We come across people striking one’s own head with knuckles
while prayer to Ganesha in temples and other sacred places. The story and
reason of worshipping Ganesha by striking head with joints of fingers when the
fist is closed is associated with the origin of the Kaveri River .
Legend has it that Sage Agastya was carrying Holy Ganga
River water given to him
by Shiva in a Kamandalu. He reached the southern part of India which was
under a severe drought.
He paused to take rest. He placed his Kamandalu beside him
and soon fell asleep.
Ganesha in the form of a crow arrived there and knocked the
Kamandalu down. The water inside the pitcher started flowing through the
drought-stricken land and it became the Kaveri River .
The sage on waking up tried to chase the bird away which
then transformed into a small boy. Sage Agastya ran after him intending to
strike him on his head with his fist.
After running for awhile, the body assumed his divine form.
Sage Agastya was full of remorse and began to strike his own
head with his knuckles.
Ganesha stopped him and declared that henceforth all those
who worshipped him in this manner would be graced with wisdom.