The prevalence of anatomical variations in the intraorbital part of the ophthalmic artery and its branches in cadavers

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Date
2017
Authors
Mpolokeng, Kentse Sana
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University of the Free State
Abstract
English: The human orbit contains various important structures that may show variations relating to their anatomy. This study focused on the intraorbital part of the ophthalmic artery in a South African cadaver sample in the Free State (UFS) and Western Cape provinces (UCT). Meyer pioneered the study of the ophthalmic artery as far back as 1887, with a main focus on its branches and their variations. Very limited investigation has been carried out in this field and available literature has little information on this. Currently no published data exists on the South African population with regard to intraorbital variations within the ophthalmic artery and its branches. Original research was conducted to address the problem of the lack of data. Dissections of the eyes were done to investigate and document the possible variations of the intraorbital part of the ophthalmic artery and its branches. The aim of the study was to determine the prevalence of anatomical variations in the intraorbital part of the ophthalmic artery and its branches in a cadaver sample. The results of the study will be of value to surgical interventionists treating patients with vascular diseases within the orbital region and also to the ophthalmology students studying the orbital vascular anatomy. A total number of 59 cadavers were utilised, and 118 eyes were dissected under the lighted magnifier and observed for variations. The sample consisted of 23 cadavers (46 eyes) from the Department of Basic Medical Sciences of the University of the Free State, and 36 cadavers (72 eyes) from the Department of Human Biology of the University of Cape Town. Sixteen types of variations were observed and documented. The ophthalmic artery crossed below the optic nerve in the left eye in 7.63% of cadavers at both institutions. No ophthalmic artery crossed below the optic nerve in the right eye in the UCT group, whereas 17.39% in the UFS group crossed below the optic nerve. Statistical analyses determined the frequencies of the variations. In certain individuals there were more than one type of variation which is in agreement with published literature. The majority of variations in branching patterns occurred bilaterally and in most cases, the variation in the left eye differed from the variation in the right eye. Males showed a higher frequency of variations. These findings may well contribute to clinical application in ophthalmology and radiology while it will also inform anatomy students studying the blood supply to the eye and surrounding structures.
Afrikaans: Die menslike oog bevat verskeie belangrike strukture wat moontlik variasies kan toon wat verband hou met hul anatomie. Hierdie studie fokus op die intraorbitale deel van die oftalmiese arterie in ʼn Suid-Afrikaanse kadawersteekproef in die Vrystaat (UV) en die Wes- Kaapse (UCT) provinsies. Meyer was alreeds in 1887 die voorloper van studies van die oftalmiese arterie en het veral gefokus op die vertakkings en hul variasies. Slegs beperkte ondersoeke op hierdie terrein is gedoen en beskikbare literatuur bevat min inligting oor die onderwerp. Tans is daar geen gepubliseerde data beskikbaar oor die Suid-Afrikaanse bevolking met betrekking tot intraorbitale variasies binne die oftalmiese arterie en sy vertakkings nie. Oorspronklike navorsing is gedoen om die probleem van die gebrek aan data aan te spreek. Disseksies van die oog is uitgevoer om die moontlike variasies van die intraorbitale deel van die oftalmiese arterie en sy vertakkings te ondersoek en te dokumenteer. Die doel van die studie was om die voorkoms van anatomiese variasies in die intraorbitale deel van die oftalmiese arterie en sy vertakkings in ’n kadawersteekproef te bepaal. Die resultate van die studie sal waardevol wees vir chirurge wat intervensies doen op pasiënte met vaskulêre siektetoestande binne die orbit en ook vir oftalmologiestudente wat die anatomie van die orbit bestudeer. In totaal is 59 kadawers bestudeer en 118 oë is gedissekteer onder ’n verligte vergrootglas, en die variasies is waargeneem. Die steekproef het bestaan uit 23 kadawers (46 oë) van die Departement Basiese Mediese Wetenskappe van die Universiteit van die Vrystaat (UV) en 36 kadawers (72 oë) van die Departement van Mensbiologie van die Universiteit van Kaapstad (UCT). Sestien tipes variasies is waargeneem en gedokumenteer. Die oftalmiese arterie van die linkeroog het in 7.63% van kadawers van beide instansies die optiese senuwee onder gekruis. Geen oftalmiese arterie het onder die optiese senuwee in die regteroog gekruis in die UCT groep nie, terwyl dit in 17.39% van die UV groep voorgekom het. Statistiese analises het die frekwensie van die variasies bepaal. By sommige individue was daar meer as een tipe variasie, wat in ooreenstemming is met bevindinge in gepubliseerde literatuur. Die meerderheid variasies in vertakkingspatrone het bilateraal plaasgevind en in die meerderheid gevalle het die variasie in die linkeroog verskil van die variasie in die regteroog. Manlike persone het ’n groter frekwensie van variasie vertoon. Hierdie bevindinge mag inderdaad bydra tot kliniese aanwending in oftalmologie en radiologie terwyl dit ook anatomiestudente wat die bloedtoevoer tot die oog en omliggende strukture bestudeer van inligting voorsien.
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Keywords
Ophthalmic artery, Optic nerve, Variation, Cadaver, UFS (University of the Free State), UCT (University of Cape Town), Intraorbital, Human orbit, Dissections, Dissertation (M.Med.Sc. (Anatomy and Cell Morphology))--University of the Free State, 2017
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