Novel approach of ultrasound-guided lateral recess block for a patient with lateral recess stenosis: A case report

Figure 4 Needle trajectory during lateral recess steroid injection. A: Ultrasound image of needle trajectory, the lateral recess (white triangle), articular process (cyan arrow), ligamentum flavum (white arrow), and intraspinal anterior complex (blue arrow), needle direction (yellow arrow), depth from the target injection point into the skin (yellow line); B: Diagrammatic explanation of the needle trajectory; C: Picture of the right place of probe position and needle insertion.