C-axis: a growth vector for the maxilla.
Based on M-point, defined as the center of the largest circle that is tangent to the superior, anterior, and palatal outlines of the maxilla in the sagittal view, a growth axis and its direction are described for each gender from age 7.4 to 18.75 years. Growth increments along the C-axis, defined by sella-M-point, are described by regression formulas with correlation coefficients of 0.618 for females and 0.669 for males. The vector (direction) of the growth axis, defined by the angle S-M-C-axis, increases in females from 42.21 degrees at 7.4 years to 44.47 degrees at 18.75 years, with a standard deviation of 3.55 degrees. In males, it increases from a mean of 41.69 degrees at 7.6 years to 45.55 degrees at 18.6 years, with a standard deviation of 2.74 degrees. This is based on 172 serial lateral cephalograms of 20 females and 174 serial lateral cephalograms of 19 males. The C-axis incremental growth change and its vector offer a means of quantifying complex maxillary growth in the sagittal plane via cephalometric measurements relative to and coordinated with other craniofacial structures.
Braun
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S
Vanderbilt University Medical Center, USA.
Rudman
R T
RT
Murdoch
H J
HJ
Hicken
S
S
Kittleson
R
R
Ferguson
D J
DJ
D000293:Adolescent; D000375:Aging; D002508:Cephalometry / Q000706:statistics & numerical data; D002648:Child; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging / Q000254:growth & development*; D015588:Observer Variation; D011859:Radiography; D011897:Random Allocation