This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Surgery
Nipple inversion occurs due to involvement of 
Select and explain. 
A. Cooper ligament, B. Subareolar duct, C. Parenchyma of breast, D. Subdermal lymphatics
B: Subareolar duct
Answer: B: Subareolar duct 
Explanation: Mastitis in many cases the lactiferous ducts will first become blocked by epithelial debris leading to stasis; this theory is suppoed by the relatively high incidence of mastitis in women with a retracted nipple.Periductal fibrosis is a sequela of periductal mastitis and may result in nipple retraction.Schwaz surgery 15th edition pg: 509