The peripheral nerve sheath refers to the protective covering or layer that surrounds and supports peripheral nerves. It is composed of specialized cells called Schwann cells, which play a crucial role in maintaining the integrity and function of the peripheral nerves.
The peripheral nerve sheath consists of two main components:
Endoneurium: This is the innermost layer of the peripheral nerve sheath and surrounds individual nerve fibers within the nerve. It provides structural support and contains blood vessels that supply nutrients to the nerve fibers.
Perineurium: The perineurium is the middle layer of the peripheral nerve sheath and forms a barrier around bundles of nerve fibers called fascicles. It helps maintain the internal environment of the fascicles and protects them from external influences.
In addition to its protective role, the peripheral nerve sheath is involved in various physiological processes, such as nerve regeneration and insulation of nerve fibers to enhance their conduction efficiency.
Disorders or abnormalities affecting the peripheral nerve sheath can lead to nerve-related conditions, including peripheral neuropathies, nerve tumors (such as peripheral nerve sheath tumors or neurofibromas), and other neurologic disorders. Proper evaluation and diagnosis by a healthcare professional are essential for determining the specific condition and guiding appropriate management.