Figure - 11-23ab. Lateral cleft lip. (A) Coronal scan through the nose (N) demonstrates a small, hypoechoic region lateral to the midline in the upper lip, which extends to the nares and corresponds to a lateral cleft lip (C). (B) Specimen from another fetus demonstrates typical findings of isolated lateral cleft lip extending lateral of midline in the upper lip to the nares. 图11-23ab 一侧唇裂 A 鼻部（N）的冠状切面显示上唇中线一侧的小的无回声区，向鼻部扩展，符合一侧唇裂（C）的特征。B 另一胎儿标本显示典型的单纯一侧唇裂，从上唇中线一侧扩展至鼻孔
Figure - 11-24. Lateral cleft lip and palate. Coronal ultrasound through the maxilla demonstrates a larger defect (curved arrows) lateral to midline corresponding to a cleft lip and cleft palate. N, nose; O, orbit. 图11-24 一侧唇腭裂 上颌骨冠状超声切面显示大的从一侧到中线的缺损（弧箭头），符合唇腭裂的特征。N 鼻 O 眼眶
Bilateral Cleft Lip and Palate Bilateral cleft lip and palate may be identified ultrasonographically before 16 weeks' gestation.(20) Complete bilateral cleft lip and palate may be easily recognizable ultrasonographically because the appearance of the face is sufficiently disrupted, even in the early second trimester.(70) Parasagittal and sagittal profile views may assist in identifying premaxillary protrusion, which may be the first or primary clue to the presence of a facial abnormality, permitting early or prenatal identification of bilateral cleft lip and cleft palate(72-74) (Fig. 11-25, Fig. 11-26A-B and Fig. 11-26C). Premaxillary protrusion occurs only with bilateral complete cleft lip and palate. The paranasal echogenic mass represents protruding bone and alveolar structures within the premaxillary protrusion. The mass typically is inferior to the nose, irregular in shape, and of similar echogenicity to bone and alveolar structures. A soft tissue mass protruding outward and upward from the upper lip on sagittal views of the face may also be seen in some fetuses, with premaxillary protrusion corresponding to an everted upper lip.(73,74) Nyberg and colleagues(68) categorized bilateral cleft lip and palate into those with premaxillary protrusion and those with a hypoplastic midface. Premaxillary protrusion is most apparent on midline sagittal views but can also be seen on coronal or transverse views.(68) The paranasal echogenic mass appears most prominent during the second trimester, at a time when the cleft is small and often difficult to detect. With advancing gestational age, the mass may become less prominent.(74) In cases of bilateral cleft lip and palate associated with a hypoplastic midface, premaxillary protrusion is conspicuously absent. The ultrasonographic appearance is consistent with absence of the primary bony palate but preservation of the midline lip.(68) At times, these may be difficult to distinguish from median cleft lip and palate, and this appearance has a high rate of associated chromosomal abnormalities similar to median cleft lip and palate.
Figure - 11-25. Bilateral complete cleft lip and palate. Frontal and sagittal view demonstrating the position of the protruding premaxillary mass. The echogenic mass seen on prenatal ultrasound is related in part to the alveolar bone and teeth, which have migrated anteriorly. 图11-25 双侧唇腭裂 额面和矢状面显示前突的颌骨团块位置。额面超声可以看到团块回声与向前移位的齿槽骨和牙齿有关。