Median nerve flattening ratio
Citation, DOI, disclosures and article data
Citation:
Weerakkody Y, Bell D, Median nerve flattening ratio. Reference article, Radiopaedia.org (Accessed on 21 Mar 2025) https://doi.org/10.53347/rID-166926
rID:
166926
Article created:
Disclosures:
At the time the article was created Yuranga Weerakkody had no financial relationships to ineligible companies to disclose.
View Yuranga Weerakkody's current disclosures
Last revised:
Disclosures:
At the time the article was last revised Daniel J Bell had no financial relationships to ineligible companies to disclose.
View Daniel J Bell's current disclosures
Revisions:
2 times, by
2 contributors -
see full revision history and disclosures
Systems:
Synonyms:
- Flattening ratio - median nerve
- Median nerve flattening ratio (FR)
The median nerve flattening ratio is a parameter used for the diagnosis of carpal tunnel syndrome (usually by ultrasound). It is calculated by dividing the span of the long axis by that of the short axis of the median nerve at around the pisiform level.
A ratio of greater then 3 is often considered supportive of the diagnosis of carpal tunnel syndrome.
References
- 1. Chang Y, Hsieh T, Tzeng I, Chiu V, Huang P, Horng Y. Ratio and Difference of the Cross-Sectional Area of Median Nerve to Ulnar Nerve in Diagnosing Carpal Tunnel Syndrome: A Case Control Study. BMC Med Imaging. 2019;19(1):52. doi:10.1186/s12880-019-0351-3 - Pubmed
- 2. Linehan C, Childs J, Quinton A, Aziz A. Ultrasound Parameters to Identify and Diagnose Carpal Tunnel Syndrome. A Review of the Literature. Australasian Journal of Ultrasound in Medicine. 2020;23(3):194-206. doi:10.1002/ajum.12219 - Pubmed
- 3. Kanagasabai K. Ultrasound of Median Nerve in the Diagnosis of Carpal Tunnel Syndrome—Correlation with Electrophysiological Studies. Indian J Radiol Imaging. 2022;32(01):016-29. doi:10.1055/s-0041-1741088 - Pubmed
- 4. Zhang L, Rehemutula A, Peng F, Yu C, Wang T, Chen L. Does the Ratio of the Carpal Tunnel Inlet and Outlet Cross-Sectional Areas in the Median Nerve Reflect Carpal Tunnel Syndrome Severity? Neural Regen Res. 2015;10(7):1172-6. doi:10.4103/1673-5374.160117 - Pubmed
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