UTERUS (DEVELOPMENT). 



647 



uteri into the upper part of the vagina be- 

 comes gradually less and less distinctly ascer- 

 tainable by the finger. The latter change is 

 commonly termed the "shortening of the cer- 

 vix;" but the conditions upon which it de- 

 pends, have not been very accurately examined, 

 and they are certainly not at all clearly or 

 adequately represented by the figures by 

 which the description of this process is usu- 

 ally accompanied. As much importance is 

 usually attached, in works on forensic and 

 obstetric medicine, to the changes in question, 

 it will be necessary here to examine a little 

 more closely the process by which this appa- 

 rent shortening of the cervix is produced. 



It is commonly said that no material altera- 

 tion, in the length of the cervix uteri, occurs 

 before the fifth month of gestation ; that, at 

 the sixth or seventh month, the uterine neck 

 has begun to shorten ; at the eighth month, 

 it is nearly, and at the end of the ninth month, 

 it is quite, obliterated. 



But while it is true that a lessening of the 

 projection of the cervix into the vagina com- 

 monly takes place in pregnancy (fig. 44-6.), 

 I can hardly coincide in the explanation which 

 is usually offered of this circumstance, namely, 

 that it is due to a gradual drawing up, as it 

 were, of the cervix, by which its walls become 

 added to those of the body of the uterus, for 

 the purpose of increasing the capacity of the 

 uterine cavity ; and that in this way the ute- 

 rine neck is gradually shortened, until it finally 

 disappears.* 



The accompanying fig. 446. exhibits the 

 condition of the cervix in a woman aged 

 thirty-seven, who, having previously borne 

 children, died of phthisis in the eighth month 

 of pregnancy. Here it will be perceived, that, 

 without any actual diminution of the length 

 of the cervix, which measured rather more 

 than one inch, still there is no projection of it 

 into the vagina ; but that it forms a flat roof 

 to that canal in the mode which is usually 

 described and explained as indicating the en- 

 tire absorption of the uterine neck. The true 

 explanation of this, as it appears to me, is, 

 that the apparent shortening of the neck is 

 caused not, at first, by any diminution of its 

 actual length, but by an increase of its breadth, 

 or its extension in the lateral direction, where- 

 by the projection of the lips into the vagina is 

 reduced to the smallest possible amount. The 

 rest of the process, upon which the shorten- 

 ing of the cervix depends, may be explained 



* See description of the figures in Gooch : "An 

 account of some of the most important diseases 

 peculiar to woman," p. 212; and Beck's Elements 

 of Medical Jurisprudence, oth edit. p. 128. 



Regarding this explanation, which had been given 

 by many preceding authors (see Mauriceau, torn. i. 

 p. 97. ; Smellie, vol. i. p. 183. et st?.), but which 

 Gooch was, I believe, the first to illustrate by dia- 

 grams, it appears to me that much imagination has 

 been exercised. The illustrations usually given are 

 evidently diagrams supplied for the purpose of 

 aiding the description of the process, as it has 

 been supposed to occur, from examination of the 

 part by the finger during life, but they give a very 

 imperfect notion of the actual state of the cervix 

 in pregnancy, as ascertained by dissection. 



by the variable condition of the internal os 

 uteri, or upper orifice of the cervix. If this 

 remains unyielding until the time of labour, 



Fig. 446. 



V 



Vertical section of the os and cervix uteri represented 

 in the last figure. 



v, walls of vagina; c, of cervix, and u, of uterine 

 body. The cervical canal is nearly filled by the 

 expanded pahnas plicatae. Half the natural' sis;e. 

 (Ad Nat.) 



then the finger, on being placed within the 

 cervix, traverses the whole length of the canal 

 before it reaches any part of the child ; and 

 the general form and substance of the cervix 

 being retained, the neck is said to be unob- 

 literated. Such is usually the state of parts 

 after repeated pregnancies. But if the in- 

 ternal or upper os yields readily, as it usually 

 does in the more advanced stage of a first 

 pregnancy, then the head of the child gradu- 

 ally settles down upon the lower or.fice, press- 

 ing aside the soft and yielding wall of the 

 cervix, which thus forms for it a shallow, cup- 

 like, or funnel-shaped recess, that may be so 

 far said to be added to the uterine cavitv ; and 

 the finger, on passing within the os readily, 

 touches the child, without having to traverse 

 any length of cervix. 



When, therefore, the term, shortening of 

 the uterine neck, is employed, it should be 

 understood to imply that change which takes 

 place from the hypertrophy and lateral exten- 

 sion of the vaginal portion of the cervix, com- 

 bined sometimes with a separation of the cer- 

 vical walls from each other, occasioned bv the 

 descent of the head of the child ; the degree 

 of this descent being regulated by the amount 

 of yielding of the internal os uteri. But it 

 does not signify any alteration in the anato- 

 mical condition of the cervix and body of the 

 uterus, which in every case retain their dis- 

 tinctive characteristics to the end of preg- 

 nancy : while the dilatation of the cervical 

 canal is only an occasional occurrence, limited 

 to the last stage of pregnancy, and having 

 nothing to do with that apparent shortening 

 which begins after the fifth month. 



Position actual and relative. The enlarge- 

 ment which the uterus undergoes during ges- 

 tation, occasions of necessity very considerable 

 alterations in its actual and relative position. 

 On the occurrence of pregnancy, the organ, at 

 first concealed within the pelvis, sinks, by its 

 increased weight, lower than usual within that 

 T T 4 



