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to be well developed and of a symmetrical shape, any pressure applied from behind forwards would produce irregularity. With a perfect palate such pressure will in the upper jaw very often produce a bulging out of the bicuspids; in the cleft palate, the median portion (which in the natural state ties the two piers together) being absent, the molars are to some extent separated, while the first bicuspids are approximated.
As curiously corroborative of this view of the matter, we would submit the instances of irregularity that occur in the lower jaw, where we have a condition somewhat analogous to the cleft palate and imperfect arch of the upper jaw. In consequence of the absence of any strong tie between the two angles of the dental arch in the inferior maxilla, it is often seen when the wisdom teeth are erupted, and all the other teeth are perfect and in good position, that the bicuspids will in some rare cases sink below the level of the rest of the lower teeth, in consequence of the absorption produced by the pressure from behind forwards, and in many cases an approximation of them takes place towards each other identical with that which we have brought forward as occurring from a similar cause in the upper jaw.
This is further corroborated by the fact, that in the first dentition, in the simple cleft there is no deformity of the dental arch. This is shown in fig. 3, the model of a child's mouth at four years of age, and drawings of several other casts could be shown in proof of the same fact.
On these grounds, therefore, we would, with all deference, submit this view of the case to our professional readers.
Whether cleft palate is hereditary or not it seems impossible to determine, though from the evidence we have in hand we should come to the conclusion that it is not. Still, unless one could obtain accurate records of ancestry for three or four degrees of removal, it would be impossible to assert anything with certainty. We feel, however, that it may confidently be asserted that this deformity cannot be produced from any impression received by the mother during pregnancy, for in every case which has come
immediately under our notice, where one of the parents has had cleft palate, all the children born have been perfectly developed, even though dread on the part of the mother of transmitting the deformity has been most constant.
In one case, curiously enough, there are three members of one family with cleft palate, one seventeen years of age, the other thirty, and the
, third thirty-five; the first and last are ladies, the other a gentleman, who is married, and has a family without any trace of the father's deformity. In these cases no instances of cleft palate could be found either among ancestors or collateral branches of the family. It will be interesting to watch whether in the following generations any traces spring up again, for no cases of immediate transmission seem to have been placed on record.
It is strange, and, so far as we are aware, quite unaccounted for, that the majority of cases are of fair complexion and nervous temperament, while very few are of a dark complexion and lymphatic temperament. Whether this conclusion will be justified by a larger field of observation we cannot of course say; but in a great number of instances we have found it to be so.
We have always deemed it a matter of great comfort to parents to be able to assure them that there is little liability of their children inheriting their deformity; and as yet we have seen no reason to render this assurance unreliable.
ON THE ANATOMY AND PHYSIOLOGY OF CLEFT PALATE.
For the anatomy of cleft palate we are almost entirely indebted to Sir William Fergusson, who some years back had the rare good-fortune to come across a case in the dissecting-room, an account of which he gave in a paper read before
a the Medical and Chirurgical Society on the 10th December, 1844. On the conclusions which he came to as to the physiology of the parts he based his method of treatment for this condition of the palate, and put forward the plan of dividing the levator palati muscle, in order to obtain perfect control over the palate during the operation.
The value of this account of the anatomy and physiology of cleft palate cannot be overestimated, since, in addition to the light it threw upon the surgeon's work, it has of late years become the basis of treatment by mechanical means.
Under these circumstances we feel we cannot do better than give to our readers an extract from the Society's Transactions (for 1845), in Sir William Fergusson's own words :
“Few have had the opportunity of dissecting a cleft palate, and some notice of a specimen in my possession will form an appropriate introduction to the views developed in this paper. The fissure in this instance implicates a portion of the hard as well as the whole soft palate, and is such as the surgeon frequently meets with in practice. The specimen was procured in the dissecting-room from the mouth of an aged female subject.
“In the examination of this preparation there are several marked differences between it and the parts in a more natural state. The superior constrictor muscle is more fully developed than under ordinary circumstances, and its upper margin, extending between the basilar process of the occipital bone and the internal pterygoid plate is particularly distinct. This part of the muscle forms a sort of semicircular loop, in which the levator palati muscle seems to be suspended.
“The pharynx has been laid open by a perpendicular incision through the constrictors in the mesial line, and the movable portion of the palate has been dissected on one side. The circumflexus, or tensor palati, differs little from the natural condition, and the levator palati is much as it is usually met with, its lower end spreading out in all directions on the soft palate. The palato-pharyngeus consists of two distinct bundles