Failure to recognize anatomical differences between fetuses and adults have led to the mislabeling of some structures. Sonographic images obtained both of intrauterine fetuses and in vitro clearly demonstrate a high amplitude echo that is lying medially in the head. The authors propose that the term 'falx cerebri' is inappropriate to describe the midline echo. As such terminology is based on faulty anatomical assumptions, it is suggested that the correct term of 'interhemispheric fissure' be utilized.
