International Journal of Morphology
versión On-line ISSN 0717-9502
Int. J. Morphol. v.25 n.2 Temuco jun. 2007
Int J. MorphoL, 25(2):301-304, 2007.
Morphometric Analysis of Infraorbital Foramen in Human Foetuses
Análisis Morfométrico del Foramen Infraorbital en Fetos Humanos
*Ghaus Farah & **Faruqi N. A.
* Senior Resident, MBBS, MD, Department of Anatomy, J N Medical College, Aligarh Muslim University, Aligarh, India.
SUMMARY: A detailed knowledge of the anatomic morphometry of infraorbital groove, canal and foramen was necessary for a surgeon while performing maxillofacial surgery and regional block anaesthesia. Modern surgical procedures as well as anaesthesia require more precise understanding of the surrounding anatomy. The aim of the study was to establish morphometrically the infraorbital foramen size and location in human foetuses, the area where this information was scanty. Sixty maxillae were dissected out from thirty human foetuses. The latter were divided into five groups on the basis of age i.e. groups I(<17 weeks IUL),II (17-20 weeks IUL), III (21-25 weeks IUL),IV (26-30 weeks IUL) and V (>30 weeks IUL). Four parameters including transverse diameter and vertical diameter of infraorbital foramen and its distances from the infraorbital margin and nasal notch, were considered. Foramen was nearly circular in group I foetuses (transverse as well as vertical diameter being 0.6 mm approximately) but in subsequent groups,the foramen is transversely oval due to faster increase in transverse diameter (1.93 mm in group V whereas the vertical diameter in group V remained 1.21 mm only). Downward displacement was found to be relatively more than the lateral displacement. Third group showed maximum increase in all the four parameters. Some association between diameter of infraorbital foramen and foetal age was established on the basis of correlation coefficient analysis.
KEYWORDS: Infraorbital foramen; Morphometry; Human foetuses; Maxilla; Development.
RESUMEN: Conocer en detalle la anatomía y morfometría de la incisura, canal y foramen infraorbitales, es importante para los crujanos maxilofaciales en el bloqueo anestésico regional. Modernos procedimientos quirúrgicos, como también anestésicos, requieren un conocimiento más preciso de la anatomía de esa zona. El objetivo de este estudio fue establecer mofológicamente el tamaño y la localization de estas estructuras, en fetos humanos, área en la cual existe insuficiente información. Fueron disecados 60 maxilares, de 30 fetos humanos. Los fetos fueron divididos en cinco grupos basados en la edad: Grupo I (<17semanas VIU), II (17-20 semanas VIU), III (21-25 semanas VIU), IV (26-30 semanas VIU) y V (>30 semnaas VIU). Fueron considerados cuatro parámetros, incluyendo diámetros transverso y vertical del foramen infraorbital y sus distancia entre el margen infraorbital y la incisura nasal. El foramen infraorbital era aproximadamente circular en el Grupo I de fetos (tanto el diámetro transverso como el diámetro vertical medían 0,6 mm, aproximadamente) pero en los grupos subsecuentes, el foramen infraorbital era oval transversalmente, incrementándose el diámetro transversal (1,93 mm en el Grupo V y solamente 1,21 mm de diámetro vertical en este mismo grupo). Relativamente, el foramen infraorbital se desplazaba más hacia abajo que hacia lateral. El Grupo III mostró un máximo incremento en los cuatro parámetros. Fueron establecidas algunas asociaciones entre el diámetro del foramen infraorbital y la edad fetal, basándose en el análisis de coeficiente de correlación.
PALABRAS CLAVE: Foramen nfraorbital; Morfometría; Fetos humanos; Maxila; Desarrollo.
