values between right and left sides were statistically non-significant (Table 1). Since there was no side dimorphism, therefore the data was pooled and combined mean and standard deviation were calculated (Table 1). The position of infraorbital foramen was lateral in relation to supraorbital foramen (in 88% of cases) as shown in Table 2. Position of infraorbital foramen in relation to maxillary premolars and molars is represented in Table 3. Infraorbital foramen was above the 1st premolar tooth in most of the cases.
Table 1 Morphometric measurements in mm (mean ± standard deviation [S.D.]) of the distance of infraorbital foramen (IOF) from various points. Mesures morphométriques en mm (moyenne ± écart-type [S.D.]) de la distance du foramen infra-orbitaire (FII) provenant de divers points. Distance of IOF from
Infraorbital rim Supraorbital foramen Sagittal plane
Mean ± S.D. Right
Left
Total
P-value
7.18 ± 1.50 41.68 ± 3.48 31.94 ± 4.88
6.25 ± 0 42.37 ± 5.43 31.94 ± 4.88
6.71 ± 1.11 42.02 ± 4.31 31.94 ± 4.88
.065 .0751 1.00
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S.G. Dixit et al. Table 3 Position of the infraorbital foramen (IOF) in relation to premolars and molars. Position du foramen infra-orbitaire par rapport aux prémolaires et molaires. Position of IOF
% in left side
% in right side
Above the 1st premolar tooth Above the 2nd premolar tooth Between premolar and molar teeth Between 1st and 2nd molar teeth
44% 33% 22% 11%
55% 33% 22% 0%
Table 4 is showing comparison of the results of present study with that of other researchers. Accessory infraorbital foramen was found in 11.2% cases (double foramen).
Discussion The present study was undertaken to collect data about the precise anatomical position of infraorbital foramen in relation to various surrounding landmarks in dry skulls of North Indian population. The presence of accessory infraorbital foramen was also determined. The distance of infraorbital foramen from infraorbital rim in the present study was found to be 6.71 ± 1.11 mm (Table 1), similar to the results of Karakas et al. (6.7 ± 1.11 mm) in Caucasian adult male skulls, Lopes et al. (6.5 ± 1.7 mm on right side, 6.76 ± 1.64 mm on left side) and Macedo et al. (6.37 mm) in Brazilian skulls, Hindy and Abdel-Raouf (6.10 mm) in adult Egyptians, and Singh (6.16 ± 1.8 mm) in Indian skulls (Table 4) [5,11—14]. The present study results were lower than that of Chung et al. (8.60 mm) in Korean skulls, Canan et al. (8.30 mm in females, 10.9 mm in males), Kazkayasi et al. (7.19 mm), Agthong et al. (7.8 to 8.0 mm) in Asian adults, Apinhasmit et al. (9.23 ± 2.03 mm) in Thai adult skulls [1,2,15—17]. The present study showed no statistically significant differences in the distance between infraorbital foramen and infraorbital margin on right and left sides unlike few authors. The distance of infraorbital foramen from supraorbital foramen was found to be 42.02 ± 4.31 mm in our study (Table 1) while Chung et al. measured this distance to be 45.6 mm in Korean skulls [16].
