Nikki writes: < My understanding of what happened back in the 1800s is that anatomists injected liquid wax into the ductwork through the nipple and when the wax hardened, the shape of what was then called "sinuses" was seen.> And it is interesting to view the drawing of that exquisite research using wax (which is still very much in use in histology today) alongside the artists drawing of the 'new anatomy' in Medela literature. Truly, I see definite similarities, myself. In fact, not too much real difference. <To me, the only way to reconcile what I have seen and experienced with the ancient anatomical work and Ramsey Geddes' new study is that the ducts near the areola are capable of swelling temporarily to accomodate an intermittent filling and emptying. That's why those places could be filled with wax, that's why they aren't seen as structures during ultrasound, and that's why I had little doughnuts around my nipples before feeds. A sinus is a pocket, with firm walls. Lactiferous sinuses have flexible walls, capable of more expansion than the other parts of the duct. What do you all think?> You are definitely thinking along some of the same lines I am, Nikki. There are various definitions of the word 'sinus', depending on the site, a few of which are: (American Heritage dictionary) 1. A depression or cavity formed by bending or curving. 2. Anatomy: a. a dilated channel or receptacle containing chiefly venous blood b. Any of various air-filled cavities in the bones of the skull, especially one communicating with the nostrils. 3. Pathology-a fistula leading from a pus filled cavity. In his textbooks, Haagensen, a famous breast surgeon showed a microscopic view, describiing lactiferous sinuses (in the resting breast) as having a characteristic, longitudinal accordion-pleated contour. 1. I invite anyone interested to google "Blue Histology" (which is the website of the University of Western Australia.) 2. Click the second listing "Blue Histology Searchable Large Images". 3. In the keyword space, type in Lactiferous sinus. 4. Then click on the square marked "02". You will get a very clear picture of a microscopic view of a cross section of the nipple of a resting breast which shows near its base, two lactiferous sinuses (in cross section). The histology/breast surgery/embryology specialties have adopted the term 'lactiferous sinus' and determined this as the official anatomical name of these structures that have been consistently identified in the resting breasts of not only adult women, but in children and in men. In adult women only, they are bounded by a thick wall of elastic tissue in the resting breast. Notice how much similarity there seems to be in the shapes on this Blue Histology slide and the outlined illustration of the duct in Ramsey et al's 2006 article in Pediatrics: "Ultrasound Imaging of Milk Ejection in the Breast of Lactating Women". The 21 women in these studies were all exclusively breastfeeding for at least one month, some up to six months. My question is "Why would nature have formed a structure found so consistently in immature and mature resting breasts of both sexes, and then have caused it to totally cease to exist when the organ was fully at work in its only known physiological function???" Could it be that the act of suckling for one month or more brings about changes in the pliability and thickness of the elastic tissue surrounding the walls of the sinuses, therefore changing their visibility on ultrasound to appear much the same as the ducts continuing inward toward the glandular tissue?? My current thinking is that the structure must be somehow specially constructed to permit optimum transmission of hydraulic pressures generated by robust suckling, so as to yield an adequate amount of milk for healthy infant growth, as well as sufficient removal of FIL to maintain adequate lactation. I concede that the MER is a powerful force, but we all know what often eventually happens to the milk supply when the baby is 'living off the MER' and not developing efficiency in actual suckling and generating sufficient additional hydraulic force for milk removal. I believe the ultimate answer will only be found under the microscope, by examining the cellular differences of the various ducts in the nipple-areolar complexes of the breast(s) of women in mid-to-late pregnancy, during the first month of postpartum, and then of fully breastfeeding women. Unfortunately, for these to be disease-free breasts, they would have to come from autopsy specimens, and have willing pathologists in-the-know about this controversy that has mainly pointed out the inadequacy of previous artists' conceptions. Such research would involve the ethics of obtaining cadavers of pregnant and/or lactating women, and this is a tremendous obstacle to surmount in this day and age, at least in this country. I have read articles on fairly recent breast research that has been carried out on cadavers. There is a protocol for obtaining a cadaver, and it is so formal that the pathologist supplying the cadaverous breast was given credit in the reference section of the article. Does anyone in our lactation community have any connections with medical school anatomy departments or pathologists who would be willing to explore this further under the microscope? While I think the redefinition of anatomy regarding the number of lobes/ducts will be particularly important in decisions on future breast reduction surgery in women of childbearing age, I found myself bristling at this statement in the Ramsay et al's 2005 article in the Journal of Anatomy: "Our failure to observe 'lactiferous sinuses' in the lactating breast suggests that the current explanation for the importance of positioning and attachment of the baby to the breast requires revision. In this connection, further investigation of the importance of positioning the nipple in the baby's mouth in relation to suck/breathe/swallow reflex would be of interest." Fortunately for our profession, there is at least one very experienced practitioner now involved in conducting such research. Jean ************** K. Jean Cotterman RNC, IBCLC Dayton, OH USA *********************************************** To temporarily stop your subscription: set lactnet nomail To start it again: set lactnet mail (or digest) To unsubscribe: unsubscribe lactnet All commands go to [log in to unmask] The LACTNET email list is powered by LISTSERV (R). There is only one LISTSERV. To learn more, visit: http://www.lsoft.com/LISTSERV-powered.html