... rather than lymphatic vessels; this was my first idea when reading the question.
see this German ref. text:
http://www.radiologiebadaibling.de/i_aerzte.html (find -> Körperstammgefäße, i.e., Aorta thoracalis, Aorta abdominalis, renal arteries).
IF lymphatic vessels are meant, then "trunk vessels" is the correct expression, however, if arteries are meant, then we should use EN -> "major blood vessels" (... of the trunk) - or similar. Then also "trunk blood vessels" is possible - to differentiate from lymphatic vessels.
cf "major vessels":
http://faculty.orangecoastcollege.edu/happ/presentations/BIO... (slide 52 of 99)