Normal fetal anatomy

Anatomy Scan• Indications

– Identify fetal abnormalities– Identify IUGR– Dating– Placental localisation

• Timing– 16-20 weeks– 22-24 weeks

• Machine– Good quality machine– TGC sliders– Record images– High quality curvelinear probe

• Problems– Incorrect dates– Poor views– Fetal position

Routine

• History and consent from patient– Previous child with abnormality– Family history of abnormality– Exposure to teratogens eg drugs, infections– Explain limitations

• Growth scan

• Placental localisation

• Anatomy

Fetal head and face

• BPD and HC• Cerebellar view

– TCD = gestation– Foramen magna < 10mm– Nuchal fold < 6mm

• Lateral ventricles– Posterior aspect ventricle, Perpendicular to falx– <12mm normal, 12-15mm moderate, >15mm severe

• Orbits– Inner to inner border, 1/3 ratio of eyes and bridge of nose

• Lips and nose – Exclude cleft lip

• Profile– Micrognathia, proboscis

Fetal head and face

• BPD and HC• Cerebellar view

– TCD = gestation– Foramen magna < 10mm– Nuchal fold < 6mm

• Lateral ventricles– Posterior aspect ventricle, Perpendicular to falx– <12mm normal, 12-15mm moderate, >15mm severe

• Orbits– Inner to inner border, 1/3 ratio of eyes and bridge of nose

• Lips and nose – Exclude cleft lip

• Profile– Micrognathia, proboscis

Fetal trunk

• Coronal section– Heart, stomach, diaphragm

and bladder

• Sagittal section of anterior abdominal wall

• Kidneys– Coronal– Transverse

• Diaphragms sagittal view• Umbilical cord insertion• Two umbilical arteries

Fetal trunk

• Coronal section– Heart, stomach, diaphragm

and bladder

• Sagittal section of anterior abdominal wall

• Kidneys– Coronal– Transverse

• Diaphragms sagittal view• Umbilical cord insertion• Two umbilical arteries

Fetal heart

• Reduce gain• Situs• 4 Chamber view

– FHR and rhythm– Interventricular septum

• LVOT• RVOT• (Aortic arch)• (Ductal arch)

Fetal heart

• Situs• 4 Chamber view

– FHR and rhythm– Interventricular septum

• LVOT• RVOT• (Aortic arch)• (Ductal arch)

Fetal Spine and limbs

• Spine- reduce total gain• Sagittal with skinline in view• Coronal• Transverse- 3 ossification centres ‘tight’, not

splayed• Follow limb from trunk noting side• Full length all 12 bones• Exclude club foot• Feet- plantar view and count toes• Hands- open if possible and count fingers and

thumb

AND Coronal

OKAY!