What sensation change might accompany a herniated disc at the S1 root?

A herniated disc at the S1 nerve root can lead to specific neurological deficits due to its influence on local nerve function. One notable effect is the potential for a diminished or absent Achilles reflex. This reflex, also known as the ankle jerk reflex, is mediated by the S1 and S2 nerve roots. When there is compression or damage to the S1 root due to a herniated disc, the signal that triggers the reflex pathway can be disrupted. Consequently, a healthcare provider may observe a weakened or entirely absent response when assessing the reflex.

In this context, heightened sensations or sensory changes, such as increased reflexes in the arms or generalized sensory changes, are not typically associated with an S1 herniation, as those involve different nerve roots or regions. Therefore, recognizing the specific impact of the S1 nerve root on reflexive movements provides a clear understanding of the effects of a herniated disc at this level.