Table 4 Comparison of mean distance between infraorbital foramen and infraorbital rim with other studies. Comparaison de la distance moyenne entre le foramen infraorbitaire et la bordure infra-orbitaire avec d’autres études. Study
Mean distance (mm)
Kazkayasi et al. Hindy and Abdel-Raouf Chung et al. Esper et al. Karakas et al. Macedo et al. Present study
7.19 ± 1.39 6.1 ± 2.4 8.60 6.80 6.7 6.37 6.71 ± 1.11
The infraorbital foramen was 31.94 ± 4.88 mm from the midsagittal plane (Table 1) which is much higher than the results of the study of Chung et al. in Korean skulls (27.2 mm) [16]. Aziz et al. reported this distance to be 27.9 mm (right), 27.5 mm (left) in men and 25.5 mm (right), 26.9 (left) in women [18]. The position of infraorbital foramen was lateral to supraorbital foramen in most cases (88%) in the present study (Table 2) which was much higher than the findings of Chung et al. (63.6%) and that of Aziz et al. (40% in men, 33% in women) [16,18]. The infraorbital foramen was more commonly situated above the 1st premolar tooth (44% in left side, 55% in right side) in the present study which was comparable with the study of Aziz et al. (64%) [18]. The knowledge of these morphometric variations of infraorbital foramen is significant for local anesthetic procedures and blockage of infraorbital nerve [8,19]. The approximate position of the infraorbital foramen helps us to determine the location of the infraorbital plexus which as mentioned by Hwang and Biak is a risk zone while performing plastic surgery [7]. This information about the interindividual anatomic variability of the infraorbital region helps in reducing the risks of procedural neurovascular (iatrogenic) injuries due to presence of additional branch of infraorbital nerve in surgeries such as those of anterior and superior walls of maxilla (maxillofacial surgery), rhinoplasty, surgeries of orbital floor, type I Le Fort osteotomies and various procedures involving intra- and extra-oral anesthesia [8,12,20,21]. The knowledge about variations in the position of IOF also becomes significant for techniques involving regional block anesthesia and for acupuncture used for treatment of trigeminal neuralgia [10,16,22]. The 2nd division of trigeminal nerve is an important potential pathway for perineural spread of malignancy. Imaging is a primary method for its detection. Normal appearance of infraorbital foramen shows fat pads and obliteration of this fat pad indicates spread of tumor in this canal. Therefore while doing tomographic studies for planning surgical resection or identifying target region for radiation therapy, infraorbital foramen can be identified by detection of these fat pads [23]. Accessory foramen was found in 11.2% cases (double foramen) in our study. It was comparable with study by Singh (10% more than 1 foramen) in Indian skulls, Canan et al. (11.5% single accessory foramen) and Elias et al. (10% in Brazilian skulls) [3,5,15]. The incidence of accessory foramen observed was lower in studies of Agthong et al. (3.6% in right, 4.5% left), Apinhasmit et al. (3.3% in Thai skulls), Kazkayasi et al. (5.7%) [1,2,4]. The knowledge of presence of accessory foramens is also essential during anesthesia, as the amount used may be inappropriate due to additional branch of infraorbital nerve in these foramens. Previous studies have also analysed the anatomical variations using different reference points in different population groups. Our study becomes relevant in the present study group as very scant data is available about the variations and morphometric measurements in Indian population. The data thus obtained will perhaps be helpful to the surgeons in identifying the extent of the operative field thereby reducing procedural risks.
Please cite this article in press as: Dixit SG, et al. Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population. Morphologie (2014), http://dx.doi.org/10.1016/j.morpho.2014.02.008
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Morphometric analysis and anatomical variations of infraorbital foramen
Conclusion The results when compared with previous studies show a large amount of variation in the anatomical position of IOF in relation to different reference points which is due to a diversity of investigated populations. As the data is dependent on population groups, therefore the present study becomes relevant as scant data is available in Indian population. These results can play a role in preventing the iatrogenic injuries during procedures involving the infraorbital region.
