LG Monitor Installation Manual page 20

Causes & Phenomena of the Line Defect
The line defect would occur on your Set if you strike on the edge of the Set.
LOG (LINE ON GLASS) DEFECT
Shock on Module Left/Top Corner Left/Top LOG Crack Horizontal Line Defect
LOG (LINE ON GLASS) DEFECT
Shock on Module Top Side  Top COF Crack
Vertical Line Defect
Shock on Module Left Side  Left COF Crack
Horizontal Line Defect