Hi. I'm Dr. John Shim, and through my online video's, I am sharing how I view
situations as a spine surgeon. Before we can go to any specific detail, I think it's
important that you understand some basic spine anatomy. As physicians, and
scientists, we study the spine for years. To understand some of the concerns,
it is very helpful to understand some basic spine anatomy. The spine is a protective
scaffolding, that allows the nerve tissues to safely extend from the brain
to the limbs and a torso of the body. These nerve tissues are the spinal cord,
and the individual nerves that extend from the spinal cord. The spinal cord, and
nerves float inside a tough water filled sac called the dural tube. The dural tube
is located within the center of this protective spinal bones. Because the
spinal cord and nerves float within this water tube, it has protection from
some of the twisting and jarring motions experienced by your body. Because of the
need for motion, the spine must not only be protected, but must allow movement.
The hard nerve encasing bones are connected to ligaments, and tendons. Attached
muscles allow coordination of movement. The hard front of the spine bone, called
a vertebral body, is sandwiched between large shock absorbers called
intervertebral discs. These discs allow motion, and also provide shock
absorption. The discs are composed of two main components. The inner soft core is
called the nucleus pulposus. It is full of water, and absorbs the forces placed
on the large flat vertebral body bones. The outer part of the disc is called the
annulus. It is a tough woven cartilage structure that holds the nucleus in
place, as well as acts as a ligament that holds that attaches the vertebral bodies
together. The intervertebral discs also provides a
transition between the boney vertebra, and allows a space and a boney opening for individual nerves
to escape from the spine, and travel to it's respective body areas. This hole, or
foramen, is an opening between the bone and the disc interface. This spine
sandwich the vertebral body, disc, and vertebral body is called the functional
spine unit. There is motion initiated by contraction of the attached muscles and
tendons. Because of the elastic nature of the vertebral disc,
there is also flexion. extension and rotation of the disc. The rear or
posteriorly located joints that connect the vertebral together are called the
facet joints. Those joints are lined with smooth cartilage, and is designed to move
smoothly within a certain arch of movement. As you can see, even the most
simplified overview of the functional spine unit anatomy is complex.
To further understand how the spine works, the body also needs a
way to register and measure how much each ligament, muscle or tendon stretches.
These measurements provide feedback, and allow smooth coordination. This means
there are small nerves that measure compression, tension, and stretch. These
nerves are placed on the various parts of the functional spine unit, and can also
signal injury, or register pain. Because of the complexity of the spine, and the
natural wear that happens to all our body parts, maybe you can see how the
discs can wear out, that ligaments can stretch, and the nerves can get pinched. I hope
this video is helpful for your understanding of the spine. Thank You!