Anatomical Evaluations of The Location and Insertion Shape of Horizontal Rectus Muscle

ABSTRACT

We examined the variations in the limbus-insertion distance, the width and the insertion shape of 260 horizontal recti muscles in 137 strabismic patients, and evaluated the relationship between insertion shape and postoperative results. The average limbus-insertion distance of medial rectus muscle was 4.72 +/- 0.49mm and that of lateral rectus muscle was 6.29 +/- 0.58mm. The width of medial rectus and lateral rectus mascle was 9.84 +/- 0.83mm and 9.57 +/- 0.84mm. The insertion shapes of horizontal rectus muscle were divided into 5 groups, straight, oblique type I and II, concave and convex patterns. According to insertion shape, insertion shape of the medial rectus muscle had no statistic difference in esotropia and exotropia(P=0.179), but in case of the lateral rectus muscle, it was staistically significant in both exotropia and esotropia(P=0.036). When the deviation angle was larger than 40 delta, the length of limbus width was statistically significant in lateral rectus muscle(P=0.018). The insertion shape divided into straight and non-straight pattern was statistically insignificant on postoperative success rate.