[10]
[11]
[12]
[13]
Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
[14] [15]
References [1] Agthong S, Huanmanop T, Chentanez V. Anatomical variations of the supraorbital, infraorbital, and mental foramina related to gender and side. J Oral Maxillofac Surg 2005;63(6):800—4. [2] Apinhasmit W, Chompoopong S, Methathrathip D, et al. Supraorbital notch/foramen, infraorbital foramen and mental foramen in Thais: anthropometric measurements and surgical relevance. J Med Assoc Thai 2006;89(5):675—82. [3] Elias MG, Silva RB, Pimentel ML, et al. Morphometric analysis of the infraorbital foramen and accessories foraminas in Brazilian skulls. Int J Morphol 2004;22(4):273—8. [4] Kazkayasi M, Ergin A, Ersoy M, et al. Microscopic anatomy of infraorbital canal, nerve and foramen. Otolaryngol Head Neck Surg 2003;129(6):692—7. [5] Singh R. Morphometric analysis of infraorbital foramen in Indian dry skulls. Anat Cell Biol 2011;44:79—83. [6] Standring S, et al. Gray’s anatomy: anatomical basis of clinical practice. 40th ed Edinburgh: Churchill Livingstone; 2008. p. 656. [7] Hwang K, Biak SH. Surgical anatomy of Korean adults. J Craniofac Surg 1999;10(2):129—34. [8] Zide B, Swift R. How to block and tackle the face. Plast Reconstr Surg 1998;101(3):840—51. [9] Brandão FB, Machado MRC, Aquino JEP, et al. The foramen and infraorbital nerve relating to the surgery for external access to
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the maxillary sinus (Caldwell-Luc). Int Arch Otorhinolaryngol (Sao Paulo) 2008;12(3):342—6. Esper RS, Yara J, Yamamura Y, et al. Relac ¸Ões anatômicas do ponto de acupuntura E-2 (Sibai) localizado no forame infraorbital. Rev Paul Acupunt 1998;4:19—21. Hindy AM, Abdel-Raouf F. A study of infraorbital foramen, canal and nerve in adult Egyptians. Egypt Dent J 1993;39(4): 573—80. Karakas P, Bozkur MG, Oguz O. Morphometric measurements from various reference points in the orbit of male Caucasians. Surg Radiol Anat 2003;24:358—62. Lopes PTC, Pereira GAM, Santos AMPV, et al. Morphometric analysis of the infraorbital foramen related to gender and laterality in dry skulls of adult individuals in southern Brazil. Braz J Morphol Sci 2009;26(1):19—22. Macedo VC, Cabrini RR, Faig-Leite H. Infraorbital foramen location in dry human skulls. Braz J Morphol Sci 2009;26:35—8. Canan S, Asim OM, Okan B, et al. Anatomic variations of the infraorbital foramen. Ann Plast Surg 1999;43(6):613—7. Chung MS, Kim HJ, Kang HS, et al. Locational relationship of the supraorbital notch or foramen and infraorbital and mental foramina in Koreans. Acta Anat 1995;154:162—6. Kazkayasi M, Ergin A, Ersoy M, et al. Certain anatomical relations and the precise morphometry of the infraorbital foramen — canal and groove: an anatomical and cephalometric study. Laryngoscope 2001;111(4 Pt 1):609—14. Aziz SR, Marchema JM, Puran A. Anatomic characteristics of the infraorbital foramen: a cadaver study. J Oral Maxillofac Surg 2000;58:992—6. Salomão JIS, Salomão JAS, Salomão Costa RCS. New anatomic intraoral reference for the anesthetic blocking of the anterior and middle maxillary alveolar nerves (infraorbital block). Braz Dent J 1990;1(1):31—6. Lawrence JE, Poole MD. Mid-facial sensation following craniofacial surgery. Br J Plast Surg 1992;45(7):519—22. Mozsary PG, Middleton RA. Microsurgical reconstruction of the infraorbital nerves. J Oral Surg 1983;41(11):697—700. Radwan IA, Saito S, Goto F. High-concentration tetracaine for the management of trigeminal neuralgia: quantitative assessment of sensory function after peripheral nerve block. Clin J Pain 2001;17:323—6. Yamamoto M, Curtin HD, Suwansaard P, Sakai O, Sano T, Okano T. Identification of juxtaforaminal Fat pads of the second division of the trigeminal pathway on MRI and CT. Am J Roentgenol 2004;182(2):385—92.
