Fetal abnormalities
shortening of the bones of the hands or feet.
crescent shape to the cerebellum displayed with a coexisting neural tube defect.
protrusion of the posterior bladder wall through a defect in the lower abdominal wall and anterior wall of the urinary bladder.
band of white matter tissue connecting the cerebral hemispheres; serves a function in both learning and memory.
protrusion or bulging of the forehead associated with hydrocephalus.
overt enlargement of the lateral ventricles secondary to an increase in intracranial pressure.
abnormally widespread position of the orbits.
abnormally close position of the orbits.
appearance of the dilated bladder superior to the obstructed male urethra.
concavity to the front bones of the fetal cranium; associated with spina bifida.
shortening of the middle portion of a limb.
shortening of all portions of a limb.
a developmental defect of the central nervous system in which a hernial sac containing a portion of the spinal cord, its meninges, and cerebrospinal fluid protrudes through a congenital cleft in the vertebral column.
distance between the calvaria and posterior skin line.
protrusion of nasal tissue above the orbits
shortening of the proximal portion of a limb.
enlargement and upper displacement of the third ventricle associated with agenesis of the corpus callosum.
ventricular enlargement characterized by excessive cerebrospinal fluid within the ventricles.
structure located between the hemispheres of the cerebellum.
| ABNORMALITY | INFORMATION | SONOGRAPHIC FINDINGS | DIFFERENTIAL CONSIDERATIONS |
| Acrania | Abnormal migration of mesenchymal tissuesSkull is absentBrain is presentElevated alpha-fetoprotein levelsCoexisting spinal defects, clubfoot, cleft lip and palate | Lack of hyperechoic bony calvariaBrain tissue developmentProminent sulcal markings | AnencephalyOsteogenesis imperfecta |
| Agenesis of the corpus callosum | Failure of callosal fibers to form a normal connectionMay be partial or completeAssociated with multiple anomalies | Dilation of the third ventricleOutward angling of the frontal and lateral horns (steer sign)Dilation of the occipital hornAbsent cavum septum pellucidi | Holoprosencephaly |
| Arachnoid cyst | Congenital abnormality of the pia-arachnoid layerA result of trauma, infarction, or infection | Splaying of cerebellum hemispheresNormal vermis | Dandy-Walker cystProminent cisterna magnaVein of Galen aneurysmImproper technique |
| Arnold Chiari Type II malformation | Displacement of the cerebellar vermis, fourth ventricle, medulla oblongata through foramen of magna into the upper cervical canal | Compressed shape to the cerebellum (banana sign)Obliteration of the cisterna magnaVentriculomegalyLemon-shaped cranium | Spina bifida |
| Dandy-Walker syndrome | Congenital malformation of the cerebellum with associated maldevelopment of the fourth ventricleResult of alcohol abuse, autosomal recessive disorder, or viral infection | Enlarged posterior fossaSplaying of the cerebellar hemispheresComplete or partial agenesis of the vermisCisterna magna >1.0 cm in diameterVentriculomegaly | Prominent posterior fossaArachnoid cystVein of Galen aneurysmArtifact |
| Hydranencephaly | Destruction of the cerebral cortex resulting from vascular compromise or congenital infection (usually carotid area)Brain tissue is replaced by cerebrospinal fluid | Anechoic brain tissueNot associated with other abnormalitiesPresence of the falx cerebriBrain stem usually sparedChoroid plexus may be displayedVariable presence of the third ventricle | Severe hydrocephalusHoloprosencephaly |
| Hydrocephalus (ventriculomegaly) | Increase in ventricular volume caused by outflow obstruction, decrease in cerebrospinal fluid (CSP) production, or overproduction of CSPOccipital horn dilates first | Ventriculomegaly is generally symmetricalMild EnlargementLateral ventricle measuring 10-15 mmSevere EnlargementLateral ventricle measuring >15 mmDangling of the choroid plexusEchogenic rim of solid brain tissue | HydranencephalyHoloprosencephalyImproper technique |
| Holoprosencephaly | Group of disorders arising from abnormal development of the forebrainStrongly associated with Trisomy 13AlobarMonoventricular cavityMost severe formSemilobarMonoventricular cavityMilder formLobarTwo large lateral ventriclesMildest form | AlobarLarge central single ventricleFused thalamiAbsence of cavum septum pellucidi, falx cerebri, corpus callosum, and third ventricleNormal cerebellumHypotelorismCyclopiaProboscisSemilobarLarge central single ventricleOccipital and temporal horns may be presentVariable development of the falxAssociated with cleft lip and palateLobarTwo large lateral ventriclesAbsent cavum septum pellucid, and cavum callosum | Severe hydrocephalusHydranencephaly |
| Lemon shape | May be a normal findingAssociated with spina bifida | Bilateral indentation of the frontal bones | Dolichocephaly |
| Microcephaly | Overall reduction in brain sizeChromosomal aberrationIntrauterine infectionDifficult to detect before 24 wks | Small biparietal diameter (BPD) and head circumference (HC)Decreased HC/abdominal circumference (AC) ratioSloping forehead | AnencephalyEncephalocele |
| Prosencephaly | A result of infarction or hemorrhage of the brain | Anechoic mass within an area of brain tissueMidline brain shift | Cystic leukomalacia |
| Strawberry shape | Associated with Trisomy 18 | Flattened occiput diameter and narrowing of the frontal portion of the skull | Brachycephaly |
