Medial Motor Systems

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Medial Motor Systems

Medial motor systems refer to the 4 descending spinal tracts:

• Medial Corticospinal tract¹
• Vestibulospinal tracts (VSTs)¹
  • Medial VST¹
  • Lateral VST¹
• Reticulospinal tracts¹
• Tectospinal tracts¹

Note

All of these tracts besides Medial Corticospinal tract are extrapyramidal tracts

Somatotopic organization of medial and lateral motor system Projections to Anterior Horn Cells¹

Pathway

The medial motor systems descend ipsilaterally or bilaterally.

Some extend only to the upper few cervical segments (see Table 6.3; Figure 6.11C–E). The number of segments each extend vary:

• The Lateral VST extends the entire cord¹
• The Reticulospinal tracts extends the entire cord¹
• The Medial Corticospinal tract extends to the cervical and upper thoracic cord¹
• The Medial VST extends to the cervical and upper thoracic cord¹
• The Tectospinal tracts only extends to the cervical cord¹

Function

The medial motor systems send motor efferent to the proximal axial and girdle muscles which allow for:

• Postural tone¹
• Balance¹
• Orienting movements of the head and neck¹
• Automatic gait-related movements¹

References

1.

Blumenfeld H. Neuroanatomy Through Clinical Cases. 3rd ed. Oxford university press; 2022.