A surgical instrument, comprising: a body assembly; an ultrasonic waveguide extending through the body assembly along a longitudinal axis; an ultrasonic blade connected to a distal end of the ultrasonic waveguide; a clamp arm assembly configured to move from an opened position for receiving a tissue toward a closed position for clamping the tissue relative to the ultrasonic blade, wherein the clamp arm assembly includes: a clamp body, and a clamp pad connected to the clamp body facing the ultrasonic blade; a clamp arm actuator operatively connected to the clamp arm assembly and configured to selectively move from a first position toward a second position relative to the body to thereby respectively direct the clamp arm assembly from the opened position toward the closed position; characterised by an outer sheath radially surrounding at least a portion of the ultrasonic waveguide about the longitudinal axis, wherein the outer sheath includes: a sheath body operatively connected to the body assembly and affixed relative to the ultrasonic waveguide, wherein the sheath body further comprises a distal mount and a proximal mount extending upward from a lateral side of the sheath body within an inner portion, the distal and proximal mounts configured to pivotally mount the clamp arm assembly and clamp arm actuator, a cover removably received against the sheath body, and a sheath securement feature configured to detachably couple the cover to the sheath body such that the cover is configured to be selectively detached from the sheath body for accessing the ultrasonic waveguide and the inner portion within the outer sheath. a body assembly; an ultrasonic waveguide extending through the body assembly along a longitudinal axis; an ultrasonic blade connected to a distal end of the ultrasonic waveguide; a clamp arm assembly configured to move from an opened position for receiving a tissue toward a closed position for clamping the tissue relative to the ultrasonic blade, wherein the clamp arm assembly includes: a clamp body, and a clamp pad connected to the clamp body facing the ultrasonic blade; a clamp body, and a clamp pad connected to the clamp body facing the ultrasonic blade; a clamp arm actuator operatively connected to the clamp arm assembly and configured to selectively move from a first position toward a second position relative to the body to thereby respectively direct the clamp arm assembly from the opened position toward the closed position; characterised by an outer sheath radially surrounding at least a portion of the ultrasonic waveguide about the longitudinal axis, wherein the outer sheath includes: a sheath body operatively connected to the body assembly and affixed relative to the ultrasonic waveguide, wherein the sheath body further comprises a distal mount and a proximal mount extending upward from a lateral side of the sheath body within an inner portion, the distal and proximal mounts configured to pivotally mount the clamp arm assembly and clamp arm actuator, a cover removably received against the sheath body, and a sheath securement feature configured to detachably couple the cover to the sheath body such that the cover is configured to be selectively detached from the sheath body for accessing the ultrasonic waveguide and the inner portion within the outer sheath. a sheath body operatively connected to the body assembly and affixed relative to the ultrasonic waveguide, wherein the sheath body further comprises a distal mount and a proximal mount extending upward from a lateral side of the sheath body within an inner portion, the distal and proximal mounts configured to pivotally mount the clamp arm assembly and clamp arm actuator, a cover removably received against the sheath body, and a sheath securement feature configured to detachably couple the cover to the sheath body such that the cover is configured to be selectively detached from the sheath body for accessing the ultrasonic waveguide and the inner portion within the outer sheath.