Normative Measurement of Ocular Muscle Using Computed Tomography
DOI:
https://doi.org/10.63682/jns.v14i32S.7410Keywords:
Ocular Muscle (OM), Computed Tomography (CT), Extraocular Muscles (EOMs), Orbital Measurements (OMeas), Medial Rectus (MR), Lateral Rectus (LR), Inferior Rectus (IR), Ocular Diameter (OD), Lens Density (LD), Right and Left Eye Comparison (RLEC), Age and GAbstract
Accurate assessment of extraocular muscle dimensions is crucial for diagnosing orbital and systemic pathologies. Computed Tomography (CT) offers high-resolution imaging for precise measurement of orbital structures. This study aims to establish normative values for the diameters of extraocular muscles in a healthy population using CT imaging and to evaluate variations based on age, gender, and laterality. A prospective analysis was conducted on CT head scans of 118 individuals without orbital pathology. Measurements included diameters of the medial, lateral, inferior rectus, and superior muscle groups for both eyes. The study establishes normative CT-based ocular muscle dimensions, providing a reference for clinical assessment in the Indian population.
Downloads
Metrics
References
Schulz RA, Stein JA, Pelc NJ. How CT happened: the early development of medical computed tomography. J Med Imaging (Bellingham). 2021 Sep;8(5):052110. doi: 10.1117/1.JMI.8.5.052110. Epub 2021 Oct 29. PMID: 34729383; PMCID: PMC8555965.
Al-Naser YA, Tafti D. CT Instrumentation and Physics. [Updated 2023 Nov 2]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK597347/
Curry, T. S., Dowdey, J. E., & Murry, R. E. (1990). Christensen’s physics of diagnostic radiology (4th ed.). Lea & Febiger.
Hermena S, Young M. CT-scan Image Production Procedures. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK574548/
Chaurasia, B. D. (2019). BD chaurasia’s human anatomy, volumes 3 & 4: Regional and applied dissection and clinical: Head and neck, and brain-neuroanatomy (8th ed.). CBS Publishers & Distributors.
Ominde, B. S., Abadom, G. E., Ikubor, J. E., Achapu, L. C., Enakpoya, P. O., & Igbigbi, P. S. (2024). Normal diameter of the optic nerve using magnetic resonance imaging: A retrospective Nigerian study. Saudi Journal of Ophthalmology: Official Journal of the Saudi Ophthalmological Society, 38(1), 53–58. https://doi.org/10.4103/sjopt.sjopt_189_23
Almus E, Sen Akova B, Ozer H, Fitoz S. Orbital structures in the pediatric age group: A normative assessment using magnetic resonance imaging. Eur J Radiol. 2022 Sep;154:110418. doi: 10.1016/j.ejrad.2022.110418. Epub 2022 Jun 24. PMID: 35772338.
Rana, K., Juniat, V., Rayan, A., Patel, S., & Selva, D. (2022). Normative measurements of orbital structures by magnetic resonance imaging. International Ophthalmology, 42(12), 3869–3875. https://doi.org/10.1007/s10792-022-02407-1
Al Ajmi, E., Al Subhi, M., Al Maamari, M., Al Dhuhli, H., & Sirasanagandla, S. R. (2023). Radiologic Assessment of Orbital Dimensions among Omani Subjects: A computed tomography imaging-based study at a single tertiary centre. Sultan Qaboos University Medical Journal, 23(1), 55–60. https://doi.org/10.18295/squmj.3.2022.023
Rana K, Juniat V, Yong W, Patel S, Selva D. Normative orbital measurements in an Australian cohort on computed tomography. Orbit. 2023 Feb;42(1):68-72. doi: 10.1080/01676830.2022.2037143. Epub 2022 Mar 2. PMID: 35232320.
