Touching something you can see is a frequently used test of fine motor control. Child care workers ask children to touch an object they are holding, doctors ask you to touch your index finger tips together at eye level to test for nerve damage and police ask you to touch your index finger to the tip of your nose to test for inebriation. Pinching, including picking up small objects with your fingers and thumb, is a fine motor skill that is a normal part of a child's development. These fine motor skills are called primary because they appear early and we use them to construct other fine motor skills. For example, typing is a skill that can only be developed if the ability to intentionally touch a target object is well under control.
Many fine motor skills involve manipulation of a stylus, a rod like object that ends in some sort of tool. We start learning this skill with crayons and graduate to pencils and pens. Painters learn to manipulate brushes with amazing skill, as sculptors do with various chisels and scrapers. Stylus manipulation not only involves manipulation, it involves "hepatic feedback." We are so used to manipulating a stylus that we can "feel" the texture of a surface by running a stylus over it. Dentistry is only one of the professions that rely on a highly developed ability with the fine motor skill of manipulating a stylus.
Some positional skills are learned without conscious effort--like turning you palm up when you reach behind you or shaping your hand to grip an object for which you are reaching. Some positioning skills, like typing and playing the guitar, are only learned with considerable effort. Positioning skills often involve eye-hand coordination, utilizing both the small muscles of the fingers and the small muscles of the eyes. Most positioning involves the thumb and the two big fingers next to the thumb. The small finger is just too short and weak and the finger next to the small finger (musicians call it "the stupid finger") does not seem to be wired up as well or as independently as the other fingers.