The breast is supplied with cutaneous fibers from the anterior and lateral cutaneous branches of the third through fifth intercostal nerves. The autonomic components of these nerves supply the smooth muscles of the skin, nipple, acini and blood vessels. The parenchymal tissue is regulated by hormones.  Nerve supply is; these provide sensory and sympathetic fibers supplying the skin, smooth muscle of the areola and nipple, blood vessels, and mammary gland.

Nerve supply of the breast

This image shows the nerve supply of the breast consisting of the anterior and lateral branches of the 3rd through 5th intercostal nerves.  The nipple is part of the T4 dermatome.  Courtesy Ashley Davidoff MD  78380pb07d

Applied Anatomy

      Nipple sensitivity to sucking is the important starting point of lactation. The nipple is supplied by the 4th dermatome. The stimulus created by the suckling infant is transmitted via the 4th intercostal nerve.  Once the sensation of sucking is sensed at a neural level, there is a complex series of neural and hormonal events that cause the acini to contract, the nipple to become erect, sebaceous glands to secrete an oily protection, and lactiferous ducts to straighten enabling a smooth flow of milk from the acini and ducts to the infant.  There is also a supratentorial feeling of pleasure created by this compound event that further enhances a most important biological event.

Neurofibromatosis

This is a case of multicentric tumors of the nerve sheaths in a patient with  is characterized by extensive diffuse, bilateral soft tissue nodules.  Courtesy Priscilla Slanetz MD MPH  27985