Try putting down where the scapula and humerus are. You know the ulna connects with the humerus and you know the radius connects with the wrist. Also, the forearms are pronated so you know the radius has rotated to cross the ulna. You can see the Afro ion and the epicondyles so crack open an anatomy book with a similar pose or you could use the Skelly app and reproduce the pose to understand it. That’s how I would attack the problem, anyways

Sundjiv. I would say that the lines that you see in your top two circles are both indicating the division between the infraspinatus mm and the teres major muscle. Your bottom left circle is primarily in the area of the latissimus dorsi (lats) as it wraps from the back moving up towards its insertion on the upper/inner arm. Hopefully that helps.

Hi @Sundjiv, Nice studies! I think you're really close with the ribcage! I attached a tracing of how I think I would've have done it I hope this helps :)