Sarvanga (Sarva=all, whole, entire, complete; anga=limb or body) means the entire body or all the limbs. In this pose the whole body benefits from the exercise, hence the name. (Light on Yoga, p 206)
What is Sarvangasana?
Sarvangasana is a yoga pose that is categorised as an inversion because in this pose the body is upside down and supported by the shoulders. It is an integral pose in all styles and lineages of yoga. In the Iyengar style of yoga we emphasise the importance of correct alignment and balance in the pose, often using props such as bolsters, blankets and belts to achieve the correct alignment.
In many old yoga books you will find this posture also called the Candlestick posture because the body is supposed to resemble a straight candle on a candle holder.