O R I G I N A L A R T I C L E
P. Karakas Æ M.G. Bozkır Æ O¨. Ogguz
Morphometric measurements from various reference points
in the orbit of male Caucasians
Received: 11 February 2002 / Accepted: 28 June 2002 / Published online: 18 December 2002
Ó Springer-Verlag 2002
Abstract The aim of this study was to determine the morphometric variations from various reference points to decrease risks in orbital surgery. Sixty-two orbits ob-tained from 31 skulls of male adult Caucasians were measured with a millimetric compass. On the medial orbital wall, the midpoint of the anterior lacrimal crest was the reference point; from this point we measured distances of 23.9±3.3 mm, 35.6±2.3 mm, 41.7± 3.1 mm and 6.9±1.5 mm respectively to the anterior ethmoidal foramen, posterior ethmoidal foramen, mid-point of the medial aspect of the optic canal and poste-rior lacrimal crest. On the same wall, distances from the plane of the anterior and posterior ethmoidal foramina to the ethmoido-maxillary suture and distance from the posterior ethmoidal foramen to the anterior ethmoidal foramen and midpoint of the medial margin of the optic canal were 14.9±2.3 mm, 9.8±2.9 mm and 6.8±2.2 mm respectively. On the inferior orbital wall, the main reference point was the infraorbital foramen, and from this point to the midpoints of the lateral margin of the fossa for the lacrimal gland, inferior orbital fissure, inferior orbital rim and inferior aspect of the optic canal was 23.8±7.2 mm, 31.9±3.9 mm, 6.7±1.9 mm and 50.3±3.2 mm respectively. On the superior orbital wall, the distances from the supraorbital foramen to the mid-points of the superior orbital fissure, fossa for the lacri-mal gland and superior aspect of the optic canal were 45.7±3.6 mm, 26.0±2.5 mm and 45.3±3.2 mm re-spectively. Furthermore, on the same wall, the distance from the posterior ethmoidal foramen to the midpoint of
the superior orbital fissure was 14.6±2.8 mm. Finally, on the lateral orbital wall the frontozygomatic suture was the reference point. From this point distances to the midpoints of the fossa for the lacrimal gland, superior orbital fissure, lateral aspect of the optic canal and inferior orbital fissure were 17.5±2.1 mm, 37.7± 3.6 mm, 44.9±2.5 mm and 33.4±3.1 mm respectively. The French version of this article is available in the form of electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00276-002-0071-0.
Etude morphome´trique de l’orbite d’hommes caucasiens base´e sur diffe´rents points de re´fe´rences
Re´sume´ Le but de cette e´tude e´tait de de´terminer les variations morphome´triques a` partir de diffe´rents points de re´fe´rence afin de diminuer le risque en chirurgie orbitaire. Soixante-deux orbites, obtenues a` partir de 31 craˆnes de sujets maˆles adultes caucasiens, ont e´te´ me-sure´es avec un compas millime´trique. Sur la paroi me´diale de l’orbite le milieu de la creˆte lacrymale ante´rieure e´tait le point de re´fe´rence ; a` partir de ce point ont e´te´ obtenues des mesures de 23,9±3,3 mm, 35,6±2,3 mm, 41,7±3,1 mm, 6,9±1,5 mm respective-ment pour le foramen ethmoı¨dal ante´rieur, le foramen ethmoı¨dal poste´rieur, le milieu du bord me´dial du canal optique et la creˆte lacrymale poste´rieure. Sur cette meˆme paroi, la distance entre le niveau des foramen eth-moı¨daux ante´rieur et poste´rieur et la suture ethmoı¨do-maxillaire, et la distance entre le foramen ethmoı¨dal poste´rieur et le milieu du bord me´dial du canal optique ont e´te´ trouve´es a` respectivement 14,9±2,3 mm, 9,8±2,9 mm, 6,8±2,2 mm. Sur la paroi infe´rieure de l’orbite, le principal point de re´fe´rence e´tait le foramen infra-orbitaire; a` partir de ce point ont e´te´ mesure´es respectivement les distances jusqu’aux milieux du bord late´ral de la fosse de la glande lacrymale, de la fissure orbitaire infe´rieure, du bord orbitaire infe´rieur et du bord infe´rieur du canal optique respectivement a` DOI 10.1007/s00276-002-0071-0
The French version of this article is available in the form of elec-tronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/ s00276-002-0071-0
P. Karakas (&) Æ M.G. Bozkır Æ O¨. Ogguz Department of Anatomy, C¸ukurova University, Faculty of Medicine, 01330 Adana, Turkey
E-mail: karakaspinar@hotmail.com/nboyan@cu.edu.tr Tel.: +90-322-3386060 ext. 3489
23,8±7,2 mm, 31,9±3,9 mm, 6,7±1,9 mm, 50,3± 3,2 mm. Sur la paroi supe´rieure de l’orbite, les distances a` partir du foramen supra-orbitaire jusqu’aux milieux de la fissure orbitaire supe´rieure, de la fosse de la glande lacrymale et du bord supe´rieur du canal optique ont e´te´ trouve´es respectivement a` 45,7±3,6 mm, 26,0±2,5 mm, 45,3±3,2 mm. De plus, sur cette meˆme paroi, la distance se´parant le foramen ethmoı¨dal poste´rieur et le milieu de la fissure orbitaire supe´rieure a e´te´ mesure´e a` 14,6±2,8 mm. Pour terminer, sur la paroi late´rale de l’orbite, la suture fronto-zygomatique e´tait le point de re´fe´rence. A partir de ce point, des mesures ont e´te´ re´alise´es jusqu’aux milieux de la fosse de la glande lacrymale, de la fissure orbitaire supe´rieure, du bord late´ral du canal optique et de la fissure orbitaire infe´ri-eure, trouve´es respectivement a` 17,5±2,1 mm, 37,7±3,6 mm, 44,9±2,5 mm et 33,4±3,1 mm.
