Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2026 Aug 11;14:1857511. doi: 10.3389/fped.2026.1857511

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2026 Xie, Sui, Zhang, Zhang, Li, Sun and Liu.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

PMC Copyright notice

Ultrasound images of the lumbar spine are shown in three panels labeled A, B, and C, each displaying different lumbar vertebrae levels marked with annotations, arrows, and stars indicating anatomical structures for reference. — Pre-procedural spinal ultrasound for planning repeated intrathecal access. (A) Mid-sagittal sonographic view of the lumbar spine showing the vertebral levels (L1–L3). Within the spinal canal, the hypoechoic spinal cord (open arrow) contains the central echo complex (arrow), while the conus medullaris is identified distally (arrowhead). Caudal to the conus, the filum terminale (thin arrow) is visualized within the dural sac and is surrounded by the echogenic cauda equina nerve roots. This view allows identification of the caudal end of the spinal cord and helps avoid selection of an excessively high puncture level. (B) Axial sonographic view at the interlaminar level demonstrating the subarachnoid space (asterisks) and the intrathecal nerve roots. This view helps confirm midline spinal canal anatomy and the feasibility of safe intrathecal access. (C) Lower lumbar sagittal view showing the selected puncture level (L3–S1), the subarachnoid space (asterisk), and the filum terminale (thin arrow). The dotted line indicates measurement of the skin-to-dura distance, which was used to estimate the expected needle insertion depth and optimize the puncture trajectory.