A 2830 g full-term baby, born by breech delivery, exhibited weak crying and sucking and severe hypotonia of the extremities after birth. Magnetic resonance imaging (MRI) showed marked thinning of the cervical cord at the level of C4 and C5. This lesion evolved into focal syringomyelia by the fourth month after birth. In this patient, MRI was useful in detecting the initial spinal cord injury, which appeared as marked thinning, and the subsequent syringomyelia as well. The role of birth trauma in cervical spinal cord injuries is discussed.