Final answer:
Spinal anesthesia causes loss of A-delta and A-alpha nerve fibers, which can be assessed through sensory and motor function tests.
Step-by-step explanation:
The first nerve fibers to be lost by spinal anesthesia are the small-diameter, thinly myelinated fibers known as A-delta fibers, followed by the larger-diameter, myelinated A-alpha fibers. These fibers are responsible for transmitting sensory information, including pain and temperature, as well as motor control signals.
These nerve fibers can be assessed by evaluating sensory and motor function. Sensory function can be assessed through various tests, such as pinprick sensation or temperature discrimination, to determine if there is any loss or impairment. Motor function can be assessed by testing muscle strength, reflexes, and coordination.
Overall, the assessment of sensory and motor function can help identify the level of damage caused by spinal anesthesia and guide treatment decisions.