Boruah, D. K., Dutta, H. K., Sarma, K., Hazarika, K., Sharma, B. K., & Goswami, A. (2021). Normative magnetic resonance imaging measurements of orbital structures in pediatric population of North-Eastern India: A retrospective cross-sectional study. Indian Journal of Ophthalmology, 69(8), 2099–2105. https://doi.org/10.4103/ijo.IJO_546_21
Velonakis, G., Papadopoulos, V. E., Karavasilis, E., Filippiadis, D. K., & Zouvelou, V. (2021). MRI evidence of extraocular muscle atrophy and fatty replacement in myasthenia gravis. Neuroradiology, 63(9), 1531–1538. https://doi.org/10.1007/s00234-021-02753-4
Gala, F. (2015). Magnetic resonance imaging of optic nerve. The Indian Journal of Radiology & Imaging, 25(4), 421–438. https://doi.org/10.4103/0971-3026.169462
Ozdikici, M., Bulut, E., & Agca, S. (2021). Assessment of the orbital structures using computed tomography in healthy adults. Nigerian Journal of Clinical Practice, 24(4), 561–568. https://doi.org/10.4103/njcp.njcp_77_20
Keene, K. R., van Vught, L., van de Velde, N. M., Ciggaar, I. A., Notting, I. C., Genders, S. W., Verschuuren, J. J. G. M., Tannemaat, M. R., Kan, H. E., & Beenakker, J.-W. M. (2021). The feasibility of quantitative MRI of extra-ocular muscles in myasthenia gravis and Graves’ orbitopathy. NMR in Biomedicine, 34(1), e4407. https://doi.org/10.1002/nbm.4407
Yoo, R.-E., Park, S.-W., Rhim, J. H., Kim, J. E., Kim, S. C., Choe, J.-Y., Choung, H.-K., Khwarg, S. I., Kim, J.-H., Lee, J. H., Lee, B. E., & Kang, Y. (2020). CT and MR imaging findings of ocular adnexal mucosa-associated lymphoid tissue lymphoma associated with IgG4-related disease: multi-institutional case series. International Journal of Ophthalmology, 13(8), 1231–1237. https://doi.org/10.18240/ijo.2020.08.08
Rokka, D., Poudel, S., Kayastha, P., Suwal, S., Poudyal, S., Chhetry, S., Shrestha, S., & Karn, R. (2020). Normative measurement of orbital structures in computed tomography. Journal of the Institute of Medicine, 42(3), 42–46. https://doi.org/10.3126/jiom.v42i3.37580
Normative Orbital Measurements By Computed Tomography In North Indian Population - A Retrospective Study.
Willett KL, Sheng M, Gorry T, Woo JH. Quality of CT Imaging of Periocular Metallic Foreign Bodies Using Artifact Reduction Software. Ophthalmic Plast Reconstr Surg. 2019 Sep/Oct;35(5):438-443. doi: 10.1097/IOP.0000000000001295. PMID: 30688722.
Gupta, V., Prabhakar, A., Yadav, M., & Khandelwal, N. (2019). Computed tomography imaging-based normative orbital measurement in Indian population. Indian Journal of Ophthalmology, 67(5), 659. https://doi.org/10.4103/ijo.ijo_1187_18
MeasurementoftheOrbitalSoftTissueVolumeinChineseAdults Based on Three-Dimensional CT Reconstruction. (n.d.).
Xu, L., Li, L., Xie, C., Guan, M., & Xue, Y. (2017). Thickness of extraocular muscle and orbital fat in MRI predicts response to glucocorticoid therapy in Graves’ ophthalmopathy. International Journal of Endocrinology, 2017, 3196059. https://doi.org/10.1155/2017/3196059
Khademi, Z., & Bayat, P. (2016). Computed tomographic measurements of orbital entrance dimensions in relation to age and gender in a sample of healthy Iranian population. Journal of Current Ophthalmology, 28(2), 81–84. https://doi.org/10.1016/j.joco.2016.03.002
Pitceathly, R. D. S., Morrow, J. M., Sinclair, C. D. J., Woodward, C., Sweeney, M. G., Rahman, S., Plant, G. T., Ali, N., Bremner, F., Davagnanam, I., Yousry, T. A., Hanna, M. G., & Thornton, J. S. (2016). Extra-ocular muscle MRI in genetically-defined mitochondrial disease. European Radiology, 26(1), 130–137. https://doi.org/10.1007/s00330-015-3801-5
Zhang, Z.-H., Chen, Y., Wang, Y., Meng, W., Fang, H.-Y., Xu, D.-D., & Jin, Z.-Y. (2013). Normative measurements of extraocular musculature by multislice computed tomography. Chung-Kuo i Hsueh k’o Hsueh Tsa Chih [Chinese Medical Sciences Journal], 27(4), 232–236. https://doi.org/10.1016/s1001-9294(13)60007-3
Dhanwate, A. D., Associate Professor, Department of Anatomy, Government Medical College, Akola, Maharashtra, India (Former- Assistant Professor, Department of Anatomy, Government Medical College, Aurangabad, Maharashtra, India)., Gaikwad, M. D., & Lecturer, Department of Pathology, CSMSS Ayurved College, Aurangabad, Maharashtra, India. (2016). Morphometric analysis of orbit in Indian skulls and comparison with international studies. International Journal of Anatomy and Research, 4(4.1), 2896–2901. https://doi.org/10.16965/ijar.2016.363
Li R, Xia S, Wang J, Sun F, Qi J. [MRI study of the thickness and width of the extraocular muscles in normal subjects]. Zhonghua Yan Ke Za Zhi. 2015 Jun;51(6):434-8. Chinese. PMID: 26310117
Downloads
Published
How to Cite
Issue
Section
License

This work is licensed under a Creative Commons Attribution 4.0 International License.
You are free to:
- Share — copy and redistribute the material in any medium or format
- Adapt — remix, transform, and build upon the material for any purpose, even commercially.
Terms:
- Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
- No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.