Notice the cervical and lumbar enlargements. The enlargement in the cervical part of the spinal cord is due to the many axons that are necessary to control the muscles of the wings. The lumbar enlargement is due to many axons that control the limbs. Also notice the thin thoracic section of the spinal cord. This is because movement of the wings and limbs do NOT need to be coordinated. When birds fly, their legs are tucked under their bodies.

[Back to Spinal Cord Comparisons]