According to the legend, after the battle of Kurukshetra, the Pandavas went to sought the blessings of Lord Shiva to atone their sins. But Lord Shiva, who din't want to meet them finally eluded. When the Pandavas came to know where Lord Shiva is, the Lord took the form of a bull to hide himself.
The Pandavas were not ready to accept it. One of the Pandava, Bhima tried his best to pick up the bull (Lord Shiva) but failed and the bull sacattered into pieces. The pieces sank into the earth but however Bhima managed to retain the hump of the bull (Lord Shiva)
Impressed by the determination of Pandavas, Lord Shiva finally blessed them and freed them from their sins. The lord then asked them to worship his hump at Kedarnath. This conical protrusion is worshipped as the idol in the shrine.
The other parts of bull's (Lord Shiva's) body went as Arms (Bahu) at Tungnath, Face (mukh) at Rudranath, Navel (nabhi) at Madmaheshwar and Hair (jata) at Kalpeshwar.
These four shrines along with Kedarnath are worshipped as Panch Kedar. They are as follows: