An estimation method for estimating the bone mineral density distribution in at least one portion of a person's skeleton, the skeleton being made up of bone tissue, the bone tissue being surrounded by soft tissue, in turn surrounded by an outline of the person, the method being characterized in that it comprises generating: - a geometrical representation in three dimensions of said portion of the person's skeleton; - a geometrical representation in three dimensions of at least one portion of the outline containing said portion of the person's skeleton; - at least one first X-ray image of said at least one portion of the skeleton, this first image being generated by observing a projection onto a first detection surface of X-rays, coming from a first source, the first image being generated by projecting X-rays and representing the person as observed from a first observation angle of incidence; and - at least one second X-ray image of said at least one portion of the skeleton, the second image being generated by projecting X-rays and representing the person as observed from a second observation angle of incidence distinct from the first observation angle of incidence; and then using predetermined software and for a plurality of given X-rays selected from among said projected X-rays, estimating for each given X-ray: - a value for the thickness of soft tissue through which the given X-ray has passed; - a value for the thickness of bone tissue through which the given X-ray has passed; and - a value for the overall attenuation of the given X-ray between its source and its projection onto the detection surface onto which it is projected; and - using the thickness value for soft tissue through which the given X-ray passes, and using an estimate for an attenuation coefficient of the soft tissues through which the given X-ray passes, deducing firstly a value for the attenuation of the given X-ray due to the thickness of soft tissue through it has passed and secondly a value for the attenuation of the given X-ray due to the thickness of bone tissue through which it has passed; and then - using the value for the thickness of bone tissue through which the given X-ray has passed, the value for the attenuation of the given X-ray due to the thickness of bone tissue through which it has passed, and the overall value for attenuation of the given X-ray, the software estimates a value representative of the bone mineral density of the bone tissue through which the given X-ray has passed. - a geometrical representation in three dimensions of said portion of the person's skeleton; - a geometrical representation in three dimensions of at least one portion of the outline containing said portion of the person's skeleton; - at least one first X-ray image of said at least one portion of the skeleton, this first image being generated by observing a projection onto a first detection surface of X-rays, coming from a first source, the first image being generated by projecting X-rays and representing the person as observed from a first observation angle of incidence; and - at least one second X-ray image of said at least one portion of the skeleton, the second image being generated by projecting X-rays and representing the person as observed from a second observation angle of incidence distinct from the first observation angle of incidence; and then - a value for the thickness of soft tissue through which the given X-ray has passed; - a value for the thickness of bone tissue through which the given X-ray has passed; and - a value for the overall attenuation of the given X-ray between its source and its projection onto the detection surface onto which it is projected; and - using the thickness value for soft tissue through which the given X-ray passes, and using an estimate for an attenuation coefficient of the soft tissues through which the given X-ray passes, deducing firstly a value for the attenuation of the given X-ray due to the thickness of soft tissue through it has passed and secondly a value for the attenuation of the given X-ray due to the thickness of bone tissue through which it has passed; and then - using the value for the thickness of bone tissue through which the given X-ray has passed, the value for the attenuation of the given X-ray due to the thickness of bone tissue through which it has passed, and the overall value for attenuation of the given X-ray, the software estimates a value representative of the bone mineral density of the bone tissue through which the given X-ray has passed. - using the thickness value for soft tissue through which the given X-ray passes, and using an estimate for an attenuation coefficient of the soft tissues through which the given X-ray passes, deducing firstly a value for the attenuation of the given X-ray due to the thickness of soft tissue through it has passed and secondly a value for the attenuation of the given X-ray due to the thickness of bone tissue through which it has passed; and then - using the value for the thickness of bone tissue through which the given X-ray has passed, the value for the attenuation of the given X-ray due to the thickness of bone tissue through which it has passed, and the overall value for attenuation of the given X-ray, the software estimates a value representative of the bone mineral density of the bone tissue through which the given X-ray has passed.