Nerves

Nerves are bundles of axons outside the central nervous system.

Cranial nerves leave the brain to innervate primarily the head.

Spinal nerves leave the spinal cord to innervate the rest of the body.

 

In typical human nerves, unmyelinated axons outnumber myelinated axons by 2:1.

 

Nerve Structure

Fascicles, surrounded by perinurium, contain axons. Fascicles anastamose with each other, and axons can move between them.

 

 

Nerve Course

In thoracic nerves, subdivision happens in an orderly fashion. In cervical and lumbosacral areas, however, nerve plexuses form, with complex paths ensuing.