I often reference the SEER manuals when I have detailed anatomical questions. (SEER = Surveillance, Epidemiology, and End Results Program from the National Cancer Institutes).
Although the SEER coding guidelines are more specific to tumor registries than claims coding/billing, I think there is some overlap and it is still a valuable educational tool.
The Breast Solid Tumor Rules document from SEER has some illustrations and descriptions for the central portion of the breast that might be helpful to reference:
https://seer.cancer.gov/tools/solidtumor/Breast_STM.pdf
The full index for SEER's Appendix C for all body sites can be found here:
https://seer.cancer.gov/manuals/2023/appendixc.html