However, even among medical educators who use this approach, many are not aware of the neuropsychiatric phenomenon they are using, known as pareidolia. We will describe pareidolia (a form of patternicity) and give two examples of its use in the clinical teaching of musculoskeletal imaging abnormalities: the winking owl and the Scottie dog.

Objective To determine the relationship between sacroiliac joint (SIJ) contrast dispersal patterns during SIJ corticosteroid injection and pain relief at 2 and 8 weeks after the procedure. The association between the number of positive provocative SIJ physical examination maneuvers (minimum of one in all patients undergoing SIJ injection) and the patient’s response to the intervention was also assessed. Design Retrospective chart review. Setting Academic outpatient musculoskeletal practice. Patients Fifty-four subjects who underwent therapeutic SIJ corticosteroid injection were screened for inclusion; 49 subjects were included in the final analysis. Methods A retrospective review of electronic medical records identified patients who underwent SIJ corticosteroid injection. Fluoroscopic contrast flow patterns were categorized as type I (intra-articular injection with cephalad extension within the SIJ) or type II (intra-articular injection with poor cephalad extension). Self-reported numeric pain rating scale (NPRS) values at the time of injection and 2 and 8 weeks after the procedure were recorded. The number of positive provocative SIJ physical examination maneuvers at the time of the initial evaluation was also recorded. Main Outcome Measures The primary outcome measure was the effect of contrast patterns (type I or type II) on change in NPRS values at 2 weeks and 8 weeks after the injection. The secondary outcome measure was the association between the number of positive provocative SIJ physical examination maneuvers and decrease in the level of pain after the procedure. Results At 2 weeks after the procedure, type I subjects demonstrated a significantly lower mean NPRS value compared with type II subjects (2.8 ± 1.4 versus 3.8 ± 1.6, respectively, P =.02). No statistically significant difference was observed at 8 weeks after the procedure. NPRS values were significantly reduced both at 2 weeks and 8 weeks, compared with baseline, in both subjects identified as having type I flow and those with type II flow (P < .0001 for all within-group comparisons). Conclusions Fluoroscopically guided corticosteroid injections into the SIJ joint are effective in decreasing NPRS values in patients with SIJ-mediated pain. Delivery of corticosteroid to the superior portion of the SIJ leads to a greater reduction in pain at 2 weeks, but not at 8 weeks. Patients with at least one positive provocative maneuver should benefit from an intra-articular corticosteroid injection.

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A new technique for performing nerve blocks of the ganglion impar (ganglion Walther) is presented. These injections have been reported to relieve coccydynia (tailbone pain), as well as other malignant and nonmalignant pelvic pain syndromes. A variety of techniques have been previously described for blocking this sympathetic nerve ganglion, which is located in the retrorectal space just anterior to the upper coccygeal segments. Prior techniques have included approaches through the anococcygeal ligament, through the sacrococcygeal joint, and through intracoccygeal joint spaces. This article presents a new, paracoccygeal approach whereby the needle is inserted alongside the coccyx and the needle is guided through three discrete steps with a rotating or corkscrew trajectory. Compared with some of the previously published techniques, this paracoccygeal corkscrew approach has multiple potential benefits, including ease of fluoroscopic guidance using the lateral view, ability to easily use a stylet for the spinal needle, and use of a shorter, thinner needle. While no single technique works best for all patients and each technique has potential advantages and disadvantages, this new technique adds to the available options.