How do abnormalities of the spinal cord nerves or muscles contribute to arthrogryposis?

In the context of arthrogryposis multiplex congenita, abnormalities of the spinal cord, nerves, or muscles are considered the primary intrinsic causes of the condition.1

These neurological and muscular dysfunctions lead to arthrogryposis through the resulting muscle weakness. When muscles are weak or fail to function properly during fetal development, they cannot provide the necessary movement or support for the joints. This lack of movement and muscle-driven activity causes the joints to become fixed or contracted, resulting in the characteristic deformities seen at birth, such as clawed fingers and contracted limbs.12

While some joint deformities can be caused by extrinsic factors like amniotic fluid deficiency, the majority of arthrogryposis cases are attributed to these intrinsic problems, where the underlying spinal cord or muscular pathology prevents normal joint development and mobility.12