Another possible diagnosis included pulmonary embolus.

which words are verbs?
pulmonary embolus = verb

The external oblique fascia was then incised, and the incision was lengthened in the direction of the fibers using Metzenbaum scissors.

was incised = verb
was lengthlened = verb

first sentence -- incorrect guess about the verb

second sentence -- both verbs are correct (Did you guess? Or are you choosing after thinking?)

http://www.chompchomp.com/terms/verb.htm

Well, trying to remember which is which. Long time since I have done any Grammar and I am pretty exhausted right now haha.

Read in book that says Other verbs indicated a condition.
diagnosis = verb

Verbs fall into two main categories:

Action verbs -- things you can DO
~~walk, talk, think, consider, believe, use, include, exclude ...
http://grammar.ccc.commnet.edu/grammar/verbs.htm

Linking verbs -- forms of "to be" (am, are, is, was, were ... ) and a few others:
http://grammar.ccc.commnet.edu/grammar/verbs.htm#linking

In the sentence "Another possible diagnosis included pulmonary embolus," there are no verbs. "Pulmonary embolus" is a noun phrase, not a verb.

In the sentence "The external oblique fascia was then incised, and the incision was lengthened in the direction of the fibers using Metzenbaum scissors," the verbs are "was incised" and "was lengthened." These verbs indicate the action of cutting the external oblique fascia and extending the incision.