Innervation of the Female Breast and Nipple: A Systematic Review and Meta-Analysis of Anatomical Dissection Studies

BACKGROUND: Primary cadaveric studies were reviewed to give a contemporary overview of what is known about innervation of the female breast and nipple/nipple-areola complex (NAC).

METHODS: We performed a PRISMA-compliant systematic review and meta-analysis (PROSPERO number CRD42020150250). We searched four electronic databases for studies investigating which nerve branches supply the female breast and nipple/NAC or describing the trajectory and other anatomical features of these nerves. Inclusion criteria for meta-analysis were at least five studies of known sample size and with numerical observed values. Pooled prevalence (PP) estimates of nerve branches supplying the nipple/NAC were calculated using random-effects meta-analyses; the remaining results were structured using qualitative synthesis. Risk of bias within individual studies was assessed with the Anatomical Quality Assurance (AQUA) checklist.

RESULTS: Of 3653 studies identified, 19 were eligible for qualitative synthesis and 7 for meta-analysis. The breast skin is innervated by anterior cutaneous branches (ACBs) and lateral cutaneous branches (LCBs) of the 2nd - 6th and the nipple/NAC primarily by ACBs and LCBs of the 3rd - 5th intercostal nerves. The ACB and LCB of the 4th intercostal nerve supply the largest surface area of the breast skin and nipple/NAC. The LCB of the 4th intercostal nerve is the most consistent contributory nerve to the nipple/NAC (PP 89.0%; 95% CI 0.80-0.94).

CONCLUSIONS: The ACB and LCB of the 4th intercostal nerve are the most important nerves to spare or repair during reconstructive and cosmetic breast surgery. Future studies are required to elicit the course of dominant nerves through the breast tissue.