Which of the following nerves does NOT reside within the spinal plexus?Question 14Answera.Radial nerveb.Ulnar nervec.Thoracic nerved.Median nerve

Break Down the Problem

1. Identify the spinal plexuses (cervical, brachial, lumbar, sacral).
2. Determine which nerves are part of these plexuses.
3. Identify the nerve that does NOT belong to any spinal plexus.

Relevant Concepts

• Spinal Plexuses: Networks of nerves formed by the ventral rami of spinal nerves. The major plexuses include:

  • Cervical Plexus: Supplies the head, neck, and part of the shoulder.
  • Brachial Plexus: Supplies the upper limb.
  • Lumbar Plexus: Supplies parts of the lower limb.
  • Sacral Plexus: Also supplies parts of the lower limb.

• Thoracic Nerves: The thoracic region consists of T1 to T12 spinal nerves, which primarily innervate the intercostal muscles and do not form a plexus.

Analysis and Detail

1. The radial nerve, ulnar nerve, and median nerve are all part of the brachial plexus, which arises from spinal nerves C5 to T1.
2. The thoracic nerve does not contribute to a plexus; it remains segmental and primarily innervates the chest wall and abdominal muscles.

Verify and Summarize

After analyzing the involvement of each of the indicated nerves, it is clear that the thoracic nerve does not reside within any spinal plexus while the other three nerves are part of the brachial plexus.

Final Answer

c. Thoracic nerve