The volar antebrachial fascia represents a thickening of the volar forearm fascia as it approaches the carpal tunnel. Proximally, it is continuous with the forearm fascia, and distally it blends with the proximal TCL complex. I define the carpal tunnel inlet as the region beneath the antebrachial fascia and proximal TCL complex. This area is often overlooked as a clinically important site of MN compression in CTS.
Careful evaluation of the carpal tunnel inlet is important when assessing CTS sonographically. Beginning the examination in the distal forearm region and systematically scanning through the antebrachial fascia and proximal TCL complex frequently reveals important findings of MN compression that may be overlooked if imaging begins more distally within the tunnel. Both short and long-axis transducer orientations provide complementary information regarding nerve size, echotexture, and focal compression, allowing for a more complete assessment of CTS pathology.
Excellent video and explanation!
Before my use of US as an orthopedic hand surgeon, I utilized an endoscopic carpal tunnel release technique for patients. After releasing the proper TCL I would routinely also release more of the distal forearm antebrachial fascia proximally through the same incision with blunt tenotomy scissors to ensure the nerve was extensively decompressed.
Since moving to use of US both from a diagnostic standpoint and percutaneous US-guided release technique, I have most commonly found the median nerve to be largest at the level of the lunate peak and therefore release the TCL and antebrachial fascia up to the lunate peak. If I were to find the nerve with US evidence of more proximal compression as well I would adjust my incision proximally or reinsert the US release device proximally as well to obtain a further decompression of the median nerve.
Excellent video- thx for sharing.