In an endoscope system, a nasal endoscope (211) for entry in a first external nostril of a patient includes a first elongated tube with a first distal portion (20), an imaging window (55), a lighting window (56), and an instrument channel.An assist device (212) for entry in a second nostril includes a second elongated tube with a second distal portion (37), and a second lighting window (292). A retaining device (23, 24) removably retains the second distal portion on the first distal portion, to cause a peripheral part of said second distal end surface to contact on a peripheral part of said first distal end surface positioned opposite to said first lighting window with reference to said distal opening. This allows more even illumination, and avoids shadows.