| DEFECT | INFORMATION | SONOGRAPHIC FINDINGS | DIFFERENTIAL CONSIDERATIONS |
| Anencephaly | Failure of the cephalic end of the neural tube to close completelyPortions of the midbrain and brain stem may be present.Most common neural tube defectElevated alpha-fetoprotein (AFP) levelsAssociated with malformations of the spine, face, feet, and abdominal wall | Absence of the cranial vaultBulging eyes (froglike face)Rudimentary brain tissue herniating from the defectMacroglossiaPolyhydramniosIncrease in fetal activity | Severe microcephalyAcraniaEncephaloceleAmniotic band syndrome |
| Caudal regression | Structural abnormality of the caudal end of the neural tubeMore common in patients with diabetesAssociated with genitourinary, gastrointestinal, and cardiovascular abnormalities | Absent sacrumFused pelvisShort femurs | Skeletal dysplasia |
| Encephalocele | Normal AFP levelPresence of brain in a cranial protrusionMore commonly arises in the occipital region | Spherical fluid-filled or brain-filled sac extending from the calvariaBony calvarial defect | Cystic hygromaCloverleaf skull deformityAmniotic band syndromeMicrocephaly |
| Spina bifida | Failure of the neural tube to close completelyOccultaDefect is covered by normal soft tissueNormal AFP levelRarely diagnosed with ultrasoundApertaDefect is uncoveredElevated AFP levelAssociated with cleft lip and palate, cardiac defects, encephalocele, gastrointestinal anomalies, and clubfoot | CoronalDisappearance of the middle hyperechoic lineWidening of the external hyperechoic linesSagittalPosterior hyperechoic line and overlying soft tissues are absentTransverseOutward splaying of the lateral posterior ossification centers into a “U” or “V” shapeCystic or complex mass protruding from spinal defectCerebellum takes on a crescent shape (banana sign)Frontal bones are concave (lemon shaped) | Sacrococcygeal teratoma |
| ABNORMALITY | INFORMATION | SONOGRAPHIC FINDINGS | DIFFERENTIAL CONSIDERATIONS |
| Anophthalmia | Lack of fusion of the maxillary prominences with the nasal prominence on one or both sidesFailure of the optic vesicle to form | Absence of the globe or often the orbit | Poor fetal positionTechnical error |
| Cyclopia | Midline fusion of the orbitsAssociated with holoprosencephaly, Trisomy 13, microcephaly, Williams syndrome | Single midline orbit | Poor fetal positionTechnical error |
| Facial cleft | Defect of the upper lipMost common facial abnormality | Anechoic defect between the upper lip and nostrilsPolyhydramniosSmall stomach | Technical error |
| Hypotelorism | Orbits placed closer together than expected | Abnormally small interocular distance for gestational age | Poor fetal positionTechnical error |
| Hypertelorism | Orbits placed wider apart than expectedAssociated with Trisomy 18, Noonan syndrome, Median cleft syndrome, craniosynostosis, and anterior cephalocele | Abnormally wide interocular distance for gestational age | Poor fetal positionTechnical error |
| Macroglossia | Associated with Beckwith-Wiedemann and Down syndromesPersistent protrusion of the tongue | Persistent protrusion of the fetal tonguePolyhydramnios | Normal tongueUmbilical cord |
| Micrognathia | Hypoplastic mandibleAssociated with Trisomy 18 | Small receding chin and lower lipPolyhydramniosProtrusion of the upper lip | Technical errorNormal chin |
| ABNORMALITY | INFORMATION | SONOGRAPHIC FINDINGS | DIFFERENTIAL CONSIDERATIONS |
| Cystic hygroma | Developmental defect of the lymphatic systemAssociated with chromosomal abnormalities, fetal hydrops, and fetal heart failure | Multilocular anechoic cervical massThin surrounding membraneNo cranial defectContinuous with abnormal skin and subcutaneous tissues | EncephaloceleCystic teratomaNormal umbilical cordThyroglossal cystNuchal edema |
| Nuchal edema | Thickening of the nuchal foldAssociated with chromosomal abnormalities | Anechoic posterior cervical massMidline septum | Cystic hygroma |
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| ABNORMALITY | INFORMATION | SONOGRAPHIC FINDINGS | DIFFERENTIAL CONSIDERATIONS |
| Cystic adenomatoid malformation | Abnormal formation of the bronchial treeReplacement of normal pulmonary tissues with cystsMay be associated with renal or gastrointestinal abnormalities | Simple or multiloculated cystic chest massMediastinal shiftDiaphragm is visible and intactFetal hydropsPolyhydramniosUsually unilateral | Diaphragmatic herniaPleural effusionPericardial fluid |
| Ectopia cordis | Partial or complete displacement of the heart outside of the thorax | Small thoraxHeart located outside of the thoraxExtrathoracic pulsating mass | Acardiac twinDiaphragmatic hernia |
| Ebstein anomaly | Displacement of the septal and posterior leaflets of the tricuspid valves into the right ventricleVariable in degree | Four-chamber heartEnlargement of the heart (especially right atrium)Regurgitation across the tricuspid valve with Color and Spectral Doppler | Tetralogy of FallotVentricular septal defect |
| Diaphragmatic hernia | Diaphragm fails to close allowing herniation of the abdominal cavityAssociated with cardiac, renal, chromosomal, and central nervous system anomalies | Stomach or liver located in the thoraxInability to visualize normal diaphragmMediastinal shiftSmall abdominal circumferencePolyhydramniosUsually unilateralLeft-sided defect more common | Cystic adenomatoid malformation |
| Pleural effusion |