diff --git a/src/query/split/split_trimesh.rs b/src/query/split/split_trimesh.rs
index 871af90c..90ad67c4 100644
--- a/src/query/split/split_trimesh.rs
+++ b/src/query/split/split_trimesh.rs
@@ -429,8 +429,13 @@ impl TriMesh {
             }
         };
         let mut add_segment_adjacencies_symmetric = |idx_a: usize, idx_b| {
-            add_segment_adjacencies(idx_a, idx_b);
-            add_segment_adjacencies(idx_b, idx_a);
+            if idx_a < idx_b {
+                add_segment_adjacencies(idx_a, idx_b);
+                add_segment_adjacencies(idx_b, idx_a);
+            } else {
+                add_segment_adjacencies(idx_b, idx_a);
+                add_segment_adjacencies(idx_a, idx_b);
+            }
         };
 
         let mut intersections_found = HashMap::default();