This manipulation is always performed by the operator's wrist, the hands striking qickly. We have four different kinds of Percussion:

(a) Clapping (see Fig. 11), performed with the palms of the hands. It is used to act upon the skin and the superficial nerves and vessels.

(b) Hacking (see Fig. 12) is performed with the ulnar border of the hand. It is used around nerve centers and upon the muscles.

Fig. 13. - Position of Hands in Punctation of the Forehead.

(c) Punctation (see Fig. 13) is performed with the tips of the fingers. It is used upon the head and in circles around the heart.

(d) Beating (see Fig. 14) is performed by the clenched hand. It is used upon the glutei and upon the lower extremities over the sciatic nerve.

Fig. 14.- Beating over the Sciatic Nerve.