The Mexican statue is of a Yin developed human body.
The way the arm and shoulder look together,
and the way the shoulder and chest look together,
are both characteristic of Yin body development.
If you are having trouble figuring out what it is you should notice, the large distance between the shoulder and chest should have caught your attention,
and the large gap found under the shoulder that is a product of this particular relationship between the arm and the shoulder should have caught your attention.
The gap that is highlighted is not a side effect of the hands being tied behind the back, although that condition does perhaps make the gap slightly larger. Even if the hands were unbound and hanging free, there would be a noticeable space with a particular look that would be found in front the armpit, below the shoulder, and behind the chest.
The large size of the head,
and the depth of the face,
are also characteristic of Yin developed human bodies.