The anterior rami of spinal nerves form which of the following nerve plexuses?

• A. Cervical, brachial, lumbar, and sacral plexuses
• B. Cervical, thoracic, and coccygeal plexuses
• C. Brachial, thoracic, and cranial plexuses
• D. Cranial, thoracic, lumbar, and coccygeal plexuses

Answer: (A)

Verified step by step guidance

1. Understand the anatomy of spinal nerves: Spinal nerves are mixed nerves that emerge from the spinal cord and divide into anterior (ventral) and posterior (dorsal) rami. The anterior rami are responsible for forming nerve plexuses, which are networks of intersecting nerves.
2. Learn the major nerve plexuses formed by the anterior rami: The primary nerve plexuses formed by the anterior rami are the cervical, brachial, lumbar, and sacral plexuses. These plexuses serve different regions of the body, providing motor and sensory innervation.
3. Recognize that thoracic spinal nerves generally do not form plexuses: Unlike the cervical, brachial, lumbar, and sacral regions, the anterior rami of thoracic spinal nerves primarily form intercostal nerves rather than plexuses. This is an important distinction to eliminate incorrect options.
4. Eliminate incorrect answer choices: Review the options provided and eliminate those that include plexuses not formed by anterior rami (e.g., cranial plexuses, which do not exist, or thoracic plexuses, which are not formed by anterior rami). Focus on the correct combination of cervical, brachial, lumbar, and sacral plexuses.
5. Select the correct answer: Based on the anatomical knowledge of spinal nerve plexuses, choose the option that lists cervical, brachial, lumbar, and sacral plexuses as the correct answer.