Spinal Cord
Spinal cord is a nerve sheath belonging to the central nervous system and is mainly responsible for control of the most viscera and blood vessels of the thorax, abdomen and pelvis. The meninges of spinal cord including dura mater, arachnoid, and pia mater lie within the vertebral column. In humans, an average male has about 45 cm long spinal cord, whereas a female has about 42-43 cm long spinal cord. The superior end of the cord is connected to the base of the brain at the brain stem. The bottom or inferior end is found about two third of the way down the backbone.
Spinal cord has two spindle shaped enlargements; (a) cervical enlargement, and (b) lumbar enlargement. Human spinal cord has 31 pairs of spinal nerves, and each nerve pair is connected to one body segment. However, the spinal cord itself has no segments. These spinal nerves pairs are subdivided into five categories depending on the location where they emerge through the vertebral column. They are cervical nerves (8 pairs), thoracic nerves (12 pairs), lumbar nerves (05 pairs), sacral nerves (05 pairs), and coccygeal nerves (one pair).
Backbone
Backbone, also called vertebral column or spinal column, is unique to vertebrates. It is the main part of the skeletal system that provides support to body. In addition to the supporting function, the backbone protects the spinal cord, which lies inside the backbone. The superior end of backbone is connected to skull, whereas the bottom links up with the pelvis. This bony part is not a single bone, but is made up of 33 separate bones (in humans) called vertebrae. The human backbone has four curvatures, namely cervical, thoracic, lumbar and sacral. These curves are responsible for providing of flexibility and support for the spinal cord.
What is the difference between Spinal Cord and Backbone?
• Spinal cord belongs to the nervous system, whereas backbone belongs to the skeletal system.
• Spinal cord is a long nerve sheath, whereas backbone is composed of vertebrae. Thus, backbone is segmented, unlike the spinal cord.
• Spinal cord lies inside the backbone.
• In an average human, backbone is longer than spinal cord.
• Backbone provides support for body and protects the spinal cord, whereas spinal cord controls the visceral activities throughout the body.