Miss. Code Ann. § 63-7-21

Where electric lamps are used to meet the requirements of Section 63-7-11 , they shall be securely and permanently affixed to the permanent structure of the motor vehicle, except for the combination marker lamps on pole-trailers prescribed in subsection (6) of Section 63-7-15 . Required clearance lamps shall be mounted in such a manner as to indicate the extreme width of the motor vehicle and as near the top thereof as practicable. Side-marker lamps may be in combination with clearance lamps and may use the same light source.