Nervus and Sciatic nerve

Nervus noun - Any bundle of nerve fibers running to various organs and tissues of the body.

Sciatic nerve and nervus are semantically related. In some cases you can replace phrase "Sciatic nerve" with "Nervus", this terms are similar.

Sciatic nerve noun - Arises from the sacral plexus and passes about halfway down the thigh where it divides into the common peroneal and tibial nerves.

Nervus and sciatic nerve are semantically related. You can use "Nervus" instead a noun phrase "Sciatic nerve".