Mind map

Spinal Cord

Julia Morneau English

Map content

Spinal Cord

White Matter: myleinated axons
- Dorsal column
  - posterior
- Ventral Column
  - Anterior
- Lateral column
Grey matter: unmyelinated cell bodies/soma
- Horns: Bring information in/out of spinal cord
  - Dorsal Horn
    - Sensory (visceral and somatic)
  - Lateral Horn
    - Visceral motor
  - Ventral Horn
    - Somatic motor
  - distinguished by type of information they carry
- 2. Choose a horn based on type (sensory v motor) and classification (somatic v visceral)
Roots: Connect spinal nerves to horns
- Dorsal Root
  - Dorsal root ganglion
    - Contains cell bodies
    - Psuedounipolar neurons
- Ventral Root
  - Contains cell bodies
- Distinguished by type of information (sensory or motor)
- 1. Choose a root based on type of information
Rami: Travel from the body to the spinal nerve
- Classified by location of destination or origin
- Ventral Ramus
  - Front sides of body
- Dorsal Ramus
  - Back side of the body
- Communicating Rami
  - Smooth/cardiac muscle, glands
  - Cell bodies located in sympathetic ganglion
    - Sympathetic chain
      - Runs parallel and anterior to spinal cord
  - Visceral motor and sensory
    - Carried to sympathetic trunk
- 3. Choose a ramus based on destination
Pathways
- Ascending: Send sensory information to the brain
  - Neurons
    - 1st order neuron
      - Peripheral sensor neuron
      - Body to dorsal horn
    - 2nd order neuron
      - Interneuron
      - Travels from dorsal horn up lateral column to thalamus
    - 3rd order neuron
      - Interneuron
      - Travels from thalamus to cerebral cortex
        Decussates at pyramids of medulla
    - Cell bodies
      - Located in dorsal horn and thalamus
  - 2 synapses
  - Types
    - Dorsal column-medial leminscus
    - Spinothalamic
    - Spinocerebellar
- Descending: Send instructions to muscles for motor function
  - Neurons
    - Upper motor neuron
      - Interneuron
      - Travels from primary motor cortex to ventral horn through the ventral column
    - Lower motor neuron
      - Motor neuron
      - Travels from the ventral horn to the muscle
    - Cell Bodies
      - Located in ventral horn
  - 1 synapse
Plexuses: Groups of nerves from the ventral rami
- Intercostal nerves
  - Runs along ribs
  - Innervates muscles and skin of abdominal wall, bones
- Cervical plexus
  - Innvervates neck
- Brachial Plexus
  - Innervates arm
  - C5-T1
- Lumbosacral plexus
  - Innervates legs
  - L2-S4
Reflexes
- Polysynaptic Reflex Arc
  - Sensory Neuron (travels along rami to spinal nerve)
    - Dorsal Horn
      - Interneuron (gray matter)
        Ventral horn
        Ventral Root
        Muscle
        Where interneuron synapses
        Can also go outside of spinal column
      - Where sensory neuron synapses with interneuron
- Monosynaptic Reflex Arc
  - Sensory neuron (travels along ramus)
    - Ventral horn
      - Muscle
Anatomy
- Conus Medullaris
  - Termination of spinal cord at L1/L2
- Cauda Equina
  - Bundle of spinal nerve roots that lumbar, sacral, and coccygeal nerves pass through
- Filum Terminale
  - Holds spinal cord down to sacrum and coccyx
  - Continuation of pia mater
- Denticulate ligaments
  - Extention of pia mater that stabilize spinal cord in vertebral canal
- Vertebral foramen
  - Where spinal nerves emerge through foramina in vertebrae, forms vertebral canal
    - Location of spinal cord
- Vertebral canal
  - Where the spinal cord runs through
- Intervertebral foramen
  - Spaces between vertebrae where spinal nerves exit
  - Between vertebrae
Meninges
- Dura Mater
- Arachnoid Mater
- Subarachnoid Space
  - Location of CSF
- Pia Mater
- Central Canal
  - Fluid-filled
  - Continuity with ventricles of brain
- Anterior median fissure
- Epidural Space
  - Filled with fat and blood vessels
Vertebrae
- Cervical
  - 8
- Thoracic
  - 12
- Lumbar
  - 5
- Sacral
  - 5
- Coccygeal
  - 1