Fascia around nerve bundle of brachial plexus is derived from?
**Core Concept**
The fascia surrounding the brachial plexus is a type of connective tissue that envelops and separates the nerve bundles. It is derived from the mesenchymal cells that migrate from the neural crest during embryonic development.
**Why the Correct Answer is Right**
The fascia around the brachial plexus is derived from the **epineurium**, which is a layer of connective tissue that surrounds individual nerve fibers. As the nerve fibers aggregate to form nerve trunks, the epineurium fuses to form the **perineurium**, which then merges with the **epineurium** of adjacent nerve trunks to form the fascia of the brachial plexus. This fascia plays a crucial role in protecting the nerve bundles from mechanical injury and providing a conduit for the growth of new nerve fibers.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the fascia around the brachial plexus is not derived from the **dura mater**, which is a thick, fibrous membrane that surrounds the brain and spinal cord.
* **Option B:** This option is incorrect because the fascia around the brachial plexus is not derived from the **periosteum**, which is a layer of connective tissue that surrounds bones.
* **Option D:** This option is incorrect because the fascia around the brachial plexus is not derived from the **endoneurium**, which is a thin layer of connective tissue that surrounds individual nerve fibers.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the fascia around the brachial plexus can be a source of pain and discomfort in conditions such as thoracic outlet syndrome, where the compression of the brachial plexus by surrounding tissues can lead to nerve damage.
**Correct Answer: C. Epineurium**