In Iyengar Yoga, most props are used diversely, with a purpose to emphasize a certain action or effect. However, a platform for Sarvāṅgāsana is used consistently. Many students wonder about this, especially if they have practiced Sarvāṅgāsana without props in other yoga methods. Using the platform has a basic anatomical explanation: the human anatomy does not allow the head to bend forward to form a 90° angle between the thoracic and the cervical spine. The following photo shows bending the head forward from an upright sitting position. If you insist on bending the head until the back of the skull is parallel to the floor, you will necessarily have to curve the upper back: This means that in Sarvāṅgāsana you will not be able to raise the thoracic spine and open the chest, and you will experience a heavy load on the neck which may lead to injury. The platform is a simple and useful way to do an effective and safe Sarvāṅgāsana. ^ Back to top