Final answer:
The sympathetic preganglionic axons may leave the spinal cord at the thoracic and upper lumbar segments, specifically within the thoracolumbar system (T1-L2). The correct segment option is the Seventh thoracic (C).
Step-by-step explanation:
The sympathetic preganglionic axons may leave the spinal cord at the segments of the thoracic and upper lumbar spine. Considering the options provided:
- Second cervical (A) is not correct because it is outside the thoracolumbar range.
- Second sacral (B) is incorrect as it is part of the sacral portion which does not directly give rise to sympathetic preganglionic fibers.
- Seventh thoracic (C) is correct because it is within the thoracolumbar range where sympathetic preganglionic fibers emerge.
- Fifth lumbar (D) is incorrect as it falls outside the typical range of the thoracolumbar system.
The correct answer is Seventh thoracic (C), as it is part of the thoracolumbar system (T1-L2), from which the preganglionic sympathetic axons can emerge to connect to the adjacent ganglia through the ventral spinal roots.