Please cite this article in press as: Dixit SG, et al. Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population. Morphologie (2014), http://dx.doi.org/10.1016/j.morpho.2014.02.008
ARTICLE IN PRESS
MORPHO-214; No. of Pages 5 Morphologie (2014) xxx, xxx—xxx
Disponible en ligne sur
ScienceDirect www.sciencedirect.com
ORIGINAL ARTICLE
Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population Analyse morphométrique et anatomique des variations du foramen infra-orbitaire : une étude sur la population adulte de l’Inde du Nord S.G. Dixit a,∗, J. Kaur b, A.K. Nayyar a, D. Agrawal a a b
Department of Anatomy, All India Institute of Medical Sciences (AIIMS), Jodhpur, Rajasthan 342005, India Department of Anatomy, ESI Dental College, New Delhi, India
KEYWORDS Infraorbital foramen; Morphometry; Accessory; Procedural risks
∗
Summary Purpose. — Various studies have been conducted on morphometric variations of infraorbital foramen to provide data to surgeons for nerve block in infraorbital region. This study aims to analyse the anatomical variations by comparing various morphometric measurements of infraorbital foramen in dry skulls of adult North Indian population. This study becomes relevant in the present study group as very scant data is available about the variations and morphometric measurements in Indian population. The data thus collected can be standardized and become useful for the surgeons working in this area of face. Materials and methods. — The study was conducted on 75 dry adult human skulls, which were a part of Department of Anatomy, used for teaching purposes in medical colleges. Straight distance of the Infraorbital foramen from the infraorbital rim, supraorbital foramen and sagittal plane was measured. The position of the infraorbital foramen was determined in relation to maxillary teeth and supraorbital foramen. The data thus obtained was analysed. Results. — The distance of infraorbital foramen from infraorbital rim, supraorbital foramen, sagittal plane in the present study was found to be 6.71 ± 1.11 mm, 42.02 ± 4.31 mm and 31.94 ± 4.88 mm respectively. The position of infraorbital foramen was lateral in relation to supraorbital foramen (in 88% of cases). Infraorbital foramen was above the 1st premolar tooth in most of the cases. Accessory infraorbital foramen was found in 11.2% cases (double foramen). Conclusion. — The data thus obtained will perhaps be helpful to the surgeons in identifying the extent of the operative field thereby reducing procedural risks. © 2014 Elsevier Masson SAS. All rights reserved.
Corresponding author. E-mail address: [email protected] (S.G. Dixit).
1286-0115/$ – see front matter © 2014 Elsevier Masson SAS. All rights reserved. http://dx.doi.org/10.1016/j.morpho.2014.02.008
Please cite this article in press as: Dixit SG, et al. Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population. Morphologie (2014), http://dx.doi.org/10.1016/j.morpho.2014.02.008
+Model MORPHO-214; No. of Pages 5
ARTICLE IN PRESS
2
S.G. Dixit et al.
MOTS CLÉS Foramen infra-orbitaire ; Morphométrie ; Risques de procédure
Résumé Objectif. — Des études variées ont été menées sur les variations morphométriques du foramen infra-orbitaire afin de fournir des données aux chirurgiens pour réaliser des blocs nerveux dans la région infra-orbitaire. Cette étude a pour objectif d’analyser les variations anatomiques en comparant les diverses mesures morphométriques du foramen infra-orbitaire dans des crânes secs d’Indiens du Nord adulte. Cette étude est pertinente dans le groupe d’étude présent car très peu de données sont disponibles sur les variations et les mesures morphométriques pour la population indienne. Les données ainsi collectées peuvent être standardisées et devenir utiles pour les chirurgiens travaillant sur cette partie du visage. Matériels et méthodes. — L’étude a été menée sur 75 crânes secs humains adultes appartenant au département d’anatomie, utilisés pour l’enseignement dans les collèges médicaux. La distance en droite ligne entre le foramen infra-orbitaire et la bordure infra-orbitaire, le foramen supra-orbitaire et le plan sagittal a été mesurée. La position du foramen infra-orbitaire a été déterminée en relation avec les dents maxillaires et le foramen supra-orbitaire. Les données que nous avons obtenues ont été analysées. Résultats. — La distance entre le foramen infra-orbitaire de la bordure infra-orbitaire, du foramen supra-orbitaire, et du plan sagittal dans le cas d’étude présent a été trouvée à 6,71 ± 1,11 mm, 42,02 ± 4,31 mm et 31,94 ± 4,88 mm respectivement. La position du foramen infra-orbitaire était latérale par rapport au foramen supra-orbitaire (dans 88 % des cas). Le foramen infra-orbitaire était au-dessus de la première dent prémolaire dans la plupart des cas. Accessoirement, le foramen infra-orbitaire a été trouvé dans 11,2 % des cas (double foramen). Conclusion. — Les données ainsi obtenues pourront peut-être servir d’aide pour les chirurgiens en identifiant l’étendue du champ opératoire, réduisant ainsi les risques de procédure. © 2014 Elsevier Masson SAS. Tous droits réservés.
