Morphometric Study of Orbit in Skull Bones: Direct Measurement Study
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OriginalArticle IndianJournalofAnatomy Volume9Number1,January–March2020 DOI:http://dx.doi.org/10.21088/ija.2320.0022.9120.7 MorphometricStudyofOrbitinSkullBones:DirectMeasurementStudy ChakkaSreekanth1,LattupalliHema2 Howtocitethisarticle: ChakkaSreekanth,LattupalliHema.MorphometricStudyofOrbitinSkullBones:DirectMeasurementStudy.IndianJAnat. 2020;9(1):45-53. Author’s Affiliation: 1Associate Professor, Dept. of Anatomy, Sri Padmavathi College For Women (SVIMS), Tirupathi, Andhra Pradesh517507,India.2ProfessorandHeadofAnatomy,NarayanaMedicalCollege,Chinthareddypalem,Nellore,Nellore,Andhra Pradesh524003,India. CorrespondingAuthor:LattupalliHema,ProfessorandHead,Dept.ofAnatomy,NarayanaMedicalCollege,Chinthareddypalem, Nellore,AndhraPradesh524003,India. E-mail:hemakarra06@gmail.com Received19.10.2019|Accepted13.11.2019 Abstract orbitalcavityisessentiallyintendedasasocketfor the eyeball and also contains associated muscles, The essential segments of the skeleton are the nerves, vessels and in essence lodges the visual human skull and cranium which have received apparatus. This is an anatomical region which is significantattentioninforensicresearchespeciallyin ofclinicalandsurgicalinteresttomanydisciplines theanalysisofethno-racialrelationship.Thefeatures likeophthalmology,oralandmaxillofacialsurgery withinit(exampleorbit)maygivefurtherinsightinto theunderstandingofthecraniofacialanthropometry. andneurosurgery. Understanding the structural disposition of the In the adult human, the orbits are four sided human body is aided by the advances in medical pyramidal cavities: Its base opens into the face imaging techniques such as radiography, MRI, and has four borders, superior margin: frontal CT scan etc. But direct measurement on dry skulls bone, Inferior margin: maxilla and zygomatic, is a more natural perspective in assessing the orbitalcavities. Medial margin: frontal,lacrimalandmaxilla, and Lateral margin: zygomatic and frontal. Its apex Conclusion: Periorbital and facial injuries are is pointing back into the head and lies near the mainlycausedbyassaultsandfallsandattimesmay involvetheforehead.Suchinjuriesnecessitatecranial medialendofsuperiororbitalssureandcontains and orbital reconstructions to correct both esthetic the optic canal which communicates with middle andfunctionaldeficits.Caremustbetakentoprevent cranialfossa.Sevenbonesmakeupthebonyorbit: damagetotheneurovascularstructurescontainedin Frontal (Pars orbitalis), Lacrimal bone, Ethmoid theorbitorwithinitswalls.Inordertoachievethis, bone (Lamina papyracea), Zygomatic bone thesurgeonneedstohaveaproperunderstandingof (Orbitalprocessofthezygomaticbone),Maxillary thehumanorbitalstructure,itsrelationshipwithboth bone (Orbital surface ofthe body of the maxilla), intra-andextracranialstructures,andassociatedkey Palatine bone (Orbital process of palatine bone), surgicalandanatomicallandmarks. and Sphenoid bone (Greater and lesser wings). Keywords:Orbit;Shapes;Length;Orbitalindex. Theorbitisabonypyramidwithfourwalls:aroof, lateralwall,oor,andmedialwall.Thebaseofthe pyramidis the orbital entrance, which is roughly Introduction rectangular.Itmeasures4cmwideby3.5cmhigh and is rotated laterally. Because of this lateral Thetwoorbitalcavitiesaresituatedoneitherside rotation,thelateralorbitalrimisapproximatelyat ofthesaggitalplaneofskullbetweenthecranium theequatoroftheglobe,makingthegloberelatively and the skeleton of the face. Thus situated, they exposedlaterally.Theapexoftheorbitalpyramid encroachaboutequallyonthesetworegions.Each issituated44–50mmposterior.Themedialorbital ©RedFlowerPublicationPvt.Ltd. 46 ChakkaSreekanth,LattupalliHema/MorphometricStudyofOrbitinSkullBones: DirectMeasurementStudy wallsareparallel,approximately2.5cmapartand 4. To compare this study with previous separated by paired ethmoid sinuses. The orbital studies. volumeisroughly30ml,ofwhich7mlisoccupied 8 by the globe (Standring S, 2005). Also, since the MaterialsandMethods orbitisdevelopedaroundtheeye,ithasatendency towards being spheroidal in form, and its widest Osteometric study was done using 100 bones partisnotattheorbitalmarginbutabout1.5cm, obtained from the Department of Anatomy, behindthis.Patniaketal.