“There is a universal reality in ourselves that aligns us with a universal reality that is everywhere else. Alignment from the outermost body or sheath (kośa) to the innermost is the way to bring our own personal Reality into contact with Universal Reality. The Vastasutra Upanishad says, “setting the limbs along proper lines is praised like the knowledge of God.” From the Rig Veda comes, “every form is an image of the original form.” BKS Iyengar, Light on Life, p. 8.
Using the corner of a wall or pillar helps to open the thoracic chest and release the neck (as it should in classic Utthita Trikonasana). The back shoulder should lengthen down the back. The head looks back before looking up. The arms are pushing the wall to arch the chest. In the first photo the edge of wall is between the middle back and base of shoulder blades. In the second photo it is on the bottom base of the shoulder blade. Credit Manouso Manos. All errors are my own.