Spinal Cord Anatomy CLOSE

Dorsal Rootlet Entry

Dorsal rootlet entry into the spinal cord is shown diagrammatically on the left and realistically on the right. Top Left: Each unipolar primary afferent neuron has its cell body in a spinal ganglion. The central axon enters the dorsolateral sulcus and divides into cranial and caudal branches. Both branches give off collateral branches that enter the gray matter to synapse on spinal neurons. In the case of larger fibers (touch & kinesthesia), the cranial branch ascends in fasciculus gracilis or fasciculus cuneatus. Bottom Left: Transverse view showing that cranial and caudal branches of thin fibers (pain & temperature) collect in the dorsolateral fasciculus; while thick branches accumulate medially. Right: Dorsal view of a rootlet. Notice that fibers divide into cranial and caudal branches which give rise to collateral branches that synapse on spinal neurons.

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