Keywords Orbit Æ Bony walls of the orbit Æ Reference points Æ Morphometric measurements
Introduction
The orbit is an important anatomic landmark as it comprises the crossroads of the central nervous system
and connections with the nose, paranasal sinuses and face and also the structures related to the function of the eyeball [25]. Precise knowledge regarding the orbit will aid diagnosis, treatment planning and avoid loss of optic function [19]. This structure has four walls termed su-perior, inferior, medial and lateral, each of which pos-sesses distinctive clinical importance [18, 19, 27]. There are several reference points on each wall with respect to orbital, oral and maxillofacial surgery and local anes-thesia [1]. Modern surgical procedures to the orbit re-quire more precise understanding of the surrounding anatomy. Data on morphometric measurements re-garding reference points should reduce risks during surgical operations.
The purpose of this study was to conduct morpho-metric measurements of the orbit by using canals and foramina as reference points.
Materials and methods
To study the landmarks in the bony walls of the orbit, direct measurements were taken from dry Caucasian skulls. Skulls used were all in the collection of our department. These skulls were all determined by dentition to be from adult male Caucasians (aged 30–50 years). Sixty-two orbits (31 skulls) were studied. The mea-surements were made with a millimetric compass. All measure-ments were performed by the authors. The measuremeasure-ments on the bony walls of the orbit are shown in Figs. 1, 2, 3, 4. The program SPSS 9.0 was used in the statistical evaluation of measurement results. From these measurements means and standard deviations were calculated.
Results
The morphometric measurement results from the medi-al, inferior, superior and lateral walls of the orbit are shown in Tables 1, 2, 3, 4.
Fig. 1 Measurements of the medial orbital wall. A1, Distance from the midpoint of the anterior lacrimal crest to the anterior ethmoidal foramen; A2, distance from the midpoint of the anterior lacrimal crest to the posterior ethmoidal foramen; A3, distance from the midpoint of the anterior lacrimal crest to the midpoint of the medial aspect of the optic canal; A4, distance from the midpoint of the anterior lacrimal crest to the midpoint of the posterior lacrimal crest; B, distance from the plane of the anterior and posterior ethmoidal foramina to the ethmoido-maxillary suture; C1, distance from the posterior ethmoidal foramen to the anterior ethmoidal foramen; C2, distance from the posterior ethmoidal foramen to the midpoint of the medial margin of the optic canal
Discussion
The orbit is an important region because of its close association with the paranasal sinuses and because of the veins and nerves which pass through its foramina [25, 27]. Precise knowledge of the location of reference points in this area provides important data in local an-esthesia and in maxillofacial and plastic surgical opera-tions [1, 11, 19, 24].
