I have a friend of a friend who doesn't have shoulders. Let me try to explain.
A normal person has a torso, a shoulder and then an arm. Whether the person is muscular or skinny, we all have shoulders. They may not be especially round or wide, but they exist. We are all sort of a "T" shape.
This person does not have shoulders. It is almost as if his arms are attached directly to his body. He does not have good posture, but I don't think poor posture could be the sole cause of his extremely sloped shoulders. He is similar to an upside down "V" shape.
What could be the cause of this? Is there a medical condition that he may have? I don't know him well enough to ask him myself, but I'm curious. Has anyone seen/heard of a similar situation?