Importance of infraorbital foramen lies in the fact that the site is used for infraorbital nerve blocking to anaesthetize the upper jaw for surgical purposes in adult. Kazkayasi et al (2001,2003) provided detailed information about the variations of infraorbital foramen in terms of its shape, number and locations. Precise location of infraorbital foramen was so much necessary that enormous literature were made available in different races world wide (Hwang & Baik, 1999; Lee et al, 2006; Elias et al, 2004; Hindy & Abdel-Raouf, 1993). Recently various invasive and non invasive approaches aimed at correction of different foetal defects had led to the emergence of a highly promising superspeciality of foetal therapy. Foetal repair of the congenital diaphragmatic hernia was technically made possible by Soper (1984). McKinstry (1987) for the first time established correlation between location of the anterior end of infraorbital canal and cleft palate. Such correlation has further enhanced the scope of study on foetal anatomy. Although attempts have been made to collect informations about morphometry of maxilla in adults (Bachereia et al., 2000) but detailed morphometric data on foetal anatomy in general during intrauterine life was scanty in literature. The aim of the present study was to find out the accurate foetal anatomy of infraorbital foramen and establish the exact pattern ofits growth which might reflect informations about its postnatal anatomy both normal and abnormal.
MATERIAL AND METHOD
Sixty dissected and isolated maxillae were used for the study. Ages of foetuses ranged from 16 weeks to 34 weeks of intrauterine life(IUL). Foetuses were divided into five groups according to age (Table I). Periosteum and soft tissue adherent to the anterior surface of maxilla were carefully removed under dissecting microscope to visualize the infraorbital foramen, infraorbital margin and infraorbital notch (Fig. 1). Transverse and vertical diameters of the infraorbital foramen and its distance from the nearest point of infraorbital margin and nasal notch were measured with the help of Vernier callipers under dissecting microscope (Tables II, IV, VI and VII). To find out the growth between adjacent foetal groups, Student's 't' test was used. To establish the association between diameters of foramen and growth of foetus, correlation coefficient between two variables in different groups were calculated.
RESULTS AND DISCUSSION
Invariably all sixty maxillae under observation showed presence of infraorbital foramen. Patnaik et al (2001) had reported presence of infraorbital notch at times in adult. It is indicative of continued osteoclastic activity in late foetuses or after birth. Correct location of infraorbital foramen had long been the subject of interest. In all previous reports, infraorbital margin and anterior nasal aperture were considered as landmarks of reference. Reported average distances of infraorbital foramen from infraorbital margin were far variable in adults i.e. 4-12 mm (Elias et al.; Wolff, 1954; Limke & Lukarelli, 1998; Kazkayasi etal, 2001;Hindy & Abdel-Raouf, 1993 and Chung et al, 1995). Variations are attributed to individual precision, race and material and methods used. It is also indicative of variable postnatal osteoblastic and osteoclastic activity in different individuals. A steady downward shift of infraorbital foramen in relation to infraorbital margin was a constant feature in our observations (Table VI) but with variable rates, being maximum in group II. Maximum distance of 2 mm was found in last group. The measurement increases greatly, as expected, to make it 4 mm or more in adults. Limke & Lukarelli provided only vague information in children about its distance from infraorbital margin. According to them, infraorbital foramen was present just below the infraorbital margin but did not mention the exact distance. In adult,they have reported it to be 6 mm. To find out the shift of foramen in relation to midline, nearest distance between nasal notch and infraorbital foramen was measured. It was found to be approximately 3 mm in first group which increased to 6 mm in last group (Table VII). Kazkayasi et al. (2001) mentioned in adult, the distance of foramen from notch in horizontal plane to be 7 mm approximately. Value of nearest distance from the notch will be naturally further less. Above informations clearly indicate that osteoblastic activities involve maximally the region between infraorbital foramen and infraorbital margin and it is minimal between foramen and notch. In our findings, there was tendency of infraorbital foramen to be transversely oval during intrauterine life, a feature more prominent in subsequent groups (Tables II and IV). It was interesting to note that foramen was invariably single in all the specimens. Kazkayasi etal (2003) described more than one foramen in 10 per cent adult cadavers. Same group of authors (2001) observed different shapes of infraorbital foramina in human skulls. It was oval in only 34 per cent cases, in rest it was either round or semicircular. Aforementioned informations regarding the number and shapes of foramina in postnatal life indicated continued osteoblastic and osteoclastic activities afterbirth. Correlation co-efficient analysis established some association between transverse and vertical diameters and foetal age in all the groups except group I which showed no association (Tables III and V). The latter phenomenon established little or no osteoblastic or osteoclastic activities in the region before 17 weeks of intrauterine life.
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Received: 02-12-2006 Accepted: 26-02-2007