The anatomy of the medial wall is important for successful results of some orbital procedures such as ethmoidal vessel ligation, medial wall fractures, orbital decompression, ethmoid sinus exenteration, transethm-oidal sphenoidotomy and transethmtransethm-oidal sphentransethm-oidal hypophysectomy. The anatomic landmark on this wall is
the anterior lacrimal crest. There are some individual variations in this crest. Thus surgically it is difficult to find the middle point of the lacrimal crest. The anterior ethmoidal artery was found beyond 2 cm from this point and the upper extent of the medial wall was constant. Fig. 2 Measurements of the inferior orbital wall. D1, Distance
from the infraorbital foramen to the midpoint of the lateral margin of the fossa for the lacrimal gland; D2, distance from the infraorbital foramen to the midpoint of the inferior orbital fissure; D3, distance from the infraorbital foramen to the midpoint of the inferior orbital rim; D4, distance from the infraorbital foramen to the midpoint of the inferior aspect of the optic canal
Fig. 4 Measurements of the lateral orbital wall. G1, Distance from the frontozygomatic suture to the midpoint of the fossa for the lacrimal gland; G2, distance from the frontozygomatic suture to the midpoint of the superior orbital fissure; G3, distance from the frontozygomatic suture to the midpoint of the lateral aspect of the optic canal; G4, distance from the frontozygomatic suture to the midpoint of the inferior orbital fissure
Table 1 Morphometric measurements (mm; mean±SD) of the medial orbital wall. A1, Distance from the midpoint of the anterior lacrimal crest to the anterior ethmoidal foramen; A2, distance from the midpoint of the anterior lacrimal crest to the posterior ethm-oidal foramen; A3, distance from the midpoint of the anterior lacrimal crest to the midpoint of the medial aspect of the optic canal; A4, distance from the midpoint of the anterior lacrimal crest to the midpoint of the posterior lacrimal crest; B, distance from the plane of the anterior and posterior ethmoidal foramina to the ethmoido-maxillary suture; C1, distance from the posterior ethm-oidal foramen to the anterior ethmethm-oidal foramen; C2, distance from the posterior ethmoidal foramen to the midpoint of the medial margin of the optic canal
A1 (44) 23.9±3.3 A2 (48) 35.6±2.3 A3 (51) 41.7±3.1 A4 (56) 6.9±1.5 B (52) 14.9±2.3 C1 (47) 9.8±2.9 C2 (52) 6.8±2.2
Fig. 3 Measurements of the superior orbital wall. E1, Distance from the supraorbital foramen to the midpoint of the superior orbital fissure; E2, distance from the supraorbital foramen to the midpoint of the fossa for the lacrimal gland; E3, distance from the supraorbital foramen to the midpoint of the superior aspect of the optic canal; F, distance from the posterior ethmoidal foramen
to the midpoint of the superior orbital fissure Table 2 Morphometric measurements (mm; mean±SD) of the inferior orbital wall. D1, Distance from the infraorbital foramen to the midpoint of the lateral margin of the fossa for the lacrimal gland; D2, distance from the infraorbital foramen to the midpoint of the inferior orbital fissure; D3, distance from the infraorbital foramen to the midpoint of the inferior orbital rim; D4, distance from the infraorbital foramen to the midpoint of the inferior aspect of the optic canal
D1 (41) 23.8±7.2
D2 (48) 31.9±3.9
D3 (51) 6.7±1.9
From clinical experience, the anterior ethmoidal fora-men and the area where the artery leaves the ethmoid medially are the most critical regions for frontobasal fractures [12]. During dissection the posterior ethmoidal foramen was found along the plane of the anterior ethmoidal foramen [19]. As noted by Caliot et al. [4] the variability of the anterior and posterior ethmoidal for-amina through which the ethmoidal vessels pass is also related to anterior cranial fossa surgery. The anterior ethmoidal artery is a key structure for this cranial fossa because it is attached to the skull base [14]. The anterior ethmoidal artery is also found in relationship with the bony medial wall of the orbit [8]. A third ethmoidal foramen was occasionally found (28% of skulls) that was called the middle ethmoidal foramen [27]. Kirschner et al. [13] had noted that it might be important to find all posterior ethmoidal vessels in surgery for epistaxis. Some bony defects of the anterior ethmoidal canal were observed in eight of 70 cases in a cadaveric study [16]. Surgical approach to this artery must be performed with great caution, as inadvertent injury to the artery may result in hemorrhage and orbital hematoma [14, 16, 22]. The optic canal is found behind the posterior ethmoidal foramen. The distance between the posterior ethmoidal foramen and the optic nerve is variable but not less than 3 mm [19]. This measurement was not less than 4.6 mm in our study. The measurements on the medial wall by Hwang and Baik [11] revealed the distance between the midpoint of the anterior lacrimal crest and posterior ethmoidal foramen as 32 mm in 41 dry Korean skulls. On the same wall, Rontal et al. [19] made morphometric measurements in 24 dry Indian skulls and found the distances from the midpoint of the anterior lacrimal crest to the anterior ethmoidal foramen, posterior ethmoidal foramen, midpoint of the medial margin of the optic canal and midpoint of the posterior lacrimal crest to be 24 mm, 36 mm, 42 mm and 8 mm respec-tively, whereas these measurements in our study were 24 mm, 35 mm, 41 mm and 7 mm respectively in 31 dry Caucasian skulls. Our results are more similar to Indian skulls than Koreans ones.