Introduction The infraorbital foramen (IOF) is bilaterally located in the maxillary bone on its frontal aspect, approximately 0.5—1 cm below the infraorbital margin through which infraorbital nerves and vessels pass. Infraorbital nerve is considered as a continuation of maxillary nerve, which is the second division of trigeminal nerve (fifth cranial nerve). Trigeminal nerve divides into 3 branches namely ophthalmic, maxillary and mandibular. Three areas of face can be delineated to indicate the peripheral nerve. Each division of the trigeminal nerve is embryologically associated with each developing facial process which gives rise to a specific area of the adult face. The ophthalmic nerve is related to frontonasal process, the maxillary nerve with the maxillary process and the mandibular nerve with the mandibular process. The maxillary division of trigeminal nerve is entirely sensory which supplies skin of the lower eyelid, prominence of the cheek, the alar part of nose, part of temple and the upper lip. It leaves the skull via foramen rotundum which opens directly into the posterior wall of pterygopalatine fossa. It gives ganglionic branches to the pterygopalatine ganglion and then continues on the upper part of posterior surface of maxilla into the inferior orbital fissure as infraorbital nerve. Maxillary nerve gives some direct branches from the trunk that is meningeal, ganglionic, zygomatic, posterior, middle and anterior superior alveolar and continues as infraorbital nerve. It also gives branches through pterygopalatine ganglion namely orbital, nasopalatine, posterior superior nasal, palatine and pharyngeal. The infraorbital nerve passes through the infraorbital groove, then canal and emerges on the face through
infraorbital foramen where it gives of palpebral, nasal and superior labial branches. Various studies have reported other foramina close to infraorbital foramen which were termed as accessory infraorbital foramen. Few studies found up to four of such accessory infraorbital foramina which were more common in Mexican population [1—5]. The region of infraorbital foramen assumes importance during surgeries or in fractures, mostly orbital fractures which involve the floor particularly the region of infraorbital groove. The classic blow out fracture leaves the orbital rim intact and generally entraps soft tissue structures out of which infraorbital nerve involvement leads to ipsilateral sensory disturbance of the skin of maxillary region of face [6]. A nerve block is essentially needed for effective blockage of infraorbital nerve during local anesthesia procedures and various surgeries, like plastic surgeries, rhinoplasty, etc., performed around infraorbital foramen [7,8]. One such surgery is Caldwell-Luc surgery which is a type of maxillotomy whose passage has external access to maxillary sinus [9]. The precise location of the foramen is determined from morphometric variations from reference points and helps to locate the infraorbital plexus region which facilitates protection against procedural neurovascular injuries. The position of infraorbital foramen also determines the orientation of an acupuncture point which can be useful in treatment of trigeminal neuralgia [10]. This study aims to analyse the anatomical variations by comparing various morphometric measurements of infraorbital foramen in dry skulls of adult North Indian population. The data thus collected can be standardized and become useful for the surgeons working in this area of face.
Please cite this article in press as: Dixit SG, et al. Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population. Morphologie (2014), http://dx.doi.org/10.1016/j.morpho.2014.02.008
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Morphometric analysis and anatomical variations of infraorbital foramen
Figure 1 Showing measurements. A. Distance of infraorbital foramen from infraorbital rim. B. Distance of infraorbital foramen from supraorbital margin. C. Distance of infraorbital foramen from sagittal plane. Affichage des mesures. A. Distance entre le foramen infraorbitaire et la bordure infra-orbitaire. B. Distance entre le foramen infra-orbitaire et la marge supra-orbitaire. C. Distance entre le foramen infra-orbitaire et le plan sagittal.
Materials and methods The aim of the study was to elucidate the morphological features and precise anatomical position of infraorbital foramen with reference to surrounding anatomical landmarks in North Indian population. The study was conducted on 75 dry adult human skulls which were a part of Department of Anatomy used for teaching purposes in medical colleges. Skulls with bony deformities and fractures were excluded from the study. Straight distance of the infraorbital foramen from the infraorbital rim, supraorbital foramen and sagittal plane was measured (Fig. 1). The position of the infraorbital foramen was determined in relation to maxillary teeth and supraorbital foramen. Measurements were carried out by two researchers separately. Thereafter the data was pooled, median, mean and standard deviation were obtained. All measurements were made on right and left sides. Data obtained was statistically analysed using SPSS software. Presence of accessory orbital foramen was determined in each skull (Fig. 2).
