lower uterine segment
DESCRIPTION
an overview of the uterine anatomy with clinical implications with regards to placenta praeviaTRANSCRIPT
![Page 1: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/1.jpg)
NurFakhriyyah, LokemanHazli, Alia Nadhirah
Associate Professor Dr Hanifullah Khan
04/12/231
![Page 2: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/2.jpg)
04/12/232
*This presentation aims to
*Explain what the Lower Uterine Segment (LUS) is
*An outline of it’s anatomical and histological features
*The implications of the LUS in clinicalpractice
![Page 3: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/3.jpg)
04/12/233
*Uterine enlargement in pregnancy
*by hypertrophy, hyperplasia and stretching of the muscle fibres.
*from 50-60g to almost 1000g at term
*At 7 weeks - the size of an egg;
*At 10 weeks it is the size of an orange and fills the entire pelvis.
*At 12 weeks it rises out the pelvis and palpable abdominally just above the symphysis pubis
![Page 4: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/4.jpg)
04/12/234
*The lower uterine segment (LUS) is the part of the uterus and the upper cervix which lies between the attachment of the peritoneum of the uterovesical pouch superiorly & the internal cervical os inferiorly.
*The isthmus of the uterus, the lower extremity of which joins with the cervical canal and during pregnancy expands to become the lower part of the uterine cavity
![Page 5: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/5.jpg)
04/12/235
*With increasing gestation, there is increased stretching of the uterine muscle fibres.
*This results in the formation of the lower segment in the 3rd trimester (28 – 40 weeks).
![Page 6: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/6.jpg)
04/12/236
![Page 7: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/7.jpg)
04/12/237
*This part of the uterus is thinner contain less muscle fibres and blood vessels.
*This is the site for caesarean section incision.
*The placenta is attached to the more vascular and thicker upper segment.
![Page 8: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/8.jpg)
![Page 9: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/9.jpg)
*In such cases, the placenta is attached partially or completely to the LUS
*Placental attachment is disrupted as this area gradually thins in preparation for the onset of labor. *bleeding occurs at the
implantation site as the uterus is unable to contract adequately and stop the flow of blood from the open vessels.
![Page 10: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/10.jpg)
04/12/2310
![Page 11: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/11.jpg)
*Muscles @ LS:
*relatively weaker layer of muscle
*less blood supply, compared to the upper segment.
*Caesarean operation is done in the lower segment (across the top of the pubic hairline)
*less likely to cause excessive bleeding.
![Page 12: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/12.jpg)
04/12/2312
*The LUS is an important anatomical part of the uterus
*It has anatomical and functional aspects that can be utilized to produce a better outcome in pregnancy and labour
*Attachment of the placenta to the LUS leads to a risk of bleeding
![Page 13: Lower uterine segment](https://reader038.vdocuments.us/reader038/viewer/2022102414/556bddd2d8b42ab2138b50b2/html5/thumbnails/13.jpg)
04/12/2313
*Obstetrics by Ten Teachers
*http://www.pregnancy-labour.info/2009/04/changes-in-uterus-during-pregnancy.html