cubitus vs cubital joint

cubitus and cubital joint both are nouns.

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

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

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

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

cubitus (noun)	cubital joint (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