CHAP. VII.
Of the PELVIS.
THIS being that Cavity in which the Womb is placed, and through which the INFANT passes in time of BIRTH; it is my Opinion that a distinct Knowledge of it is highly necessary for all MIDWIVES to accomplish their Practice: For without that Qualification, they cannot help committing a great many Blunders, and being guilty of innumerable Mistakes; since they must proceed upon gross Uncertainties, and use their Hands like MEN groping in the Dark, as hereafter will more plainly appear.
THIS is that Cavity betwixt the Ossa Innominata and Os Sacrum; which join themselves in the Posterior Part of it on each side, by Cartilages and Ligaments: so that they, forming there a strong and firm Juncture, compose this Cavity of the PELVIS, which is vulgarly call’d the Bason of the Womb.
THE upper Part of the Ossa Pubis forms the Borders of this Cavity before, and the Hanging forwards or bending down of the Os Sacrum makes Those of it behind; as the Ossa Ilia compose the same on each side.
THESE Ossa Ilia are (by some) call’d the Wings and Bounds of the PELVIS; but they are mightily mistaken, who imagine that they surround or encompass the PELVIS: For they are only annexed to it on each side, and more extended towards the Back than the Forepart. As they are also very much in the wrong, who think that the Cavity of the PELVIS extends in its Length, according to the Length of the Back-Bone: since it rises from the Bottom obliquely, ascending Forwards, and so proceeds, as if a Person might, through its Passage, easily touch the Navel.
IN fine, it is here Remarkable also, that we do not always find the largest PELVIS in Women of the largest Size, but often the quite contrary; for it differs as the INFANT does in Bulk, exactly answering to the Bigness of its Head: And in some Women it is Deeper, in some Larger, in some Broader, in some Flatter, in some more Oval, and in some at last Rounder. From whence arise sundry Observations both useful and necessary, for the better Information of MIDWIVES.