What is the name of the widened area of the collecting duct located immediately behind the nipple?

The widened area of the collecting duct located immediately behind the nipple is referred to as the lactiferous sinus. This anatomical structure plays a crucial role in the lactation process by serving as a reservoir for milk. During breastfeeding, milk is stored in the lactiferous sinus and is released through the nipple when the infant suckles.

This area is particularly important because it allows for a more efficient transfer of milk from the breast to the baby, ensuring that milk can flow freely during feeding. The other options, while related to the anatomy of the breast, do not accurately describe this specific structure. For instance, milk ducts are channels that lead to the nipple, but they do not specifically indicate the widened area known as the lactiferous sinus. Lobules refer to the glandular tissue where milk is produced, and the areola is the pigmented area surrounding the nipple, neither of which directly describes the storage space for milk behind the nipple. Thus, lactiferous sinus is the correct term for the structure that holds milk in readiness for feeding.