Fetal head/brain registry review

Question 1

Skull anatomy

Answer 1

8 cranial bones connected by sutures

Question 2

Foramen magnum

Answer 2

Opening at the base of cranium that allows passage of the spinal cord

Question 3

Cerebrum

Answer 3

-Two hemispheres divided by interhemispheric fissure
-Contains sulci and gyri
-Covered by 3 meninges layer

Question 4

Pia mater

Answer 4

Innermost meninges layer

Question 5

Arachnoid mater

Answer 5

Middle meninges layer

Question 6

Dura mater

Answer 6

Outer meninges layer

Question 7

Cavum septum pellucidum

Answer 7

Box shaped, midline brain structure seen between frontal horns of lateral ventricles
-Closes after 37 weeks
-Landmark for corpus callosum
*Does not communicate with the ventricular system

Question 8

Falx cerebri

Answer 8

Double fold of dura mater which separates the two brain hemispheres. Echogenic line

Question 9

Corpus callosum

Answer 9

Bridge between 2 brain hemispheres and provides communication between both sides

Question 10

Massa intermedia

Answer 10

Connects 2 lobes of thalamus together; 3rd ventricle travels within

Question 10

Thalamus

Answer 10

2 lobes of thalamus located on either side of falx, 2 lobes connected massa intermedia and 3rd ventricle travels within
*BPD/HC done at this level

Question 11

Ventricular system

Answer 11

Produce and transport cerebral spinal fluid to cushion the brain

Question 12

Choroid plexus

Answer 12

Located inside lateral ventricles and produce CSF

Question 13

CSF flow

Answer 13

Produced by choroid plexus in lateral ventricle, flows to 3rd ventricle via foramen of monro, 3rd ventricle connects/flows to 4th via aqueduct of sylvius (cerebral aqueduct), flows from 4th through foramina of luschka and foramen of magendie into cisterna magna then subarachnoid space

Question 14

Lateral ventricles

Answer 14

-Imaged superior to level of thalamus
-Choroid plexus should fill most of area
-Normal measurement of atrium <10mm
-Evaluate shape/size

Question 15

Posterior fossa

Answer 15

Level of cerebellum (length), cisterna magna, nuchal fold; orbits/mandible should not be seen

Question 16

Cerebellum

Answer 16

2 lobes that are joined by cerebellar vermis forming a dumbbell shape
-4th ventricle travels between both lobes but not normally seen
-Gestational weeks (20w=20mm)

Question 17

Cisterna magna

Answer 17

Posterior fossa of brain, largest cisterna in the head
-Normal 2-10mm

Question 18

Nuchal thickness/fold

Answer 18

Outer cranium to outer skin
-Normal <6mm

Question 19

Head anatomy seen at midline

Answer 19

-Falxes/fissures
-Cerebellar vermis
-Corpus collosum/CSP
-3rd/4th ventricle

Question 20

Head anatomy NOT seen at midline

Answer 20

-Lateral ventricles
-Thalamus
-Cerebellum
-Cerebrum

Question 21

Head biometry 14weeks+

Answer 21

Taken at level of thalamus, may include CSP, falx, 3rd and lateral ventricles
*most accurate for gestational age in 2nd trimester

Question 22

Biparietal diameter (BPD)

Answer 22

Leading edge to leading edge (outer to inner); ear to ear

Question 23

Head circumference (HC)

Answer 23

Outer circumference of cranium, NO scalp!

Question 24

Dolichocephaly

Answer 24

Flattened head
-Ratio of BPD/OFD < 0.75

Question 25

Mesocephaly

Answer 25

Normal head
-Ratio of BPD/OFD 0.75- 0.85

Question 26

Brachycephaly

Answer 26

Circular head
-Ratio of BPD/OFD > 0.85

Question 27

Cephalic index

Answer 27

Indicates head shape
Ratio of BPD/OFD (occipital frontal diameter)