The curvature of the nasal septum (NS) is one of the most widespread deformations of the facial skeleton. The objective of the present study was to substantiate the principles of and develop the rationale for the surgical correction and conservative treatment of this condition based on the morphological features of various types of deflection of the nasal septum. We have undertaken the morphological analysis of the osseous and cartilaginous structures determining the type and the shape of the curvature of the nasal septum together with the clinical analysis of different morphological variants of the deflection of the nasal septum making use of the R. Mladina classification. Type I—IV vertical deflections are regarded as the acquired deformities whereas type II deviations can just as well be congenital malformations. Types V and VI deflections can be a consequence of the birth injury resulting in the displacement of the nasal structures and leading to the curvature of the nasal septum. The authors describe the defects in the anatomical structures adjoining the nasal cavity associated with various types of the deflection of the nasal septum that the surgeons should take into account when planning and performing septoplasty.