The Ushnisha, or the crown of hair, is the three dimensional oval at the top of the head of the Buddha. Ushnisha is one of the most unique features of Buddhist art and Buddhist iconography. The ushnisha protuberance is not to be mistaken for the topknot Prince Siddhartha cut off upon leaving the city of Lumbini and crossing the river. The topknot is usually only worn by the royal family of the Hindu kingdoms. Once the prince cut it off, it is believed that he renounced his royal heritage.
The original function of the ushnisha was probably intended to symbolize a crown on the top of the head of the Buddha.
The Origins of Ushnisha
While the ushnisha has been ever present and an important feature of many statues and images of the Buddha, it is not clear whether the Buddha actually had an ushnisha on the top of his head or not. There are various textual evidences which clearly state the Buddha having a completely shaved head. In one textual account, for example, a brief account of a hunter who happened to stumble upon the Buddha in the forest. When he saw the former prince sitting in the middle of the forest, the hunter saw a fully bald head of the Buddha and took it as a bad omen and gave up his hunting for the day. Similarly, when he first saw the Buddha, in his monk's robes, the hunter was convinced that the ascetic was a brahmana. However, after a close inspection, he saw this "brahmana" missing the usual shikha, or a tuft of hair on the back of the head, that the brahmanas usually have. These textual evidences, therefore makes it debatable whether the Buddha had an ushnisha or not.
Use of the Ushnisha
The earliest depictions of the ushnisha in the iconography of the Gandhara period were as a crown. The ushnisha on the top of the Buddha's head is the gathering of his wavy and voluminous hair into a chignon. Later, the style and meaning of the ushnisha has undergone various changes. Later, the South Asian depictions of the Buddha have the ushnisha with more schematic appearance. The ushnisha is depicted as an infinitely complex combination of small curls. Though some Buddha Heads have the ushnisha resembling as more of a protuberance coming directly from the skull than a gathering of hair, the evolution of the ushnisha in South East Asian depictions have the chignon replaced completely by either a flame or a lotus flower. Also, the ushnisha is decorated by various metal ornaments in the Buddha heads from this region. One of the main reasons for this change may be, rather than symbolizing the crown of the royal family, the ushnisha is far better interpreted as symbolizing the spiritual power of the Buddha's enlightenment.
Therefore, we can clearly understand that the ushnisha has been a long and evolving presence in various Buddhist artifacts, such as Buddha statues, Buddha heads and other images of Buddha. And the ultimate purpose is necessarily not to depict the physical feature of the historical Buddha, the Shakyamuni, but to depict or represent the special status related to the spiritual power, the knowledge and the religious ideals preached by the Buddha.