Final answer:
The expected response when a nurse dorsiflexes a patient's right ankle and strikes the tendon with a reflex hammer is plantar flexion of the right foot.
Step-by-step explanation:
When a nurse dorsiflexes a patient's right ankle 90 degrees and then uses a reflex hammer to strike the appropriate tendon, the expected deep tendon reflex is plantar flexion of the right foot. This reflex, also known as the ankle reflex, involves the gastrocnemius and soleus muscles and is commonly tested by striking the Achilles tendon. The response should be a quick contraction of these muscles, causing the foot to point downwards.