What action can a patient perform to check for a lesion or injury at S1?

The action that can be performed to check for a lesion or injury at the S1 nerve root is the heel raise. The S1 nerve root is primarily responsible for controlling the muscles that allow for plantar flexion of the foot, specifically the gastrocnemius and soleus muscles. By performing a heel raise, where the patient stands on their toes, it directly assesses the functioning of these muscles and consequently the integrity of the S1 nerve root.

When a patient raises their heel off the ground, they activate the plantar flexor muscles. If there is a lesion or injury at the S1 level, the patient may experience weakness or inability to perform this action effectively. Thus, the heel raise is a crucial functional test for assessing the health of the S1 nerve root.

Walking on toes, raising the toes, or sitting on the ground do not specifically target the S1 nerve root function as effectively as the heel raise. They might evaluate other aspects of motor function or may involve different lower extremity nerve roots. Therefore, the heel raise stands out as the most relevant action in this context.