The ethmoidal infundibulum is a funnel-shaped/slit-like/curved opening/passage/space/cleft upon the anterosuperior portion of the middle nasal meatus (and thus of the lateral wall of the nasal cavity) at the hiatus semilunaris (which represents the medial extremity of the infundibulum).
The ethmoidal passageway is a narrow, curved channel or slit-like structure located on the front upper part of the middle nasal passage (and thus on the lateral wall of the nasal cavity) at the semilunar hiatus (which marks the medial end of the passageway).