Overview of the CNS and major spinal pathways
Classification of CNS
- Spinal cord
- Hindbrain (e.g. medulla, pons)
- Midbrain
- Forebrain includes Diencephalon (Thalamus, Hypothalamus, Pituitary) and
Telencephalon (Subcortex, Cerebral cortex)
Spinal Cord segments
- Cervical = Head, Neck, Upper limb (+/- some chest, diaphragm)
- Thoracic = Chest, Abdomen
- Lumbar = Lower limb
- Sacrum = Pelvis
Classification of pathways
- Somatic motor = muscles
- Somatic sensation = skin (pain, temp), muscles/tendons (deep pain) ,
joints (proprioceptive/joint position sense/JPS)
- Visceral motor (autonomic) = gland secretion, vessel tone
- Visceral sensory = visceral capsules e.g. liver/renal capsule
- Special sense = vision, hearing, balance
A simpler classification of pathways
- Somatomotor
- Somatosensory
- Special sense
- Autonomic (sympathetic vs parasympathetic) * - which have visceral
afferents and efferents
* Sympathetic pathways exit cord at thoraco-lumbar level* Parasympathetic
pathways exit brainstem (cranial outflow) or sacral segments