Objective: The aim of this study was to characterize the spectrum of neural injury patterns and secondary musculoskeletal abnormalities on magnetic resonance imaging (MRI) in children with obstetric brachial plexus palsy (OBPP).
Materials and
Methods: In this retrospective descriptive study, 56 children with OBPP who underwent brachial plexus MRI were included in the study. MRI examinations were reviewed for preganglionic and postganglionic abnormalities, distal plexus involvement, denervation-related muscle changes, and posterior humeral head subluxation. Patients were categorized as having pure preganglionic, pure postganglionic, or mixed injury patterns. Associations between muscle abnormalities, posterior humeral head subluxation, injury patterns, and patient age were evaluated using Chi-square, Fisher’s exact, and Mann–Whitney U-tests, as appropriate.

Results: The median age at MRI was 10.8 months. Pure preganglionic injury was identified in 15 patients (26.8%), pure postganglionic injury in 24 (42.9%), and mixed injury in 17 (30.4%). Overall, root involvement was most frequent at C6 (83.9%), followed by C7 (75.0%) and C5 (60.7%). Neuroma-like nodular thickening was observed in 16 patients (28.6%). Muscle atrophy was present in 44 patients (78.6%), muscle edema in 13 (23.2%), and posterior humeral head subluxation in 44 patients (78.6%). An association was observed between subscapularis muscle atrophy and posterior humeral head subluxation (84.1% vs. 50.0%, p=0.022). Patients with muscle edema were significantly younger than those without edema (p<0.001).

Conclusion: OBPP demonstrates a broad spectrum of neural and musculoskeletal abnormalities on MRI. In addition to characterizing preganglionic and postganglionic injury patterns, MRI provides valuable information regarding denervation-related muscle changes and secondary shoulder deformity, enabling comprehensive assessment of disease involvement.