Suman Chiplunkar's this book will give you detail idea about Mudras.The art of forming mudras or hand gestures is an ancient one. Developed and practised by rishis and hermits of yore, mudras and mantras (syllabic sounds) were thought to be potent and healing forces. Faced with today's demonic stresses and the life-threatening illnesses they spawn, some people are exploring traditional solutions, including hatha yoga, pranayama, meditation, past life regression, mantra and tantra, and mudras.
According to Suman K.Chiplunkar, author of Mudras and Health Perspectives, the nerves in the human body carry electromagnetic powers. “These are emitted through the tips of our fingers, nose tip, toes, etc. Our ancient yogis evidenced that creation comprised Panchamaha (five fundamental) mudras . And the entire universe is made up of five elements (Pancha bhoota). These five elements had to be balanced for a healthy life in an individual. It was logically concluded, then, that the five fingers on the human hand were manifestations of five outer elements in nature. For instance, the thumb denotes agni (fire), the index finger vayu (air), middle finger stands for space (aakasha), the ring finger depicts earth (prithvi) and the little finger water (jala).”