Assessment of Limb Dominance and Trumpeter Posture in Children With Brachial Plexus Birth Injury

BACKGROUND: Children with brachial plexus birth injuries (BPBIs) may experience atypical posturing when performing activities of daily living, including eating. Clinical assessments often evaluate feeding ability through hand-to-mouth movements, using the unaffected arm as an internal control. This study examined differences between dominant and nondominant limbs and affected and unaffected BPBI limbs during feeding tasks and aimed to understand better the etiology of trumpeter posture in children with BPBI. METHODS: Joint angles were measured during feeding tasks using 3-dimensional motion capture in 23 typically developing children aged 6 to 18 years. Previously collected hand-to-mouth motion data from children with BPBI were used. Analyses compared dominant versus nondominant limbs within the control group and differences between the BPBI group and the control group. RESULTS: No differences were observed between dominant and nondominant limbs. In contrast, there were significant differences between the unaffected BPBI limb and the control group. The affected limb in the BPBI group differed from both the unaffected limb and the control group. The BPBI trumpeting group showed significantly decreased glenohumeral and humerothoracic external rotation and glenohumeral and humerothoracic cross-body adduction compared with the BPBI non-trumpeting group. Brachial plexus birth injury groups also showed significantly increased scapulothoracic internal rotation (scapular winging) compared with the BPBI unaffected and control groups. CONCLUSIONS: Symmetry was observed between dominant and nondominant limbs, but the unaffected BPBI limb differed from controls. Lack of external rotation was the primary factor in trumpeter posture, likely leading to compensatory movements affecting glenohumeral and humerothoracic joint motion. Glenohumeral and humerothoracic cross-body adduction may be secondary factors related to trumpeter posture.