Critical Elements of the Salamba Shirshasana

Coming into Salamba Shirshasana:

In order to prepare for the asana, make sure you have a folded blanket or padding to support your head and forearms during the pose. Also, if balance is an issue, be sure to set yourself up against a wall in order to focus more on the posture.
When coming into this pose, kneel unto the floor with the mat in front of you. Lace your fingers, placing your forearms onto the mat with your elbows shoulder-width apart. Rolling the arms outward, but with the wrists pressed firmly onto the mat, place the crown of your head unto the mat. Inhale, lifting your shoulder blades and bringing your knees off the floor. Carefully walk your feet closer to your elbows, with your heels elevated. Be sure to actively lift the top thighs, and keep the shoulder blades firm, lifting them towards the tailbone so you're not compressing your neck.
Once you feel you are ready, exhale, bending your knees and lifting them off the floor. Before straightening out your knees, be sure to align your thighs in line with the torso, and underneath the pelvis. Then, when ready, straighten out your legs. Hold this position for about a minute, to begin with.

Coming out of Salamba Shirshasana:

When leaving this pose, slowly exhale, without losing the lift of the shoulder blades, and have both feet touch the floor at the same time. Do not come down heavily as it will put stress on the neck. When in this position, you can start to exit this pose, and rest in Child's Pose for a few moments.

Actions and muscles involved in this Salamba Shirshasana:

Salamba Shirshasana takes a lot of core strength in order to rise to full posture. In this pose, one must be steady with their balance, and not to rush coming into or out of this pose, for it would put stress on the neck. This pose requires a lot of strength in the neck and shoulders, as well as the core and the upper spine. This pose also incorporates asanas like Tadasana, mountain pose, Adho Mukha Svanasana, Downward-Facing Dog, and Urdhva Dandasana, Upward Staff Pose.