Caldwell et al identified 4 main morphologic types of the human pelvis.
Key parameters:
(1) widest transverse diameter at the pelvic brim
(2) anterior to posterior diameter through the midline
(3) distance between the transverse line in #1 and the sacrum along the midline
(4) general shape
pelvic brim index =
= (anterior-posterior distance in cm) / (transverse diameter in cm) * 100
Main 4 types:
(1) anthropoid (dolichopellic) –resembling that of anthropoid apes
(2) gynecoid (mesatipellic) – typical for females
(3) android (brachypellic) – typical for males
(4) platypoid (platypellic)
|
|
Shape
|
Pelvic Brim Index (approximate)
|
Other
|
|
anthropoid
|
round to oval in antero-posterior axis
|
0.90
|
subpubic arch short
|
|
gynecoid
|
round to oval in transverse axis
|
0.79
|
wide subpubic arch
|
|
android
|
transverse line close to sacrum, portion anterior to transverse line triangular
|
0.79
|
narrow subpubic arch
|
|
platypoid
|
oval in transverse axis with flat anterior and posterior sides
|
0.59
|
wide subpubic arch
|
after Table 6-4, page 672, Gray's Anatomy
