part of outer trumpet wall pinna Fig 75,76 Abbr: Pi in ISBN:0-937548-00-6. TGMA:0000990 TGMA:0000990 The part of the trumpet from the apex to an imaginary line drawn more or less perpendicular to the longitudinal axis at the most proximal margin of the spiracular opening, the part distal to the meatus; extent expressed as a fraction of the trumpet length. default_namespace