An end effector comprising a first jaw member having a first tissue contacting surface, a second jaw member having a second tissue contacting surface opposing the first tissue contacting surface of the first jaw member, the first and second jaw members moveable relative to one another between an open position and a clamped position, a knife configured to be moveable through the first and second jaw members along a longitudinal axis of the end effector and a detection assembly disposed within the first or second jaw members, the detection assembly being configured to determine the vasculature of tissue clamped between the first and second jaw members and prevent the knife from actuating based on the vasculature of the clamped tissue.
