Blow out fracture of the orbit, most commonly leads to fracture of -
"The most common site for a blowout fracture to occur is the posteromedial aspect of the orbital floor, medial to the infraorbital neurovascular bundle where the maxillary bone is very thin." - The Internet Journal of Otorhinolaryngology.
Posteromedial floor of orbit
Medial wall of orbit
Lateral wall of orbit
Roof of orbit