Anatomy of the Brachial Plexus

Correlation Between Ultrasound Imaging, Cross-Sectional Anatomy, and Histology of the Brachial Plexus

“…The angles between the brachial plexus nerve roots and the axis of the spinal cord gradually decrease; that is, the nerve exits at C5 sharply caudal, whereas the angle at T1 is almost straight. 4,5 Optimal ultrasound imaging of individual nerve roots is provided only when the probe angle is varied, perpendicular to each nerve root axis. Thus, it is almost impossible to clearly capture all nerve roots in 1 image using 1 angle of the probe.…”

“…The ultrasound probe position at 5 anatomic locations along the course of the brachial plexus was described by Perlas et al 23 : an axial oblique plane for the interscalene location (1), a coronal oblique plane for the supraclavicular location (2), a parasagittal plane for the infraclavicular location (3), and transverse planes for the axillary (4), midhumeral, and more distal locations (5). Pressure, alignment, and rotating and tilting with the ultrasound transducer are necessary to maximize reflection at nerve-tissue interfaces to optimize image quality.…”

The Ultrasound Images of the Proximal Interscalene Space

“…The evidence, in fact, shows the spinal nerve is monofascicular. 3 Moreover, the monofascicular structure of C6 and the bifascicular nature of the plexus root at the same level are readily apparent in our Figure 2, panels A and B.…”

Ultrasound-Guided Interscalene Nerve Block: An Alternative Technique to Anatomical Landmark-Guided Approaches

“…Although the onset of complete block was not significantly different between the two groups, there was a slight delay in onset of complete block, particularly, in patients with surface landmark approach. This finding may have been because of the nonhomogenous distribution of motor, sensory, and connective tissue in nerve roots [13,14], such that a needle may have been proximate to one fiber type whereas at some distance from another type [15].…”