[165] Sliding calipers: Separate measurement of each half of the
body, from the lowest point on the posterior border of each ramus not
affected by the angle to a point of corresponding height on the line
of the symphysis. The anterior point may, in consequence of a lower
or higher location of the posterior point, range from the chin to
above the middle of the symphysis, but the results are much alike. The
measurement leaves much to be desired, but is the best possible if the
two halves of the body are to be measured separately.
[166] The length of the whole jaw is measured on Broca's mandibular
goniometer, by laying the jaw firmly on the board, applying the movable
plane to both rami, and recording the distance of the most anterior
point of the chin from the base of the oblique plane. This measurement
is easier than the previous, though on account of the variation in the
angles and the lower part of the posterior border of the rami it is
also not fully satisfactory, and it does not show the differences in
the two halves of the body.
[167] Sliding calipers: One branch applied so that it touches the
highest points on both the condyle and the coronoid, while the other
is applied to the lowest point of the ramus anterior to the angle, if
the bone here is prominent; if receding, the branch of the compass is
applied to the midpoint on the lower border of the ramus.
[168] Sliding calipers: Maximum external diameter at the angles; the
maximum points may, exceptionally, be either anterior to or a little
above the angle proper.