The Spatchcock Capon

An academic director is hired at a new medical school and it becomes her goal to implement a new curriculum. Based on her anatomical experience or lack thereof, she intends to make gross anatomy an elective and/or let students learn anatomy exclusively using artificial intelligence. To promote her new curriculum, she invites a half dozen students to her office kitchen and plans to demonstrate how to spatchcock a chicken even though she has no culinary training. While splitting “the chicken” (she had actually purchased a capon weighing well over 15 pounds), the new knife she purchased for the procedure slips out of her hand and impales her chest just below mid-clavicle. The knife appears to have entered her chest almost one inch.  Immediately there is a gush of blood and a first-year medical student who has just finished her gross anatomy course reaches toward our academic director to apply pressure. The medical student asks the director to lie down saying that she will call an ambulance to rush her to the ED. The director is barely able to speak, but she assures everyone she is ok and not to bother. The medical student insists on rushing the director to the ED. Which of the indicated structures is the medical student fearing the director may have injured with the flying knife?

A penetrating midclavicular injury is most likely to injure which of the following?