1. An ultrasonic diagnostic apparatus, comprising: an image generating unit configured to control an ultrasonic probe to execute echocardiography and to generate an echocardiographic image including an aorta; a position sensor configured to generate a positional data signal pertaining to a spatial coordinate position and a scanning direction/orientation; an acquiring unit configured to acquire a heart area image including the aorta; an extracting unit configured to extract an artery region based on the heart area image; a flap identifying unit configured to identify a flap region based on the artery region; a first synthesizing unit configured to synthesize information on the flap region onto the artery region to generate a first synthesized image; an alignment processing unit configured to perform processing to align an imaging region in the echocardiography on the heart area image based on the positional data signal; and a second synthesizing unit configured to synthesize information that indicates the imaging region processed for alignment onto the first synthesized image to generate a second synthesized image.