Posterior view of spinal cord at level of foramen magnum. The occipital bone and most of the atlas have been removed to expose the inferior surface of the cerebellum and cerebellar tonsils, the proximal spinal cord, and the vertebral arteries ascending into the posterior cranial fossa. The posterior or dorsal white columns of the spinal cord convey fine touch, 2-point discrimination, conscious proprioception, and vibration sensations from the skin and joints of the body (except the head). Lateral to these, the C2 dorsal rootlets enter the posterolateral sulci (dorsal root entry zone) of the C2 segment of the spinal cord. The neuronal cell bodies of these sensory axons are located in the C2 dorsal root (or spinal) ganglion. The dorsal root unites with the anterior or ventral root (conveying motor axons) to form the very short C2 spinal nerve, which quickly divides into an anterior ramus and posterior ramus. The spinal accessory nerves form from rootlets emerging from the lateral surface of the C1-C5 segments of the cord. They ascend between the anterior and posterior roots and enter the posterior fossa through the foramen magnum. (Image courtesy of AL Rhoton, Jr.)