You can see the articulations really well in this inside shot! There are two lames, the top one of which laces onto the gorget, a large piece which has those nice generous wings, and four lames which lap down the outer arm to a highly decorated rerebrace ring. Note especially the high raised ring which goes all around the armour....the bottom part of the rerebrace would fit into that, and the two pieces would turn inside one another. You can see the mechanism better in the pic below.
The spaulders in the picture above still have the top and bottom of the rerebrace ring functional and serviceable. I particularly like the flute down the outside of the arm, and the fancy file work at the middle of each bottom piece. The filework "makes" this style of armour.