Ultrasound Imaging of Brachial and Antebrachial Fasciae

Abstract

Knowledge about fasciae has become increasingly relevant in connection to regional anesthesiology, given the growing interest in fascial plane, interfascial, and nerve blocks. Ultrasound (US) imaging, thanks to high definition, provides the possibility to visualize and measure their thickness. The purpose of this study was to measure and compare, by US imaging, the thickness of deep/muscular fasciae in different points of the arm and forearm. An observational study has been performed using US imaging to measure brachial and antebrachial fasciae thickness at anterior and posterior regions, respectively, of the arm and forearm at different levels with a new protocol in a sample of 25 healthy volunteers. Results of fascial thickness revealed statistically significant differences (p < 0.0001) in the brachial fascia between the anterior and the posterior regions; in terms of the antebrachial fascia, no statistically significant difference was present (p > 0.05) between the regions/levels. Moreover, regarding the posterior region/levels, the brachial fascia had a greater thickness (mean 0.81 ± 0.20 mm) than the antebrachial fascia (mean 0.71 ± 0.20 mm); regarding the anterior region/levels, the antebrachial fascia was thicker (mean 0.70 ± 0.2 mm) than the brachial fascia (mean 0.61 ± 0.11 mm). In addition, the intra-rater reliability reported good reliability (ICC2,k: 0.88). US imaging helps to improve grading of fascial dysfunction or disease by revealing subclinical lesions, clinically invisible fascial changes, and one of the US parameters to reliably evaluate is the thickness in the different regions and levels.

Ultrasound Imaging of the Superficial Fascia in the Upper Limb: Arm and Forearm

“…Using a high-resolution device (Sonosite Edge II, FUJIFILM, Inc. 21919, Bothell, WA, USA) with a 6–15 MHz linear transducer (HLF50x, Sonosite Edge II, FUJIFILM, Inc. 21919, WA, USA) and a screen resolution of 1680 × 1050 pixels, ultrasound images were taken of the arm and forearm with a specific protocol in accordance with Pirri et al [ 14 ]. A physician specialist in physical and rehabilitation medicine with 7 years’ experience in skeletal-muscle US imaging and US imaging of fasciae carried out the US measurements.…”

“…The US beam was kept perpendicular to the fascial layers because anisotropy artifacts typically affect them ( Figure 1 ). The power and overall gain of the US machine were adjusted to optimize visualization of the fascial layers and obtain the best scan possible [ 14 ]. The investigator used the short axis in according to Pirri et al [ 14 ].…”

“…The power and overall gain of the US machine were adjusted to optimize visualization of the fascial layers and obtain the best scan possible [ 14 ]. The investigator used the short axis in according to Pirri et al [ 14 ].…”

“…Notably, the ultrasound data collected for the same type of fascia are affected by the ultra-sonographer, the probe position, and/or intra-individual anatomical variability [ 14 ]. Consequently, it is mandatory, beforehand, to speak about fascial alterations or dysfunctions in pathological conditions to clearly know the normal aspect of the superficial fascia of the body, codifying the best probe position to visualize them inside the subcutaneous tissue.…”

“…Consequently, it is mandatory, beforehand, to speak about fascial alterations or dysfunctions in pathological conditions to clearly know the normal aspect of the superficial fascia of the body, codifying the best probe position to visualize them inside the subcutaneous tissue. While this knowledge is present for the deep/muscular fascia [ 11 , 14 , 15 ], to date, no study has evaluated the superficial fascia thickness of the arm and forearm measured by US imaging in the different regions and levels.…”