Radiography (fig. 1) reveals that the sculpture is fashioned over a central armature whose construction closely resembles the small sketch noted in figure 2. Identified using XRF as lead,  the central armature consists of intersecting hollow pipes approximately 0.5 inch in diameter. It is of interest to note that Degas incorporated somewhat standard armature materials and configuration to make this masterpiece, choosing “lead pipes ½ ″ and 1″ diameter,” an item listed among those Auguste Rodin’s student Malvina Hoffman prescribed as necessary in a sculptor’s studio for fabricating armatures.
One pipe provides a vertical central support that attaches to an inverted U-shaped pipe at the groin, each side of the U extending downward into a leg. Inside the legs, most notably in the right, the pipes were bent to accommodate the pose of the dancer. As observed in the radiograph of the left foot, the pipe was secured by screws into an oblong metal plate on the base. That of the right leg was wrapped using wire to provide texture to the surface so that a clay core could be built up over it. A small sample of the core from the top of the right leg, examined using PLM and SEM, was identified as a water-based air-dried clay (ferruginous aluminosilicate clay), henceforth in this entry referred to as clay.
The complex construction of the figure, emanating from the vertical rod in the body, is repeated at slight variances in the limbs, neck, and head. It can be loosely characterized as often containing an internal organic bulking element bound to an armature, over which clay and ultimately wax are added. In the torso, this internal mass appears to have been roughed out in two stages. The innermost portion consists primarily of pieces of wood held to the central armature with tightly twisted wire.  Over this a second layer of organic matter (similar in density to cotton batting) is bound with rope from the groin to just above the waist (fig. 2). A visual aid useful for interpreting the rope-bound core of the torso can be seen in the comparison of the rope core of the fingers and their radiograph (fig. 3).