Diameters of the vertex, brow, and face presentation

(A) Occipital presentation with widest diameter suboccipitobregmatic, mean length 9.5 cm.
(B) Brow presentation with widest diameter mentoparietal or mentovertical, mean length 13.4 cm.
(C) Face presentation with widest diameter trachelobregmatic or tracheloparietal, mean length 12.6.