The nerve roots comprising cauda equina should lie in the dependent portion of the thecal sac.
– Should see gentle oscillating movements with the baby’s cardiac pulsations and respiration.
– Symmetry. Look for asymmetry indicative of pathology (space occupying mass or unilateral abnormality)
– Particular attention should be paid to the integrity the posterior neural arches in the transverse plane.
– Check the vertebral bodies for alignment, shape and symmetry in both transverse and sagittal planes.
– If there is a dimple or skin defect, this should be carefully examined with a high frequency probe to look for a skin – thecal sac fistula.
– Use minimal pressure so as not to compress and thus obscure a fistula tract.
– An anatomical variant is a thin hypoechoic fibrous band from the dimple to the coccyx. This is of no clinical signifigance. Most true fitsulae will be higher than the coccygeal region.
– If CSF is leaking, an MRI should be performed.