**Figure 1:** a) The prototype of the Macintosh laryngoscope. b) The
current English Macintosh laryngoscope (size 3). Reference lines
and points: line LN, a horizontal line drawn from the handlemounting
block; point T, the blade tip; line TN, a line drawn from
the point T perpendicular to the line LN; point M, a point of
intersection of the line LN and under surface of the midportion and
point F, a point of intersection of the line TN and extended line of
the midportion. The line BN is the length of the laryngoscope. c)
The overlaying image of the original design of the Macintosh
laryngoscope on the radiograph laryngoscopy image. The black
eyeline: with the current Macintosh laryngoscope; the white eyeline:
with the prototype of the Macintosh laryngoscope. |