diff --git a/skimage/restoration/tests/test_unwrap.py b/skimage/restoration/tests/test_unwrap.py
index fca63724..764e8b74 100644
--- a/skimage/restoration/tests/test_unwrap.py
+++ b/skimage/restoration/tests/test_unwrap.py
@@ -144,5 +144,12 @@ def test_invalid_input():
     assert_raises(ValueError, unwrap_phase, np.zeros((1, 1)), 'False')
 
 
+def test_unwrap_3d_middle_wrap_around():
+    # Segmentation fault in 3D unwrap phase with middle dimension connected
+    # GitHub issue #1171
+    image = np.zeros((20, 30, 40), dtype=np.float32)
+    unwrap = unwrap_phase(image, wrap_around=[False, True, False])
+    assert np.all(unwrap == 0)
+
 if __name__ == "__main__":
     run_module_suite()
diff --git a/skimage/restoration/unwrap_3d_ljmu.c b/skimage/restoration/unwrap_3d_ljmu.c
index 88012f18..ebbf02ce 100644
--- a/skimage/restoration/unwrap_3d_ljmu.c
+++ b/skimage/restoration/unwrap_3d_ljmu.c
@@ -786,7 +786,7 @@ void  verticalEDGEs(VOXELM *voxel, EDGE *edge, int volume_width, int volume_heig
 		}
 	      voxel_pointer++;
 	    }
-	  voxel_pointer += next_voxel + 1;
+	  voxel_pointer += next_voxel;
 	}
     }
   params->no_of_edges = no_of_edges;