Ocular rectus muscle insertions revisited: an unusual anatomic approach

Twenty-five normal adult eyes, taken from fresh human cadavers, were specially prepared in view of the measurements of the arc length of different segments of the globe. The distances measured between the anterior limbus and the scleral insertions of the rectus muscles were similar to those in previous studies with respect to the 'spirale de Tillaux' and a high interindividual variability, i.e. medial rectus 6.2 +/- 0.6 mm, inferior rectus 7.0 +/- 0.6 mm, lateral rectus 7.7 +/- 0.7 mm, superior rectus 8.5 +/- 0.7 mm. The distance between each pair of opposite rectus muscle insertions shows a high interindividual variability (horizontal axis 25.45 +/- 1.38 mm, vertical axis 25.55 +/- 1.45 mm), but the ratio between both distances was always equal to 1 (0.997 +/- 0.031) with a statistically significant correlation (2-tailed p = 0.96). This new approach to rectus muscle insertions may be important for a better understanding of some possible anatomically related factors in strabismus.