Anatomic Relationship of the Pectoralis Major and Minor Muscles: A Cadaveric Study

Goals/Purpose: Although the anatomy of the individual pectoralis major and minor muscles has been described previously, never before has the anatomic relationship between these muscles been investigated. The goal of this study was to identify the anatomic relationship of the costal origins of the pectoralis major and minor muscles.

Methods/Technique: Bilateral thoracic wall dissection was completed in 102 cadavers. In each dissection the chest wall soft tissue was removed, and the distance between the costal origins of the pectoralis major and the pectoralis minor muscles was measured. 

Results/Complications: Two-hundred two pectoralis major muscles were lifted in 102 cadavers (F: 49, M: 53) in order to expose the costal origin of the pectoralis major and minor muscles. Distances between pectoralis major and the pectoralis minor muscles were separated into three categories: less than 1 cm, between 1 cm and 3 cm, and greater than 3 cm. Forty-nine (24%) pectoralis muscle dissections displayed a distance of less than 1 cm between costal muscle origins. Eighty-three (41%) showed an intermediate distance of between 1 cm and 3 cm while the remaining seventy (35%) were over 3 cm. No significant difference was observed in these percentages in regards to gender. Ten cadavers displayed asymmetry in pectoralis muscle origin distance. Eight specimens displayed shared fibers between pectoralis major and minor muscles.

Conclusion: The anatomic relationship between the costal origin of the pectoralis major and minor muscles is highly variable. Understanding this spatial relationship has important implications in cosmetic and reconstructive breast surgery.