Spinal cord definition and central canal

Summary

The spinal cord is a long, thin, tubular structure of nervous tissue that extends from the lower brainstem (medulla oblongata) down to the lumbar region of the vertebral column in vertebrate animals. In humans, it is a continuation of the brainstem, begins at the occipital bone after passing through the foramen magnum, and enters the spinal canal at the start of the cervical vertebrae. It tapers down to end between the first and second lumbar vertebrae (around L1–L2), where it becomes the cauda equina. The center of the spinal cord is hollow and contains the central canal, which is an extension of the fourth ventricle and holds cerebrospinal fluid (CSF). The spinal cord is also covered by the meninges and enclosed by the neural arches, with its internal organization including gray matter around the central canal and white matter surrounding it. This arrangement supports the spinal cord’s role as a major pathway for information between the brain and the peripheral nervous system.

Key Points

• 1

  The spinal cord is a nervous-tissue tube running from the medulla oblongata to the lumbar region, protected by the vertebral column and meninges.

• 2

  The central canal is the hollow space at the center of the spinal cord and contains cerebrospinal fluid (CSF).

• 3

  In humans, the spinal cord does not extend the full length of the vertebral column; it ends around L1–L2 and continues inferiorly as the cauda equina.