Beyond the introduction of the spider line it is unnecessary to mention the various steps by which the Gascoigne micrometer assumed the modern forms now in use, or to describe in detail the suggestions of Hooke, 4 Wren, Smeaton, Cassini, Bradley, Maskelyne, Herschel, Arago, Pearson, Bessel, Struve, Dawes, &c., or the successive productions of the great artists Ramsden, Troughton, Fraunhofer, Ertel, Simms, Cooke, Grubb, Clarke and Repsold.
It depends if you're going for a long shot with power or a short shot with power. I'm going to assume you're going for the long shots. Take about 5 steps back at a 7 o clock aâ¦ngle to the ball. Take 3 quick, tiny steps then take a really fast run up.
The angle is to ensure the needle/medicine goes to the proper area, in this case, the fatty layer. A 90 degree angle will most likely land the needle in the muscle, so it is used for an IM shot. A 10 degree angle is used for an intradermal shot, as it will not make it past the skin layers.