A nerve is made up of bundles of smaller nerves these individual nerve cells can be either efferent or afferent - they don't do both. So a nerve that takes sensory from the skin ( afferent) can not motor component at the skin. In the spinal nerve (the bundle of a bunch of nerve axons) there are many nerve cell axons that end up at a muscle (efferent) - they split off before it gets to the skin. A spinal nerve is really only a couple of cm's long before it splits into a rami which further split into anterior/posterior/muscle nerves/etc. There are no muscles in the skin (except for the muscle that gives you goose bumps - which is under sympathetic control not motor).
Merged post follows:
Consecutive posts mergedA nerve is made up of bundles of smaller nerves these individual nerve cells can be either efferent or afferent - they don't do both. so a nerve that takes sensory from the skin ( afferent) does not have to have any motor component at the skin, even though in the spinal nerve (the bundle of a bunch of nerve axons) there are many nerves cell axons that end up at a muscle (efferent) - they split off before it gets to the skin. A spinal nerve is really only a couple of cm's long before it splits into a rami which further split into anterior/posterior/muscle nerves/etc. There are no muscles in the skin (except for the muscle that gives you goose bumps - which is under sympathetic control not motor).
