The proximal end of the human femur represents the result of a long, phylo- and ontogenetic evolutionary process. Its functional structure is determined by biomechamical stresses imposed by the necessities of locomotion and of the upright position, the principal role being that of gravitational pull and the resultant contraction of the two major muscular groups. The older classifications of the fractures of the trochanteral massif, based on anatomical description, is being replaced by the classification based on pathophysiological data, with therapeutic and prognostic value. The notion of instability sets the course in the field of therapeutical principles, of which the most important is, certainly, the refection of the major sustentation pillar--the internal or the calear-femural cortical.