Spinal cord: Cross section (Internal morphology) (English)

The gray matter of the spinal cord is a butterfly shaped structure which is functionally divided into anterior, posterior and lateral horns. At the center of the spinal cord is a canal filled with cerebrospinal fluid known as the central canal. The central canal runs longitudinally through the entire length of the spinal cord and represents the most caudal portion of the ventricular system. The gray matter which surrounds the central canal is composed of the anterior and posterior gray commissures that bridge the anterior and posterior horns of each half of the spinal cord. The white matter of the spinal cord occupies the space around the gray matter and is divided into anterior, posterior and lateral funiculi. The cervical and upper thoracic (C1-T6) posterior funiculi are further subdivided into a medial gracile fasciculus and a lateral cuneate fasciculus. Tracts of the gracile fasciculus are responsible for transmitting conscious proprioception, fine touch and vibration from the lower half of the body, while tracts of the cuneate fasciculus transmit these sensations from the upper half of the body. Running between the two halves of the spinal cord are the anterior and posterior white commissures.