elbow joint vs cubitus

elbow joint and cubitus both are nouns.

Word	Noun	Adjective	Verb	Adverb
elbow joint	Yes	No	No	No
cubitus	Yes	No	No	No

As nouns, elbow joint and cubitus are synonyms defined as:

elbow joint and cubitus: hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped

Other synonyms of elbow joint include articulatio cubiti, cubital joint, elbow, human elbow.

elbow joint (noun)	cubitus (noun)
hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped	hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped
	the arm from the elbow to the fingertips