Brachial plexus post-ganglionic root avulsion
54yo male post trauma. Fracture inferior angle right scapula and right upper limb weakness.
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The roots of the brachial plexus are abnormal. The C5, C6 and C7 nerve roots are thickened, wavey and hyperintense, and the dorsal ganglia appears displaced externally, with suggestion of pseudomeningocoele formation at the C6-7 foramen. The cervical spinal cord is normal, and the rootlets appear preserved. Denervation oedema with moderate atrophy of the rotator cuff muscles present. Fracture through the inferior angle of the right scapula. Prominence of the left C7 dorsal root ganglia may be related to injury. Anterior C6-C7 fusion noted.
Likely ganglion/post ganglionic avulsion of the C5 to C7 nerve roots.
Postganglionic lesions of the brachial plexus occur distal to the dorsal root ganglion and can be managed with nerve grafting to provide a better prognosis. MRI features of post-ganglionic lesions include 1,2:
- Hypo to isointense appearance of the affected nerve on T1-weighted imaging, hyperintense on T2-weighted imaging
- Nerve fibres appear in discontinuity and distal nerve contraction ball visible if avulsion injury
- Can have direct compression of involvement of nerves by haematoma, fracture fragment, exuberant callus secondary to fracture
Case courtesy of A/Prof Pramit Phal.
- 1. Sureka J, Cherian RA, Alexander M et-al. MRI of brachial plexopathies. Clin Radiol. 2009;64 (2): 208-18. doi:10.1016/j.crad.2008.08.011 - Pubmed citation
- 2. Lawande M, Patkar DP, Pungavkar S. Pictorial essay: Role of magnetic resonance imaging in evaluation of brachial plexus pathologies. Indian J Radiol Imaging. 2012;22 (4): 344-9. doi:10.4103/0971-3026.111489 - Free text at pubmed - Pubmed citation