anatomic & sonographic appearance of fetal spine & neck Flashcards
what term describes what begins during the early part of the 4th week (22-23 days) in the region of the 4th to 6th pairs of somites &
• Fusion of the neural folds proceed in cranial and caudal directions until only small areas remain open at both ends
with regards to spine development?
neurulation
what is a neural tube?
• Differentiates into the
central nervous system,
consisting of spinal cord
& brain
what is the lumen of the neural tube that until closure
communicates with the amniotic cavity
& later becomes the ventricular system of the brain & the
central canal of the spina cord
nerual canal
What gives rise to cells that form most of the
peripheral and autonomic nervous systems, spinal, cranial & autonomic ganglia
neural crest
what can you see at 17 days (A)
*note any changes b/t A & B (21 days post conception)
A - trlaminar disk
B - 21 days post conception
C- 28 days post conception. The hallow red ovoid structure is the neural fold that evolved into a closed neural tube
when and where and how does ossification begin (spinal development)?
Begins in the lower thoracic fetal spine at approx. 10 weeks gestational age
– The centra ossifies in both cranial and caudal directions
simultaneously
A is 11 weeks + 4 days B is 13 weeks C is 15 weeks +2
days menstrual age
what plane are these images taken from?
anteroposterior (AP), lateral
*14 weeks gestation
when does US eval for spina bifida occur?
why?
b/t 16 & 22 weeks gestation
confirm neural tube closure, detect masses
protocol
Document
• A transverse & longitudinal or coronal at each level
– Cervical spine (c-spine)
– Thoracic spine (t-spine)
– Lumbar spine (l-spine)
– Sacrum
• Do all spine images together if possible for continuity
what plane is the Best way to visualize all 3 ossifications
as well as the posterior skin line
tranverse
what plane Will show the centra & one of the lateral
neural processes
longitudinal
what plane Will show
– Only the two lateral neural processes (if beam is slightly posterior)
– Two lateral neural processes with a couple of centra in between (if beam is slightly anterior)
coronal
how to you place your Td When the spine is placed directly under the ultrasound beam
Position the transducer so the beam
goes through the spine
what is important to note about these trans images?
skin thickness covering the posterior laminae
what might abnormal shapes of 3 ossifications in transverse indicate?
what can lack of ossificaton in early 2nd tri be mistaken for?
splayed pedicles moved away from midline w/ increased distance b/t pedicles
abnormal splaying (see below)
what plane?
sagittal
what is the difference between these 2 coronal images?
top is Slightly more posterior without centrum
bottom is Slightly more anterior with centrum (arrows)
what is this?
cervical spine
what is this?
thoracic spine
what is this?
lumbar/sacral spine
what is this?
thoracic/lumbar spine
what is this?
spine
what is this?
sacral spine
what is this?
transverse spine
27 weeks
27 weeks
what position is the fetus in?
breech
what position is this fetus in?
transverse
