Objective:To provide anatomical basis for clinical application of human pectoralis major (P.major).Methods:The intramuscular nerve branches and muscle architectural features of P.major were dissected and observed.Results:1.The clavicular part(clavic.part) and sternal part of P.major had their anatomically distinct nerve supply.Some final terminal branches went along their course to each muscle slip.2.The average muscle mass

muscle length

fiber length and cross sectional area of the clavic.part of P.major were 45.9±10.8g

18.5±2.1cm

10.7±1.4cm and 4.1±1.1cm2

respectively and those of sternal part of P.major were 220.4±44.3g

21.4±1.6cm

17.2±2.6cm

12.4±3.1cm2

respectively.Conclusion:1.P.major could be divided into clavic.part and sternal part compartments according to the intramuscular nerve branches.2.The force produced by sternal part is 3 times as much as the clavic.part and the excursion produced by the former is 1.6 times as much as the latter.The two compartrnents of P.major could be used for muscle transplant respectively

so could each muscle slip.