Assessment of the Optic Foramen Shape and Size in Human Fetuses

This study was aimed to obtain data on the dimensions of the optic foramen in human fetuses for early childhood surgeries.

Twenty-five formalin-fixed fetuses (16 boys and 9 girls) with average age 21.68 ± 3.12 gestational weeks (range, 16-28 weeks) in the inventory of Anatomy Department, Faculty of Medicine were included in the study. The surface area, width, and height of the optic foramen were bilaterally measured using a digital image analysis software.

The forms of the optic foramen were described as oval shaped (72%, 36 foramina) and round shaped (28%, 14 foramina). The surface area, width, and height of the optic foramen were found as 2.40 ± 1.02 mm, 1.83 ± 0.59 mm, and 1.58 ± 0.36 mm, respectively. The measurements of the parameters related to the optic foramen were not statistically different in terms of sides and sexes (P > 0.05). Linear functions for the height, width and surface area of the optic foramen were calculated as: y = 0.711 + 0.040 × weeks, y = -0.019 + 0.086 × weeks, and y = -0.400 + 0.129 × weeks, respectively.

The linear functions in this study can be used to estimate the dimensions of the optic foramen. The calculated regression equations, representing the growth dynamic of the optic foramen showed that the surface area, width, and height were increasing according to gestational ages between 16 and 28 weeks. Microanatomical knowledge related to the optic foramen may be beneficial for surgeons to avoid iatrogenic injury in infants and for anatomists to understand the development of the fetal skull base.