Morphometric Study of Relationship between Plane of Inferior Oblique Muscle and Adjacent Globe Structure

ABSTRACT

There are no known data of recession point of inferior oblique muscle (IO) in Korean.The purpose of this study was to determine the accurate reinsertion point of IO and compare the previous data with ours.Thirty-one Korean cadaver orbits were dissected to expose the full length of extraocular muscles and sclera, and then we measured the length from the recession point of IO to lateral edge of insertion of inferior rectus muscle (IR)and to inferior edge of insertion of lateral rectus muscle (LR).Eight mm recession point of IO was measured 6.9 +/-0.6 mm posteriorly along the inferior border of LR from inferior edge of LR insertion, and 4.6 +/-1.5 mm inferiorly.For 10 mm recession, it was 5.6 +/-1.3 mm posteriorly and 6.6 +/-2.0 mm inferiorly.For 12 mm recession, it was measured 4.7 +/-0.7 mm posteriorly and 8.4 +/- 1.5 mm inferiorly.And for 14 mm recession, it was 3.7 +/-1.7 mm posteriorly and 9.5 +/-2.0 mm inferiorly. Eight mm recession point of IO was measured 3.5 +/-0.6 mm posteriorly along the lateral border of IR from the lateral edge of IR insertion, and 6.5 +/-0 .8 mm laterally.For 10 mm recession, it was 2.9 +/-1.0 mm posteriorly and 3.6 +/- 1.0 mm laterally.For 12 mm recession, it was measured 3.3 +/-0.6 mm posteriorly and 2.3 +/-0.6 mm laterally.For 14 mm recession, it was 3.0 +/-1.5 mm posteriorly and 0.5 +/-0.9 mm laterally.The cord length on a straight line from 14 mm recession point of IO to the scleral exit site of the inferior temporal vortex vein was 6.6 +/-1.4 mm (range 4~9 mm).The distance from IO recession points to IR insertion site and to LR insertion site were compared in ten paired eyes, and the difference was not statistically significant (p>0.05).We made anatomical studies to evaluate the proper placement of scleral reinsertion site of IO in Korean.