This chapter covers the general anatomy, development, and organization of the human spinal cord. It has 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal segments. It is formed by diverse neuronal populations (i.e., motor neurons, sensory neurons, spinothalamic neurons, interneurons), glial cells, and ascending and descending tracts that connect these cells with the brain and the rest of the body. The spinal cord is responsible for controlling the voluntary muscles of the limbs, trunk, viscera and blood vessels of the thorax, abdomen, and pelvis. Ascending and descending tracts are crossed at different levels, which allows a better understanding of spinal cord pathologies and syndromes.