an intubating lma construction features a rigid airway tube wherein curvature in a single plane establishes essentially an arcuate path of angular extent in the preferred range of 130 °, plus or minus 5 °, which i have found to be in substantial anatomical conformance with the adult human &# 39 ; s airway path , between a proximal end of the arc at substantial register with the longitudinal midpoint of the hard palate , and a distal end that faces and is at short offset from the glottic aperture , it being understood that my findings apply to suitably quantified allowance for variations in patient - head anatomy , as is for example customary for different sizes of lma devices , each of which is adapted to serve one of five selected patient - size ranges . the proximal end of the rigid tube is suitably a short straight portion which is tangentially and integrally related to the proximal end of the arc . and the distal end of the arc is fitted with flexible mask structure of preferably elastomeric material such as silicone rubber , wherein an internal ramp formation within the mask structure assures a limited but important measure of further and stabilized guidance of an et which has emerged from the distal end of the rigid tube , such that unguided displacement of the et is oriented to target safe entry of the et into the glottic opening .