Lactiferous sinuses
Sinus lactiferi
- Related terms: Lactiferous sinus
Definition
The lactiferous sinuses (also called ampullae or galactophores) are dilated segments of the lactiferous ducts located beneath the areola of the breast. Each breast contains approximately 15–20 lactiferous ducts, and each duct widens into a lactiferous sinus just before converging at the nipple. These sinuses serve as small reservoirs where breast milk accumulates during lactation before being expressed through the nipple pore during breastfeeding or milk ejection.
Anatomical details:
Located between the glandular tissue of the breast and the nipple opening
Each sinus corresponds to one of the breast's lobes and its associated ductal system
During lactation, the sinuses distend with milk and are compressed by the infant's jaw and tongue during suckling, facilitating milk flow
On ultrasound, they appear as hypoechoic tubular structures beneath the areola
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