Muscles of the Upper Trunk
Superior muscles of the upper front of the trunk. Labels: 1, sterno-hyoid; 2, sterno-cleido-mastoid; 3, sterno-thyroid; 4, sterno-cleido-mastoid; 5, edge of the trapezius; 6, clavicle; 7, clavicular origin of the pectoralis major; 8, deltoid; 9, fold of the pectoralis major of the anterior edge of the axilla; 10, middle of the pectoralis major; 11, crossing and interlocking of the fibers of the external oblique of one side with those of the other; 12, biceps flexor cubiti; 13, teres major; 14, serratus major anticus; 15, superior heads of external oblique interlocking with serratus major.
Miller, F. E.; Hunt, H. L.; McCormick, F.J.; Burr, B.; & King, M.L. Domestic Medical Practice: A Household Adviser in the Treatment of Diseases, Arranged for Family Use (Chicago: Domestic Medical Society, 1919) 28