Schematic internal structure | Brain-inter-atlas

Nuclei

The gray matter of the spinal cord display several cellular groups that are arranged in nuclei or columns in the axis of the spinal cord. Here are some noteworthy nuclei:

Nuclei of the posterior horn
Nuclei of the lateral horn
Nuclei of the anterior horn

There are also scattered and "solitary" cells widely dispersed over the gray matter: those are the association neurons.

Rexed laminae

Divides the grey matter according to the cell types

Tracts

Dispersed through the three funiculi of white matter
Main ascending tracts
- Gracile and cuneate fasciculi
  The only ones with a consensual location
- Spinal lemniscus
  The main component being the spinothalamic tract
- Posterior spinocerebellar tract
- Anterior spinocerebellar tract
Descending tracts: form two dinstincts functionnal systems
- Pyramidal system
  - Origin: telencéphalon (cerebral cortex)
  - Lateral corticospinal tract
    crossed
  - Anterior corticospinal tract
    direct
- Extrapyramidal system
  - Origin: mesencephalon and rhombencephalon
  - Comprend :
    - Rubrospinal tract
    - Tectospinal tract
    - Medial and lateral vestibulospinal tracts
    - Olivospinal fibres
    - Bulboreticulospinal tract
    - Pontoreticulospinal tract