Proposition.

--------------------------------------------------
Note added at 51 mins (2015-09-19 13:29:41 GMT)
--------------------------------------------------

It is doubtful that percussingtapping is involved, but this is what opukać may mean - non-tender to percussion

--------------------------------------------------
Note added at 1 hr (2015-09-19 13:42:23 GMT)
--------------------------------------------------

Anterior chest wall was nontender to palpation, equal expansion bilaterally.
https://sites.google.com/site/medicaltranscriptionsamples/ph...
cccccccccccccccccccccc

Frontal and maxillary sinuses are nontender to palpation and percussion
http://ww3.bergen.edu/faculty/wguariglia/charting_examples.h...
ccccccccccccccccccccc

Her temporal arteries are elastic and nontender to palpation.
https://books.google.com/books?id=XuGdAgAAQBAJ&pg=PA289&lpg=...
ccccccccccccccccccccccc
Patientis supine, with left leg abducted and externally rotated. HEENT: Head and neck nontender to palpation
https://books.google.com/books?id=hiBO3dLO5JkC&pg=PA358&lpg=...
cccccccccccccccccccc

he abdomen should be soft and nontender to palpation.
https://books.google.com/books?id=qdmBXAtC3lMC&pg=PA280&lpg=...
ccccccccccccccccccccccc

; salivary glands nontender; temporal artery pulsations visible bilaterally, soft and nontender to palpation;
https://books.google.com/books?id=Z8XsAwAAQBAJ&pg=PA197&lpg=...
ccccccccccccccccccccccccccccccccccccccccccccccccccccc
The abdomen is nontender to percussion and palpation
https://books.google.com/books?id=rfcADZRir-wC&pg=PA255&lpg=...
ccccccccccccccccccc

An examination of the sinuses showed that they transmitted light and were nontender to percussion
http://www.va.gov/vetapp00/files1/0000084.txt

NOT TENDER WHEN PULPATED

Osobno. Zwroty pisane razem są rzadkie.
Links will be added.
[...]
the course of the vein, which may be tender to palpation if secondary venous ...

[....]
etermine if the vessel was not palpable on the basis of limited blood ..

https://meded.ucsd.edu/clinicalmed/extremities.htm
[...]
Examination of the cardiovascular system includes palpation of the cardiac apex.
http://patient.info/doctor/aortic-stenosis-pro

NOT palpable / on / upon - RÓŻNICOWANIE PÓŹN IEJ.

A to jeszcze nie koniec.
Cdn.


--------------------------------------------------
Note added at   19 godz. (2015-09-20 07:51:00 GMT)
--------------------------------------------------

Percussion is a method of TAPPING on a surface to determine the underlying structure, and is used in clinical examinations to assess the condition of the thorax or abdomen. (THORAX AND ABDOMEN). It is one of the five methods of clinical examination, together with inspection, palpation, auscultation, and inquiry
https://en.wikipedia.org/wiki/Percussion_(medicine)

Palpation is the process of using one's hands to examine the body, especially while perceiving/diagnosing a disease or illness.[1] Usually performed by a healthcare practitioner, it is also the process of feeling an object in or on the body to determine its size, shape, firmness, or location (such as a veterinarian would check/feel the stomach of a pregnant animal to ensure good health and successful delivery).
https://en.wikipedia.org/wiki/Palpation

EXAMPLES: GENERAL LINK (sources/studies/ case reports/ literature)
https://www.google.pl/#q=to palpate the veins (just as an example)
TO PALPATE THE VEINS ETC- RESULTS:
https://www.google.pl/#q=to palpate the veins
DEFINITIONS:
Percuss: / PERCUSSION
1. in physical examination, striking a part of the body with short, sharp blows of the fingers in order to determine the size,position, and density of the underlying parts by the sound obtained. Percussion is most commonly used on the chest andback for examination of the heart and lungs. For example, since the heart is not resonant and the adjacent lungs are, whenthe examiner's fingers strike the chest over the heart the sound waves will change in pitch. This serves as a guide to theprecise location and size of the heart.
2. the rhythmic clapping of cupped hands over various segments of the lungs to mobilize secretions; called also cupping.
THE SECOND ONE:
1. A diagnostic procedure designed to determine the density of a body part by the sound produced by tapping thesurface with the finger or a plessor; performed primarily over the chest to determine presence of normal air content in thelungs and over the abdomen to evaluate air in the loops of intestine and the size of solid organs such as the liver andspleen.
2. A form of massage, consisting of repeated blows or taps of varying force.

THE THIRD ONE:
A method of medical diagnosis in which various areas of the body, especially the chest, back, and abdomen, are tappedwith the finger or a plexor to determine by resonance the condition of internal organs.
http://medical-dictionary.thefreedictionary.com/percussion

PALPATION- DEFINITION:
The act of feeling with the hand; the application of the fingers with light pressure to the surface of the body for the purpose ofdetermining the condition of the parts beneath in physical diagnosis.

1. Examination with the hands, feeling for organs, masses, or infiltration of a part of the body, feeling the heart or pulsebeat, or vibrations in the chest.
2. Touching, feeling, or perceiving by the sense of touch.
a technique used in physical examination in which the examiner feels the texture, size, consistency, and location of certainbody parts with the hands. palpate, v.
Clinical medicine
1. A part of a physical examination, in which an examiner lighly presses with the hands over the surface to ID lumps,bumps, beating, buzzing, and burbling of the body below. See Percussion. Cf Palpitation.
2. Touching, feeling. Cf Touchy-feely.
1. Examination with the hands, feeling for organs, masses, or infiltration of a part of the body, feeling the heart or pulsebeat, vibrations in the chest, and other diagnostic functions.
Synonym(s): touch (2) .
2. Touching, feeling, or perceiving by the sense of touch.

http://medical-dictionary.thefreedictionary.com/palpation

DISCUSSION:
I completely and basically agree with Frank that the term used in this particular context and- first of all- in this sentence (that makes sense when analyzed step by step and comprehensively)- so taht the term- 'percussion' might be or even is quite ambiguous.
First of all (IMHO) one should try to determine which parts of the body can be subject of palpation/ percussion and the second thing is- for which purposes this medical procedure is used. In my opinion; associating the word 'palpation' with abdomen (abdominal examination consisting of: observation, auscultation, percussion, and palpation.) is not necessarily the right direction and- for certain- not the only one option that should be considered while answering a question regarding veins/ 'venous vessels' etc.
Basic words are: TAPPING/ PALPATION/ or even TOUCH -ING (the essence of a medical translation is to avoid any errors/mistakes and these can in fact be avoided when/if one gives a general term (when not being sure what is meant in DETAILS).
FINAL CONCLUSION:
Yes- there is a difference- a basic one between palpation/ percussion etc. One thing is certain- 'palpation' is here rather (still rather) not the case. One thing is – on the other hand- uncertain. Is percussion in such a specific context the right word? I personally doubt it. It might be right, but the analysis of diverse and diversified sources rather does not ‘provide’ a “confirming answer”. This is it.
Last but not the least:
I am really curious how the entire sentence could be translated. I do not know that. What I do know is that not words but phrases in accordance with a particular context are the starting point for any (critical)“considerations’.