Review of the dimensions of the median nerve and carpal tunnel using sonography in asymptomatic adults

Abstract

The normal range at two SDs of the CSA of the median nerve at the inlet was 5.2-9.6 mm(2) . The upper limit of volar bowing of the flexor retinaculum was 0.8 mm. The FR overlaps with values obtained in other studies of patients with carpal tunnel syndrome. The mean AP diameter of the CT was 10.4 mm (SD 1.1). To the best of our knowledge, this is the largest study performed in an asymptomatic population assessing the different sonological parameters related to the CT.

Idiopathic Carpal Tunnel Syndrome: Evaluation of the Depth of the Carpal Tunnel by Ultrasonography

“…With respect to handedness and sex, our results agree with those of Mani et al (2011), but we should also take in consideration that their study did not include patients. Also, regarding the relation of DCT with body mass index, our results are in agreement with those of Hleb s et al (2014), and as for DCT and age, our results agree with those of Pierre-Jerome et al (1997).…”

“…The small difference between the two studies may be explained by the difference in ethnicity between the two groups and also by the use of cadavers in the study by Pacek et al (2010). Another study obtained a mean DCT of 1.4 cm in an asymptomatic population, but had not performed electrophysiologic studies confirm that those volunteers did not have CTS; this also could explain the difference between the two studies (Mani et al 2011). It appears counterintuitive to find that DCT is greater in diseased than in healthy individuals; however, even if the cause of CTS is a small canal, the increased pressure inside the canal results in an increase in canal dimensions.…”

“…Measurements were made at this point to ensure accuracy. Mani et al (2011) used the same level to measure DCT. To make a logical comparison, CSA and FR were measured at the same level.…”

“…Evaluation of the dimensions of the carpal tunnel has been inadequately addressed in the literature on CTS, as most previous studies evaluated the dimensions of the carpal tunnel in normal individuals and not in CTS patients. These studies, which were performed on healthy patients or cadavers, employed either computed tomography (CT) or magnetic resonance imaging (MRI), or used a silicon cast to fill the carpal tunnel to measure these dimensions (Bower et al 2006;Mani et al 2011;Pacek et al 2010;Widgerow et al 1996).…”

Differentiation between nerve and adipose tissue using wide-band (350-1,830 nm) in vivo diffuse reflectance spectroscopy

“…Dashed lines in the corresponding colors indicate the respective standard deviations. Median nerve diameter is on average 6 mm at the measurement site (i.e., at distal fore-arm [40]). purposes and on additional carpal tunnel release surgery data for test purposes.…”