What is the expected appearance of the fetal spine on ultrasound?

• A. It should be straight throughout
• B. It should taper near the sacrum and widen near the base of the skull
• C. It should be curved throughout
• D. It should be irregularly shaped

Answer: (B)

The expected appearance of the fetal spine on ultrasound is characterized by a tapering near the sacrum and a widening near the base of the skull. This anatomical structure reflects the natural development and positioning of the spine during fetal growth. In the upper cervical region, the spine is broader and accommodates the brainstem and upper parts of the central nervous system, while in the lumbar and sacral regions, it narrows down, aligning with the shape and function of the lower vertebral components.

In addition, the tapered appearance in the lower portion is indicative of the developmental process, where the sacral spine allows for attachment to pelvis structures and aids in the overall biomechanics within the womb. Understanding this expected curvature is crucial for sonographers in order to assess normal fetal development and identify any potential anomalies that may arise in the spine or surrounding structures.