. An American text-book of obstetrics. For practitioners and students. of the force C, whilethe occiput receives the force A, plus the greaterpart of the force C. 434 AMERICAN TEXT-BOOK OF OBSTETRICS. to well-known mechanical laws, be exerted), the construction of the parallel-ogram of forces shows that the line T (whose length represents the portionof the resistance B which is exerted in direct opposition to descent) is muchgreater than that of the line T (which represents the efficient proportionof the resistance B). From this it is evident that the occipital end of thehead is exposed not on
. An American text-book of obstetrics. For practitioners and students. of the force C, whilethe occiput receives the force A, plus the greaterpart of the force C. 434 AMERICAN TEXT-BOOK OF OBSTETRICS. to well-known mechanical laws, be exerted), the construction of the parallel-ogram of forces shows that the line T (whose length represents the portionof the resistance B which is exerted in direct opposition to descent) is muchgreater than that of the line T (which represents the efficient proportionof the resistance B). From this it is evident that the occipital end of thehead is exposed not only to greater force from above, but also to less resistancefrom below, while the sincipital end is opposed by greater resistance andreceives a less amount of propulsive power—conditions which can only resultin a more rapid advance of the occiput. As soon as partial flexion has been accomplished a second effect of theirregular shape of the head comes into play, and there must suchimportance as is due to it. Figure 249 represents a partially-flexed head.
Size: 1757px × 1421px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