Figure 2
3
Showing accessory infraorbital foramen.
Affichage accessoire du foramen infra-orbitaire. Table 2 Position of infraorbital foramen (IOF) in relation to supraorbital foramen (SOF). Position du foramen infra-orbitaire par rapport au foramen supra-orbitaire. Position of IOF
% in left side
Lateral to SOF Medial SOF In line with SOF
88% 22% 0%
% in right side 88% 10% 11%
Results The mean and standard deviation derived from morphometric measurements on 75 adult human skulls is shown in Table 1. The difference of values between right and left sides were statistically non-significant (Table 1). Since there was no side dimorphism, therefore the data was pooled and combined mean and standard deviation were calculated (Table 1). The position of infraorbital foramen was lateral in relation to supraorbital foramen (in 88% of cases) as shown in Table 2. Position of infraorbital foramen in relation to maxillary premolars and molars is represented in Table 3. Infraorbital foramen was above the 1st premolar tooth in most of the cases.
Table 1 Morphometric measurements in mm (mean ± standard deviation [S.D.]) of the distance of infraorbital foramen (IOF) from various points. Mesures morphométriques en mm (moyenne ± écart-type [S.D.]) de la distance du foramen infra-orbitaire (FII) provenant de divers points. Distance of IOF from
Infraorbital rim Supraorbital foramen Sagittal plane
Mean ± S.D. Right
Left
Total
P-value
7.18 ± 1.50 41.68 ± 3.48 31.94 ± 4.88
6.25 ± 0 42.37 ± 5.43 31.94 ± 4.88
6.71 ± 1.11 42.02 ± 4.31 31.94 ± 4.88
.065 .0751 1.00
Please cite this article in press as: Dixit SG, et al. Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population. Morphologie (2014), http://dx.doi.org/10.1016/j.morpho.2014.02.008
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S.G. Dixit et al. Table 3 Position of the infraorbital foramen (IOF) in relation to premolars and molars. Position du foramen infra-orbitaire par rapport aux prémolaires et molaires. Position of IOF
% in left side
% in right side
Above the 1st premolar tooth Above the 2nd premolar tooth Between premolar and molar teeth Between 1st and 2nd molar teeth
44% 33% 22% 11%
55% 33% 22% 0%
Table 4 is showing comparison of the results of present study with that of other researchers. Accessory infraorbital foramen was found in 11.2% cases (double foramen).
Discussion The present study was undertaken to collect data about the precise anatomical position of infraorbital foramen in relation to various surrounding landmarks in dry skulls of North Indian population. The presence of accessory infraorbital foramen was also determined. The distance of infraorbital foramen from infraorbital rim in the present study was found to be 6.71 ± 1.11 mm (Table 1), similar to the results of Karakas et al. (6.7 ± 1.11 mm) in Caucasian adult male skulls, Lopes et al. (6.5 ± 1.7 mm on right side, 6.76 ± 1.64 mm on left side) and Macedo et al. (6.37 mm) in Brazilian skulls, Hindy and Abdel-Raouf (6.10 mm) in adult Egyptians, and Singh (6.16 ± 1.8 mm) in Indian skulls (Table 4) [5,11—14]. The present study results were lower than that of Chung et al. (8.60 mm) in Korean skulls, Canan et al. (8.30 mm in females, 10.9 mm in males), Kazkayasi et al. (7.19 mm), Agthong et al. (7.8 to 8.0 mm) in Asian adults, Apinhasmit et al. (9.23 ± 2.03 mm) in Thai adult skulls [1,2,15—17]. The present study showed no statistically significant differences in the distance between infraorbital foramen and infraorbital margin on right and left sides unlike few authors. The distance of infraorbital foramen from supraorbital foramen was found to be 42.02 ± 4.31 mm in our study (Table 1) while Chung et al. measured this distance to be 45.6 mm in Korean skulls [16].