(2001)3statedthatineach Narayana Medical College, Nellore and also Sri orbitalcavity,thewidthisusuallygreaterthanthe PadmavathiMedicalCollegeforWomen(SVIMS) height, the relation between the two is given by Tirupathi. the orbital index, which varies in different races (OrbitalIndex =Orbital Height/Orbital Breadth). The materials required for the study were Taking the orbital index as the standard, three thread, metallic scale and vernier calipers. Two classesoforbithavebeendescribed. measurements were made for each parameter to getanaveragevalueThemethodsemployedwere CT has revolutionized the diagnosis and accordingto(MekhlaD2012): management of ocular and orbital diseases. Theuseofthinsectionswithmultiplanarscanning 1. Inthecaseofshapebothsidesorbitswere and the possibility of 3-D reconstruction permits visualized assessed to determine whether thorough evaluation. Quantication of eye and squareorround. orbit anthropometric variation within the normal 2. The Perimeter (Pm) of the orbit was population is important for prediction and measured by pressing a loop of thread preventionofeyeinjury.WithCTimages,accurate alongtheoutermarginoforbit.Thethread measurementscanbecollectedforbonystructuresof wasthenmeasuredonametallicscaleand theorbitthatsurroundandprotecttheeye.Accurate thereadingswerenoted. measurementsofeyeandorbitanthropometryare 3. TheHeightoftheorbit(Ht)wasmeasured valuableinthedesignofeyeprotectiveequipment asthedistancebetweenthemidpointofthe andmodelingoffacialimpactsforinjuryprediction upperandlowermarginsoforbitalcavity. purposes.(AshleyAetal.,2010).7 4. Breadth(Br)oftheorbitwasmeasuredas Not many studies have been done pertaining the distance between the midpoint of the to morphometry of orbit in Indian population medial and lateral margin of the orbit by especiallyinsouthIndianskulls.Hence,thisstudy usingmanualverniercalipers. ofmorphometryoforbitinskullsbecomesessential 5. Orbital Index wasmeasuredbyusingthe to develop a database to determine normal orbit followingformula: valuesinSouthIndianpopulation. OrbitalIndex=Orbitalheight/Orbitalbreadth× 100. AimsandObjectives Takingtheorbitalindexasstandard,threeclasses Thisstudyisaimedatevaluatingthemorphology oftheorbitwererecognized: and morphometry of orbit related to gender and side wise in South Indian population and to get 1. Megaseme(Large):Theorbitalindexis89 normative/baselinedataregardingorbit. orover. 1. To study the morphology and 2. Messeme (Intermediate): Orbital index morphometryoforbitintheskullsthatis between89. segregatedaccordingtogender. 3. Microseme(Small):Orbitalindex83orless. 2. This study employs the use of direct 4. Lengthofthelateralwalloftheorbitwas measurementondryskullsasitwillpresent measuredfromthemidpointofthelateral adifferentandamorenaturalperspective marginoftheorbittotheapexoftheorbit inassessingtheorbitalcavities. using a thick strip of paper. The length 3. The parameters taken for this study are of the paper was then measured using shape of the orbit, perimeter, height, metallicscaleandverniercalipers. breadth,lengthofthelateralwall,medial 5. Lengthofthemedialwalloftheorbitwas wall, roofand oor.Intra orbitaldistance measured from the midpoint of medial andextraorbitaldistance. walloftheorbittotheapexoftheorbit. IndianJournalofAnatomy/Volume9,Number1/January–March2020 ChakkaSreekanth,LattupalliHema/MorphometricStudyofOrbitinSkullBones: 47 DirectMeasurementStudy 6. Roof length of the orbit was measured reported that the Orbit had two shapes round from the midpoint of the upper margin and square. In females the round percentage oftheorbittotheapexoftheorbit.7Floor being 72% and square being 28%. In males Lengthoftheorbitwasmeasuredfromthe squareshapewasseenin80%androundshape midpointofthelowermarginoftheorbit was seen in 20% of the skulls. In the present totheapexoftheorbit. studyinmalessquareshapewasseenin66.7% 7. Intra orbital distance was measured and round shape in 33.3%. In females square betweenthemidpointsofmedialmargins shape was seen in 30.2% and round shape in ofmedialoftwoorbits. 69.8% respectively (Fig. 6, Table 1). There is a difference in the percentages in present and 8. Extra orbital distance was measured previousstudies.Thesevariationsmaybedueto, between the midpoints of lateral margins interobservervariationsorsmallsamplesizein oftwoorbits. the previous study or racial differences seen in SouthAfricanpopulation. ResultsandDiscussion The orbits are paired structures, located on the anteriorpartofthefaceandprotectedbythelids. Eachorbitcanbecomparedtoatinyjewelboxthat hasvery precious contents,all carefully wrapped in fatty tissue. Morphologically, each orbit is a four sided pyramid with a posterior apex and anteriorbase.Knowledgeoftheorbitalosteologyis paramountinadequatelychoosingandperforming an orbital approach. Understanding the critical topographicalelementsinthisareahelpstoclassify an orbital lesion and provides a solid basis in choosingthemostadequateintraorbitalroutefor thetreatment(Fig.1). Shapeoftheorbit E Pretorious et al. (2006)11intheirstudyfound twoshapesoftheorbitnamelysquarewhichwas OC-Opticcanal,LWL-Lateralwalllength,MWL-Medialwall 73.33%inmalesandroundwhichwas26.77%,in length femalesthesquareshapewasobservedin2%and the round shapewas observed in 80%. A study done by Mekhala D (2014)20 in her study also Table1:Comparisonoftheshapeoforbitinmaleandfemaleskulls Male Female Shape