The underlying cause of arthrogryposis is fetal akinesia. Fetal abnormalities—such as neurogenia, muscular or connective tissue disorders, limitations to mechanical movement—or maternal disorders—such as infections, substance abuse, trauma, or maternal illness—may be the cause of fetal akinesia. Fetal akinesia results in development of excess connective tissue around the joint. The joint becomes fixed and the limited movement within the uterus further exacerbates the joint contracture.

Arthrogryposis. A, Two sisters with the generalized form of the disorder. Note the stiff posture and tubular appearance of the limbs. Motion of all joints is limited as a result of failure in the development of or degeneration of muscular structures. Their stature is short. B, The lateral view highlights the flexion of contractures of the elbows.