Spinal cord

Rohit Sharma and Dr Henry Knipe et al.

The spinal cord is the part of the central nervous system that is found within the vertebral canal of the vertebral column. 

It measures approximately 42-45 cm in length, ~1 cm in diameter and 35 g in weight. 

It is divided into cervical, thoracic and lumbar parts and terminates at the conus medullaris at approximately the T12/L1 vertebral body level. 

The spinal cord is segmented by the nerve roots that emerge from it. There are 31 nerve roots in total:

  • 8 cervical
  • 12 thoracic
  • 5 lumbar
  • 5 sacral
  • 1 coccygeal

Like the brain, there is grey and white matter, however, opposite to the brain, the grey matter is on the internal aspect of the cord and the white matter tracts are external.

A transverse section of the spinal cord shows a peripheral mass of white matter enclosing a central mass of grey matter with a small central canal filled with CSF 2.  The central canal is lined by a single layer of ependymal cells.  Surrounding this canal is the ‘H’ or butterfly shaped grey matter.  The cord is incompletely divided into left and right halves by the posterior median sulcus and the anterior median fissure.  The central limb of the ‘H’ connects the left and right halves of the grey matter, known as the grey commissure.  Anterior to the grey matter, the white commissure connects both halves of the white matter.

The grey matter contains the cell bodies of neurons and glia, and is divided into anterior, dorsal and lateral horns 3:

  • the anterior horn contains motor neurons for skeletal muscle
  • the lateral horn contains autonomic neurons for pelvic and visceral organs
  • the dorsal horns receive somatosensory information from the posterior roots of the spinal nerves

The grey matter is enlarged in the cervical and lumbosacral regions to provide fibres to the large nerve plexuses.

The white matter contains nerve fibres or tracts, and is divided into anterior, dorsal or lateral columns 3

  • the dorsal columns contain ascending fibres which are responsible for vibration, conscious proprioception, and fine (discriminative) touch sensations
  • the lateral columns primarily contains the corticospinal tracts which are the principal motor pathway connecting the cerebral cortex to spinal motor neurons
  • the anterior columns primarily contains the spinothalamic tracts which are responsible for pain, temperature, coarse (non-discriminative) touch, and pressure sensations 

In general, neurons found posteriorly process and relay sensory information, neurons round laterally are preganglionic visceral motor neurons and somatic motor neurons are found anteriorly 4

See spinal cord blood supply.

Neuroanatomy
Spinal anatomy
Share article

Article information

rID: 25075
Section: Anatomy
Tags: refs, craig
Synonyms or Alternate Spellings:
  • Spinal cord anatomy

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Case 1: normal MRI appearance
    Drag here to reorder.
  • Drag
    Posterolateral vi...
    Figure 1
    Drag here to reorder.
  • Drag
    Superior view of ...
    Figure 2: vertebra
    Drag here to reorder.
  • Drag
    Spinal tracts. Im...
    Figure 3: spinal tracts
    Drag here to reorder.
  • Drag
    Figure 4: spinal cord cross section (Gray's illustration)
    Drag here to reorder.
  • Drag
    Figure 5: spinal cord cross section (Gray's illustration)
    Drag here to reorder.
  • Drag
    Figure 4: spinal cord cross section lateral view (Gray's illustration)
    Drag here to reorder.
  • Drag
    Figure 6: spinal cord cross section at different levels (Gray's illustration)
    Drag here to reorder.
  • Drag
    Figure 7: arterial supply
    Drag here to reorder.
  • Drag
    Figure 8: spinal tracts
    Drag here to reorder.
  • Drag
    Figure 9: spinal tracts (axial)
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.