2p3 THE FCETUS. 



to the lower end of the sternum, and six inches from the extremity 

 of the sternum to the pubis. From the top of one acromion to the 

 other we find four inches and a half, which may be easily reduced 

 to three inches and a half by squeezing the shoulders together. 

 The greatest antero-posterior thickness of the thorax is four inches 

 and a half, while there are only three inches from one crista of the 

 ilium to the other. 



§. IV. Of the Foetal Head, at Term. 



519. The head, being of all parts of the foetus, the largest and 

 most incompressible, ought to be studied with the most particular 

 care. The bones of which it is composed, its articulations, its 

 diameters, its motions, and the degree of reduction it is susceptible 

 of, ought to be perfectly known to the practitioner who desires not 

 to be more dangerous than useful in applying the assistance of the 

 art to cases of dystocia. It is composed, as in the adult, of the 

 cranium, which is its most interesting part, and of the face, which is 

 as yet but little developed, and whose pieces consist of the ossa nasi, 

 the ossa malarum, the ossa raaxillaria superiora, the ossa unguis, 

 the ossa palati, the ossa spongiosa inferiora, the vomer, and the os 

 maxillare. 



520. Form. The head of the foetus, chiefly remarkable from the 

 flexibility of its vault, exhibits in its ensemble the form of an oval, 

 the attitude of which has occasioned a sort of literary quarrel be- 

 tween MM. Capuron and Van Solingen: the former of these authors 

 insists that the large extremity of the head is turned backwards, 

 while the latter, who is also followed by M. Duges, places it, on the 

 contrary, in -front. If the external occipital protuberance occupies 

 the centre of the strait in labor, it is diflScult not to agree with the 

 Dutch accoucheur, that the large extremity of the oval is represented 

 by the face; but when we take hold of the head by the chin its large 

 extremity is undoubtedly to be found posteriorly. In this case, as 

 in many others, the dispute is rather about words than things; both 

 sides are right, and both are wrong in some respects. However, 

 by reflecting that all the diameters of the posterior part of the head 

 are three inches and a half in length, while the longest of those of 

 the face is only three inches at most, it will be evident that we ought 

 to adopt the opinion of our countryman, and say that the large ex- 

 tremity of the foetal head is formed by the occiput, 



521. Diameters. The axes or diameters of the head are imagi- 

 nary lines, which pass through it in determinate directions. They 

 may be multiplied ad infinitum; but those only that are liable to be 

 placed in certain relations to tlie axes or diameters of the pelvis, de- 



