Alterations in the relationships between the balanced extrinsic and intrinsic musculature of the hand due to trauma or secondary to the effects of systemic disease may cause the development of functional deformities such as a boutonnière or swan-neck deformity. Swan-neck deformity Boutonniere deformity Deformity PIPJ Hyperextension PIPJ Flexion DIPJ Flexion … Continue reading Swan neck deformity vs Boutonniere deformity