Spinal Tracts Simplified

spinal tracts

Organization of Ascending and Descending Tracts in Spinal Cord

A. 2 Posterior Tracts:

The fibers of these tracts cross to the opposite side at the level of medulla:

  1. Dorsal column (Cross at medulla)
    • Fasciculus gracilis
    • Fasciculus cuneatus
  2. Lateral corticospinal tract (Cross at medulla)

B. 2 Lateral Tracts:

The fibers of these tracts remain on ipsilateral side:

  1. Dorsal spinocerebellar tract (Do not cross)
  2. Ventral spinocerebellar tract (Crosses 2 times to lie on ipsilateral side)
    • 1st crossing in the spinal cord
    • 2nd crossing in the cerebellum

C. 2 Anterior Tracts:

The fibers of these tracts cross at the level of spinal cord:

  1. Anterior corticospinal tract
  2. Anterior and Lateral spinothalamic tract

D. Extrapyramidal tracts:

  1. Rubrospinal tract (Cross at midbrain)
  2. Vestibulospinal tract: Uncrossed
  3. Reticulospinal tract: Uncrossed
  4. Olivospinal tract: Uncrossed

spinal tract somatotropy

Now, look at the somatotropic arrangement of the various tracts:

  • Fasciculus gracilis: lower limbs
  • Fasciculus cuneatus: upper limbs
  • Corticospinal tract: upper limbs medially and lower limbs laterally
  • Spinothalamic tract: upper limbs medially and lower limbs laterally

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