Natural Shoulder: clarify please!

[Guest]

My problem is one of both terminology and anatomy.
I become lost when people talk of a shoulder seam falling on the natural shoulder as my understanding of this joint is of a complex form curved in three dimensions; I cannot pick one point as the end of the shoulder. Does this term refer to the seam falling on the end of the clavicle (I assume not), vertically above the acromion process (the protusion of the scapula which one feels through the deltoid if pushed just below the end of the clavicle), or should the seam be situated simply where the line of the hanging arm would meet the line of the shoulder slope if both were extended? This last would mean there would still be a portion of 'overhang' or empty space within the coat.
On a coat with a natural shoulder, when the arm hangs relaxed, should the angle of the sleeve project from the body with it or hang close to vertical?
Deepest apologies for the tortuous writing, and the nomenclature, but this is very hard to explain. Hope you can help, thanks.