Cervical spine
The spinal nerves, which originate from the spinal cord segment at the level of the seventh cervical vertebra (C7), are involved in the formation of a nerve plexus known as the brachial plexus. From this plexus emerge sensory and motor nerve fibers for the arms, shoulders and chest. A herniated disc at this height of the spinal cord thus causes muscle weakness in muscle groups of these body regions.
The triceps brachialis muscle is particularly affected, which can be checked by means of the triceps tendon reflex. If it is abolished or at least severely weakened, this indicates a disc prolapse at the level of C7. Furthermore, root damage at C7 leads to pain on the back shoulder, which can extend over the outside of the forearm to the index and middle finger.
In these areas, sensory disturbances such as tingling or numbness can also occur. The most common cause of nerve root irritation here, as in other spinal cord sections, is a herniated disc. The complaints caused by it increase mainly depending on the load. In case of nerve root irritation caused by a tumor, the symptoms would instead increase at rest.
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