While I think we all remember ‘roots, trunks, divisions, cords, and branches’ from medical school anatomy class, actually reading brachial plexus MRI – due to the complex anatomy and the complexity of the imaging sequences/appearances layered on top of it – is very difficult.

One of my ‘go-to’ articles for reading these cases is from RadioGraphics:

Demondion, X., Herbinet, P., Van Sint Jan, S., Boutry, N., Chantelot, C., & Cotten, A. (2006). Imaging assessment of thoracic outlet Syndrome. Radiographics, 26(6), 1735–1750. https://doi.org/10.1148/rg.266055079

It has wonderful anatomic dissection images as well as labeled CT and MRI images that help explain the complex anatomy of the brachial plexus and thoracic outlet. Definitely an aid when reading these often difficult cases. Below is one of the images from the article.

Figure 3c.  Assessment of the interscalene triangle with different imaging modalities. Sagittal gross anatomic section (a), computed tomographic (CT) image (b), T1-weighted magnetic resonance (MR) image (c), and sonogram (d) show the anterior scalene muscle (AS), clavicle (C), fifth cervical nerve root (C5), sixth cervical nerve root (C6), seventh cervical nerve root (C7), eighth cervical nerve root (C8), first rib (FR), middle and posterior scalene muscles (MS), subclavian artery (SA), subclavian vein (SV), and first thoracic nerve root (T1).