Other times props are used to bring awareness to poses. Sure, I can get my hand down to the floor in Utthita Trikonasana, but what am I giving up to bring my hand down to the floor? What changes in the pose when I put my hand on a block? In this example, the prop is being used to bring awareness to a certain aspect of the pose.
A third way to use props is to create work where a body part was being a little lazy. In other words, making poses harder. That is what we will explore today in Adho Mukha Svanasana.
Working on the other end now, place a strap directly around your elbows. If you have tight shoulders and have trouble straightening your arms, pull your arms inward, away from the strap - make the strap looser. If you have open shoulders and have trouble engaging your arms completely, press out into the strap - make the strap tighter.
Then move the strap up the arms, about midpoint on the upper arm. You can press your head into the strap to open up your shoulders, or you can use it to get your head closer to the floor. This is very similar to the arms behind the head, which is the last human picture from this post.
Of course, if you can reach the floor easily, raise the height of the floor.