How many lactiferous ducts open into nipple
The gland consists of 15 to 20 lobes.Each lobe is a cluster of alveoli,and is drained by a lactiferous duct.The lactiferous ducts converge towards the nipple and open on it.Near it's termination each duct has a dilatation called a lactiferous sinus. Ref.B D Chaurasia's human anatomy.vol.1
0-10
15-20
25-50
50-75
Thorax