Answer: Breathing and all limbs (may require ventilator).
- A Mainly leg movement, leaving the arms and trunk unaffected
- B Breathing and all limbs (may require ventilator)
- C Mainly arm movement, sparing the lower limbs largely
- D Mainly bladder control, with limb function largely preserved
Correct answer: B. Breathing and all limbs (may require ventilator)
Explanation: The phrenic nerve (C<sub>3</sub>-C5) controls the diaphragm. Injury above C<sub>4</sub> can affect breathing and all four limbs (quadriplegia).
Structure of a neuron. Image: LadyofHats (Mariana Ruiz), Public Domain, via Wikimedia Commons.
Concept context
Brain, spinal cord, neurons, reflex arcs, and sense organs.