ulnar nerve vs nervus

ulnar nerve and nervus both are nouns.

Word	Noun	Adjective	Verb	Adverb
ulnar nerve	Yes	No	No	No
nervus	Yes	No	No	No

As nouns, nervus is a hypernym of ulnar nerve; that is, nervus is a word with a broader meaning than ulnar nerve:

ulnar nerve: a nerve running along the inner side of the arm and passing near the elbow; supplies intrinsic muscles of the hand and the skin of the medial side of the hand
nervus: any bundle of nerve fibers running to various organs and tissues of the body

Other hypernyms of ulnar nerve include nerve.

ulnar nerve (noun)	nervus (noun)
a nerve running along the inner side of the arm and passing near the elbow; supplies intrinsic muscles of the hand and the skin of the medial side of the hand	any bundle of nerve fibers running to various organs and tissues of the body