Mahanyasapurvaka Rudrabhishekam :
Nyasa is releated to the assignment of various parts of the body of Lord Shiva (from head to foot). Maha Nyasam means incarning Lord Shiva into our body. By performing Abhishekam with sacred waters after Mahanyasa is said to be Mahanyasa Poorvaka. Sri Rudram is the vedic hymn which glorifies Lord Shiva which purifies the entire atmosphere and wipes out distress in humanity.