The Major Challenges Facing Spinal Cord
The most common type of spinal cord injury is the result of concussive trauma, which accounts for approximately 35% of injured spinal cords. In this case, the spinal cord is not severed. Instead, an inpact leaves the soft tissue of the spinal cord bruised and damaged, leading to bleeding from local blood vessels and swelling of the cord inside the vertebra. Regardless of the type of spinal cord injury, however, a common set of events follows. Cells from the immune system infiltrate the area of primary injury, which expands for several days as local pathological processes continue in a cascade of secondary injury. The primary and secondary injuries cause the death of neurons and oligodendrocytes, resulting in the disruption of synaptic connections and the demyelination of axons. Demyelination of surviving intact axons greatly impairs action potential message conduction, and can render remaining connections useless. The neuronal communication highway is further disrupted because many axons are severed, cutting off the lines of communication between the brain and the muscles, and between the body sensory systems and the brain. By several weeks after the initial injury, the area of tissue damage has been cleared away by microglia from the CNS and macrophages from the immune system, and a fluid-filled cavity surrounded by a glial scar made up of astrocytes is left behind. Molecules that inhibit regrowth of severed axons are expressed at this site. This fluid-filled cavity, called a, now forms a barrier to the reconnection of the two sides of the damaged spinal cord.
While an injury to the spinal cord causes a complex array of damage, a surprising amount of the basic circuitry to control movement and process somatosensory information can remain intact. This is because the spinal cord is arranged in layers of circuitry. Many of the connections and neuronal cell bodies forming this circuitry above and below the site of injury survive the trauma. The goal of spinal cord injury research is to reconnect the wiring that controls muscle movement and provides sensory information to the brain. An important question in this regard is how much the surviving neurons know. In other words, given the opportunity, can neurons in the spinal cord regenerate and make not only new connections, but the correct connections ? As you can see that spinal cord injury is a serious matter, having a spinal injury claim can help you with the stress that over comes you. What ever the type of accident that may have caused this problem it is always best to be ready.
What Level of the Spinal Cord Connects to What ?
Just as sensory information is organized topographically into (with different regions of the skin projecting to different levels of the spinal cord), the spinal motor system is topographically organized as well. This is why injury to different levels of the spinal cord results in different levels of paralysis and/or loss of sensation.
No two injuries are identical. The diagram to the right illustrates the connections between the major skeletal muscle groups and each level of the spinal cord. A similar organization exists for the spinal control of the internal organs.