Orbital floor exploration and maxillectomy are the major operations along the inferior wall [7]. The first incision for these procedures is on the inferior orbital rim. In the study by Berry [3], who used skulls from different geographic locations, multiple foramina were
found in Mexicans. This may be important for surgeons because injury to any branch can result in sensory deficit and partial nerve blockade [24]. The number of infra-orbital foramina could sometimes be more than one and accessory foramina have been found in 2–18% of indi-viduals in various populations [3, 27]. On the inferior wall, Rontal et al. [19] found the distance between the infraorbital foramen and midpoint of the inferior orbital fissure to be 24 mm whereas Hwang and Baik [11] found it to be 26 mm. The distance between the infraorbital foramen and midpoint of the inferior orbital rim has been reported to be from 4 mm to over 10 mm in several studies [1, 5, 6, 9, 10, 15, 17, 20, 24, 26, 28]. In our study the measurement between the infraorbital foramen and midpoint of the inferior orbital rim was taken as 7 mm while the distance from the same point to the midpoint of the inferior orbital fissure was 32 mm. There were some differences on the inferior wall measurements between both Indian and Korean skulls and our skulls. Along the superior orbital wall, intraorbital opera-tions include frontal ethmoidectomy, orbital decom-pression, excision of the lacrimal gland and frontal sinus obliteration. The incisions must be placed to avoid the supraorbital nerve [2, 19]. A supraorbital notch or fo-ramen occurs equally in some populations. Berry [3, 27] studied the incidence of supraorbital foramina and notches. Anteromedially, near the junction of superior and medial walls, a trochlear fovea or spine is found where the superior oblique muscle is attached. When the posterior ethmoidal artery approaches the posterior ethmoidal foramen, it crosses this muscle. Ducasse et al. [8, 27] reported the artery crossed over the muscle in 50 of 70 cadavers. On the superior wall, Rontal et al. [19] reported the measurements from the supraorbital fora-men to the midpoints of the superior orbital fissure, fossa for lacrimal gland and superior aspect of the optic canal to be 40 mm, 32 mm and 45 mm respectively. In this study these measurements were 46 mm, 26 mm and 45 mm respectively. It is therefore considered that there are clear differences in the measurements of the superior wall between this study and Indian skulls.
The lateral wall is the guide to lateral orbitotomy and lacrimal gland excision [21, 23]. The landmark on this wall is the superior orbital fissure, through which pass the major orbital vessels and nerves with the exception of the optic nerve and ophthalmic artery [25, 27]. On the Table 3 Morphometric measurements (mm; mean±SD) of the
superior orbital wall. E1, Distance from the supraorbital foramen to the midpoint of the superior orbital fissure; E2, distance from the supraorbital foramen to the midpoint of the fossa for the lacrimal gland; E3, distance from the supraorbital foramen to the midpoint of the superior aspect of the optic canal; F, distance from the posterior ethmoidal foramen to the midpoint of the superior orbital fissure
E1 (57) 45.7±3.6
E2 (61) 26.0±2.5
E3 (54) 45.3±3.2
F (52) 14.6±2.8
Table 4 Morphometric measurements (mm; mean±SD) of the lateral orbital wall. G1, Distance from the frontozygomatic suture to the midpoint of the fossa for the lacrimal gland; G2, distance from the frontozygomatic suture to the midpoint of the superior orbital fissure; G3, distance from the frontozygomatic suture to the midpoint of the lateral aspect of the optic canal; G4, distance from the frontozygomatic suture to the midpoint of the inferior orbital fissure
G1 (60) 17.5±2.1
G2 (57) 37.7±3.6
G3 (52) 44.9±2.5
lateral wall, Rontal et al. [19] have reported the distance from the frontozygomatic suture to the midpoint of the superior orbital fissure to be 35 mm whereas Hwang and Baik [11] reported it to be 34 mm. This measurement was 38 mm in our study. This distance is suggested to be a safe distance and the dissection should be done with great caution.
The proximity of the paranasal sinuses and the presence of vessels predispose to neoplastic and inflam-matory disease of the contiguous sinuses [25].
When comparing similar studies in the literature with this study, on average there is a similarity between the medial and lateral wall measurements and the data from other studies. However, there are some differences in the results of some of the reference point measurements on the inferior and superior walls. We consider that the diversity could be a result of factors such as age, sex, race and differences in the reference points which are taken as criteria in the measurements.
Conclusion
We believe that data collected in this small but complex anatomic area are important, as precise morphometric measurements should increase success in surgical pro-cedures and avoid injury to the intraorbital structures.
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