The role of orbital wall morphological properties and their supporting structures in the etiology of "blow-out" fractures.

The stiffness and strength of the orbital walls are proportionally dependent on the anatomical structures which support and strengthen these walls from the opposite side. The medial wall is therefore strong due to the support of ethmoid cells. The floor is stronger the less surface there is and the more supported it is by trabeculae of the maxillar sinus. The strength of the upper and lateral walls are proportional to their thickness. The orbital floor is on the average the weakest, followed by the medial and upper walls. The lateral wall is the stiffest and the most rigid. Computed tomography (CT) has improved structural analysis of the orbital contents and orbital walls enabling the visualisation of superficial and deep soft tissues and bone structures.