Table 4 Comparison of mean distance between infraorbital foramen and infraorbital rim with other studies. Comparaison de la distance moyenne entre le foramen infraorbitaire et la bordure infra-orbitaire avec d’autres études. Study
Mean distance (mm)
Kazkayasi et al. Hindy and Abdel-Raouf Chung et al. Esper et al. Karakas et al. Macedo et al. Present study
7.19 ± 1.39 6.1 ± 2.4 8.60 6.80 6.7 6.37 6.71 ± 1.11
The infraorbital foramen was 31.94 ± 4.88 mm from the midsagittal plane (Table 1) which is much higher than the results of the study of Chung et al. in Korean skulls (27.2 mm) [16]. Aziz et al. reported this distance to be 27.9 mm (right), 27.5 mm (left) in men and 25.5 mm (right), 26.9 (left) in women [18]. The position of infraorbital foramen was lateral to supraorbital foramen in most cases (88%) in the present study (Table 2) which was much higher than the findings of Chung et al. (63.6%) and that of Aziz et al. (40% in men, 33% in women) [16,18]. The infraorbital foramen was more commonly situated above the 1st premolar tooth (44% in left side, 55% in right side) in the present study which was comparable with the study of Aziz et al. (64%) [18]. The knowledge of these morphometric variations of infraorbital foramen is significant for local anesthetic procedures and blockage of infraorbital nerve [8,19]. The approximate position of the infraorbital foramen helps us to determine the location of the infraorbital plexus which as mentioned by Hwang and Biak is a risk zone while performing plastic surgery [7]. This information about the interindividual anatomic variability of the infraorbital region helps in reducing the risks of procedural neurovascular (iatrogenic) injuries due to presence of additional branch of infraorbital nerve in surgeries such as those of anterior and superior walls of maxilla (maxillofacial surgery), rhinoplasty, surgeries of orbital floor, type I Le Fort osteotomies and various procedures involving intra- and extra-oral anesthesia [8,12,20,21]. The knowledge about variations in the position of IOF also becomes significant for techniques involving regional block anesthesia and for acupuncture used for treatment of trigeminal neuralgia [10,16,22]. The 2nd division of trigeminal nerve is an important potential pathway for perineural spread of malignancy. Imaging is a primary method for its detection. Normal appearance of infraorbital foramen shows fat pads and obliteration of this fat pad indicates spread of tumor in this canal. Therefore while doing tomographic studies for planning surgical resection or identifying target region for radiation therapy, infraorbital foramen can be identified by detection of these fat pads [23]. Accessory foramen was found in 11.2% cases (double foramen) in our study. It was comparable with study by Singh (10% more than 1 foramen) in Indian skulls, Canan et al. (11.5% single accessory foramen) and Elias et al. (10% in Brazilian skulls) [3,5,15]. The incidence of accessory foramen observed was lower in studies of Agthong et al. (3.6% in right, 4.5% left), Apinhasmit et al. (3.3% in Thai skulls), Kazkayasi et al. (5.7%) [1,2,4]. The knowledge of presence of accessory foramens is also essential during anesthesia, as the amount used may be inappropriate due to additional branch of infraorbital nerve in these foramens. Previous studies have also analysed the anatomical variations using different reference points in different population groups. Our study becomes relevant in the present study group as very scant data is available about the variations and morphometric measurements in Indian population. The data thus obtained will perhaps be helpful to the surgeons in identifying the extent of the operative field thereby reducing procedural risks.
Please cite this article in press as: Dixit SG, et al. Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population. Morphologie (2014), http://dx.doi.org/10.1016/j.morpho.2014.02.008
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Morphometric analysis and anatomical variations of infraorbital foramen
Conclusion The results when compared with previous studies show a large amount of variation in the anatomical position of IOF in relation to different reference points which is due to a diversity of investigated populations. As the data is dependent on population groups, therefore the present study becomes relevant as scant data is available in Indian population. These results can play a role in preventing the iatrogenic injuries during procedures involving the infraorbital region.
[10]
[11]
[12]
[13]
Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
[14] [15]
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Please cite this article in press as: Dixit SG, et al. Morphometric analysis and anatomical variations of infraorbital foramen: A study in adult North Indian population. Morphologie (2014), http://dx.doi.org/10.1016/j.morpho.2014.02.008
