For your powerpoint on neuro-ortho overlap, you discuss that below the c-spine, the spinal nerve is named for the vertebra ABOVE. So at L5/S1, I would assume that the L5 spinal nerve exits at this level… However, when you give an example of common disc herniations, you say that a disc herniation at L5/S1 would lead to S1 impairments (PF weakness, dec sensation at posterior and lateral LE). Can you explain this? Am I misunderstanding?
Thank you for this question! As an NCS, orthopedics is not my specialty, so I had to do some digging to confirm. The website below does a nice job of explaining the difference between “exiting” and “traversing” nerve roots at each spinal level. At the L5-S1 level, the L5 nerve root is exiting the spinal column while the S1 nerve root is crossing the disc to exit at the next level below. In the lumbar spine, disc herniations tend to affect the traversing nerve root due to the most common direction of herniations (posterolateral). In the cervical spine, disc herniations usually affect the exiting nerve root (lateral herniations).