Anatomy Bones and Muscles · MU Pleven

148. Efferent motor systems. Pyramidal system. Oculomotor system.

Covers the efferent motor systems, starting with the pyramidal system's cortico-bulbar and corticospinal tracts, including their routes through the internal capsule, brainstem and decussation. Then it sets out the extrapyramidal tracts in medial and lateral pathways, such as vestibulo-spinal, tectospinal, reticulospinal and rubrospinal, and the oculomotor nerve's extraocular control. It closes with a summary of upper and lower motor neuron connections, with several pictures and a summary section.

Inside: 11 sections · 4 labelled pictures · 10 flashcards · 7 min

Topic 147 of 236 in the MU Pleven syllabus for Anatomy Bones and Muscles (Medicine, Year 2). The free AceMed note covers it in 11 sections, about 1,041 words (7 min of reading), with 10 flashcards.

In this note

  1. Introduction
  2. MOTOR SYSTEM
  3. Pyramidal System :
  4. Extrapyramidal tract :
  5. Corticonuclear (corticobulber) system:
  6. Corticospinal :
  7. Oculomotor :
  8. Medial pathway :
  9. Lateral pathway :
  10. Summary:
  11. Extrapyramidal:

Introduction

177 + 178

MOTOR SYSTEM

The motor system is a complex network of structures and pathways within the nervous system that coordinates and controls voluntary and involuntary movements.

Pyramidal System :

  • This system begins from the pyramidal cells of the primary motor cortex.
  • Axons of these upper neurons descend into the brain stem and spinal cord to synapse with on lower motor neurons that control skeletal muscles.
  • It includes 3 pairs of tracts:
  • Cortico-bulbar tracts: (to motor cranial nerves nuclei in the brain stem).
  • Lateral cortico-spinal tracts: to the spinal cord, running in the lateral white column.
  • Anterior cortico-spinal tracts: to the spinal cord, running in the anterior white column

Extrapyramidal tract :

  • This system is concerned with subconscious regulation of muscle tone and movement, in addition to subconscious control of the balance needed for each movement.
  • It includes 2 pathways:
  • Medial pathway: controlling movements of trunk and proximal limb muscles (vestibulo-spinal, tecto-spinal, and reticulo-spinal tracts).
  • Lateral pathway: controlling distal limb muscles with its more discrete movements (rubro-spinal tracts).

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