["Thanatophoric dysplasia (TD), the most common of the congenital lethal skeletal dysplasias occurs sporadically in 1/64,000-100,000 live births. To the best of our knowledge, the in utero attitudes and behaviours of such babies with serial ultrasound scans have not been previously described.  We present the in utero third trimester sonographic behaviors of TD in a 22-year-old primigravida diagnosed at '32weeks' gestational age along with the clinical and radiographic characteristics.", 'The same radiologists to observe the behavior of a thanatophoric dwarfs did three fortnights serial ultrasound scans.', 'The baby was found to have short limbs that were constantly in rigid abduction, flexed at both elbows and knees, and demonstrated poverty of synchronous movements. The upper limbs were perpetually in embracing position during all scans. In addition, he was hyperactive, showing "yoyo" body movement and constantly hyper-extended neck. Postmortem radiograph was diagnostic of TD.'] Does prenatal third trimester sonographic behavior of a thanatophoric dwarf?