A surgical instrument comprising: (a) an ultrasonic transducer ; (b) a shaft extending distally relative to the ultrasonic transducer along a longitudinal axis; and (c) an end effector arranged at a distal end of the shaft, wherein the end effector includes an ultrasonic blade , wherein the ultrasonic transducer is operable to drive the ultrasonic blade with ultrasonic energy, wherein the ultrasonic blade includes a distally extending tissue treatment portion configured to treat tissue with ultrasonic energy, wherein the tissue treatment portion includes: (i) a linear blade region extending parallel to the longitudinal axis, (ii) a curved blade region extending distally from the linear blade region along a curved path that deflects laterally from the longitudinal axis, (iii) an upper treatment side , (iv) a lower treatment side arranged opposite of the upper treatment side, (v) a first lateral side , wherein the first lateral side includes a first sweeping side surface , and (vi) a second lateral side arranged opposite of the first lateral side, wherein the second lateral side includes a second sweeping side surface, wherein the first and second sweeping side surfaces define respective first and second side edges of a transverse cross-section of the tissue treatment portion, wherein the first and second sweeping side surfaces are configured such that the first and second side edges are parallel to one another, wherein the end effector further comprises a clamp arm pivotably coupled to the shaft with a pivot pin , characterized in that the linear blade region includes at least one cutout feature positioned in alignment with the pivot pin. (a) an ultrasonic transducer ; (b) a shaft extending distally relative to the ultrasonic transducer along a longitudinal axis; and (c) an end effector arranged at a distal end of the shaft, wherein the end effector includes an ultrasonic blade , wherein the ultrasonic transducer is operable to drive the ultrasonic blade with ultrasonic energy, wherein the ultrasonic blade includes a distally extending tissue treatment portion configured to treat tissue with ultrasonic energy, wherein the tissue treatment portion includes: (i) a linear blade region extending parallel to the longitudinal axis, (ii) a curved blade region extending distally from the linear blade region along a curved path that deflects laterally from the longitudinal axis, (iii) an upper treatment side , (iv) a lower treatment side arranged opposite of the upper treatment side, (v) a first lateral side , wherein the first lateral side includes a first sweeping side surface , and (vi) a second lateral side arranged opposite of the first lateral side, wherein the second lateral side includes a second sweeping side surface, (i) a linear blade region extending parallel to the longitudinal axis, (ii) a curved blade region extending distally from the linear blade region along a curved path that deflects laterally from the longitudinal axis, (iii) an upper treatment side , (iv) a lower treatment side arranged opposite of the upper treatment side, (v) a first lateral side , wherein the first lateral side includes a first sweeping side surface , and (vi) a second lateral side arranged opposite of the first lateral side, wherein the second lateral side includes a second sweeping side surface, <EOS>