Proximal Extension of the Flexor Retinaculum: A Cadaveric Study (pp. 267-274)
Authors: (Thisara Weerasuriya, Surangi Yasawardene, Narendra Pinto, Tameside General Hospital, UK, and others)
Abstract: Introduction: It has been noted in the literature that recurrence of carpel tunnel syndrome is approximately 10%. MRI scans on these recurrent cases have demonstrated an extension of the flexor retinaculum more proximally into the forearm than the traditionally taught extent. This accounting for inadequate decompression of the median nerve resulting in either persistence of symptoms or recurrence of the symptoms.
The purpose of this cadaveric study was to demonstrate an anatomical extension of the flexor retinaculum beyond the demarcation traditionally taught, if present.
Methods: The aim of our study was to determine the extent of the carpel tunnel in cadavers impregnated with formaldehyde by dissection. The dissections were carried out by the first author in the institution where cadaveric dissections are a major teaching tool for medical students. The cadavers were of an Asian population. In cadavers where an extension of the retinaculum were found beyond the normal anatomical demarcation traditionally taught, the senior author was involved in verifying the extent of the retinaculum.
A calliper was used to measure the length of the retinaculum and the thickness of the retinaculum at three points. The thickness of the distal most point, the thickness of the midpoint and the thickness of the proximal most point were noted.
A total of 26 cadavers were dissected over a period of a year. Both hands were dissected in each of these cadavers. As a result of this a total of 52 wrists were dissected.
Results: The length of the retinaculum had a range of 36mm-83.5mm with an average length of 42.3mm.
Five wrists had extension of the retinaculum beyond the traditional demarcation.