Surgical anatomy of the turbinal wall of the ethmoidal labyrinth.

The upper part of the lateral nasal wall is formed by a common structure or conchal lamina that is attached all along the junction between the ethmoidal roof and the cribriform plate. From this continuous conchal lamina, the different ethmoidal turbinates take their origin. All these structures form a well defined wall that encloses the ethmoidal cells medially and that deserves the name of "turbinal wall of the ethmoidal labyrinth". The objectives of this paper were: 1) to precisely define the anatomical landmarks of the turbinal wall of the ethmoidal labyrinth, and 2) to study, from an anatomical point of view, the consequences of the surgical resection of the middle turbinate. We performed an anatomic study on 12 frozen human heads, cut in a median-sagittal plane, and then photographed with a millimetre scale in order to perform several measurements. The surface of the turbinal wall of the ethmoidal labyrinth can range from 6.1 to 11.3 cm2. The resection of the middle turbinate preserves approximately half of the turbinal wall, this being around 4.3 cm2 (range 2.6 to 6.3 cm2). The conchal lamina appears as the noble sensorial element of the turbinal wall. It can be described as a continuous bone plate, grossly rectangular in shape, measuring approximately 1 cm in height and 3.5 cm in length that forms the lateral wall of the olfactory groove. The anatomic study shows that its dimensions can vary from simple to double in different individuals. It seems to us that instead of considering the difference of height between the cribriform plate and the ethmoidal roof (Keros classification), we should consider the vertical height of the conchal lamina as a potential risk factor in ethmoidal surgery.