Body element of a motor vehicle

The invention relates to a body panel element of a motor vehicle comprising two main walls (21; 22) extending in a transverse direction (Y) of the vehicle and forming between them an angle comprised between 60 and 120°, in particular an angle substantially perpendicular, considered according to a view parallel to this direction, characterized in that it comprises at least one configuration (7) arranged as a buttress between the two main walls (21; 22) and provided with a secondary wall (23) in slope forming with each of the main walls (21; 22) an angle comprised between 5° and 60°, this secondary wall (23) receiving a cable grommet (8) allowing a cable (9) to pass through the secondary wall (23).