{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T12:26:00Z","timestamp":1787315160902,"version":"build-2736575974"},"reference-count":35,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T00:00:00Z","timestamp":1787270400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: Ultrasound-guided flexor pollicis longus (FPL) injection is limited by the muscle\u2019s deep location and its proximity to the cephalic vein (CV) and superficial branch of the radial nerve (SBRN). We aimed to identify the wrist and forearm posture producing the largest measured corridor width and target exposure. Methods: This prospective single-center study evaluated 51 forearms from 27 healthy adult volunteers with full range of motion, using transverse ultrasound of the distal volar forearm in six standardized positions. Two corridors were measured: CV-to-SBRN (L1, Approach A) and CV-to-radial-cortex apex (L2, Approach B), with FPL exposure height (F). Results: L2 was present in all limbs and was wider with forearm supination than in neutral (supination [SUP], +2.36 mm; flexion plus supination [F+SUP], +2.05 mm; extension plus supination [E+SUP], +2.66 mm; each p &lt; 0.001), an ~40% increase; the three supination postures did not differ. F increased across the same postures and was greatest in E+SUP (+2.32 mm), which did not differ from SUP. L1 was absent in 12\u201328% of limbs and, where present, was narrower with supination (both p &lt; 0.001). Conclusions: In healthy adults, forearm supination widened the safety corridor and increased target exposure. Applicability to spasticity requires confirmation.<\/jats:p>","DOI":"10.3390\/diagnostics16162674","type":"journal-article","created":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T11:37:34Z","timestamp":1787312254000},"page":"2674","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Forearm Supination Increases the Safety Corridor and Target Exposure for Ultrasound-Guided Flexor Pollicis Longus Injection: A Prospective Study in Healthy Adults"],"prefix":"10.3390","volume":"16","author":[{"given":"Hoon Ki","family":"Song","sequence":"first","affiliation":[{"name":"Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center, Seoul 05368, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hyo Jung","family":"Kang","sequence":"additional","affiliation":[{"name":"Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center, Seoul 05368, Republic of Korea"},{"name":"Department of Medicine, Graduate School, Korea University, Seoul 02841, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Woo-Hwa","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center, Seoul 05368, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ho-Yong","family":"Jeong","sequence":"additional","affiliation":[{"name":"Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center, Seoul 05368, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chi Hwan","family":"An","sequence":"additional","affiliation":[{"name":"Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center, Seoul 05368, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hyokyum","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center, Seoul 05368, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"354906","DOI":"10.1155\/2014\/354906","article-title":"Pathophysiology of spasticity: Implications for neurorehabilitation","volume":"2014","author":"Trompetto","year":"2014","journal-title":"BioMed Res. 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