Spinal Cord Flashcards Preview

Neuroanatomy > Spinal Cord > Flashcards

Flashcards in Spinal Cord Deck (39)
Loading flashcards...

What is the conus medullaris?

Terminal point of the spinal cord @ ~L1-L2


What are the meningeal coverings of the SC

Brown - dura mater

Green = arachnoid mater

Red = pia mater


Describe the spaces in the SC

Red = epidural space (fat and venous plexus)

Yellow = subarachnoid space (CSF and spinal blood vessels)


What are denticulate ligaments

Thickening of pia and glial elements that form ribbons along lateral surface of SC


What is the filum terminalae

Extension of pia and supporting cells that connects the conus medullaris to the coccyx bone


Label the following

Posterior (posterolateral sulcus) -- where sensory info enters

Posterior median fissure

Anterolateral sulcus -- where motor info exits

Anterior median fissure



Differences between SC sections at cervical, thoracic and lumbar segments?

  • Cervical and lumbar have the most grey matter because they innervate the limbs
  • Cervical white matter > thoracic > lumbar because motor information from all spinal segments is carried at the most caudal sections


Two sources of spinal cord blood supply

  1. Vertebral basilar system
  • PICAs and vertebral arteries join to form the posterior spinal artery and anterior spinal artery
  1. Segmental arteries
  • Posterior brances of intercostal arteries give rise to segmental spinal arteries
  • Segmental spinal arteries branch to form either (a) radicular arteries that supply roots at each level of SC or (b) segmental medullary arteries which supply either the PSA or the ASA
  • Segmental p


Where do segmental spinal arteries originate

Anterior intercostal arteries


What originates from segmental spinal arteries

1) Radicular arteries (supplies roots)

2) Segmental medullary arteries (supply the ASA or the PSA)


Describe the blood supply from the ASA and PSA to the SC

  • The ASA supplies the anterior 2 thirds of the SC, including the base of the posterior horns
  • The PSAs supply the posterior 1/3 of the SC


What is the composition of a spinal nerve

1) Sensory root (afferent) to posterolateral sulcus

2) Motor root (efferent) exiting from anterolateral sulcus


Number of cervical vertebrae and nerves

CI - CVII (7 vertebrae)

C1-C8 (8 nerves)


Number of thoracic nerves and vertebrae

TI - TXII (12 vertebrae)

T1-T12 (12 nerves)


Number of lumbar nerves and vertebrae

LI-LV (5 vertebrae)

L1-L5 (5 nerves)


Number of Sacral nerves and vertebrae

5 vertebrae fused as sacrum

5 nerves (S1-S5)


Number of Coccygeal nerves and vertebrae

1-4 coccygeal vertebrae (fused as coccyx)

1 nerve (C0)


Where are the sympathetic nervous system efferents in the SC?

T1-L2 segments; cell bodies are in LATERAL HORNS in thoracic cross-sections


Where are the parasympathetic visceral efferents in the SC?



Where are the SC enlargements?

  1. Cervical: C4/5 - T1
  2. Lumbosaral: L2-S3


What is visible in a SC cross-section from T1-L2/3?

Lateral horn (intermediolateral cell column)

-contain preganglionic sympathetic cell bodies


What is visible in a SC cross-section at S2-S4

Lateral horn

Preganglioic parasympathetic cell bodies


What type of information is carried by General Somatic Afferents (GSAs)

  • Discriminative Touch
  • Proprioception
  • Somatic pain and temperature


What type of information is carried by General Visceral Afferents?

  • Sensation from the viscera


What type of information is carried by General Somatic Efferents?

  • motor to skeletal muscles


What type of info is carried by General Visceral efferents

Motor to viscera

  • Originates in lateral horns, exits via the anterolateral sulcus, travels through motor roots to spinal nerve


Interomediolateral nucleus

Cell bodies of visceral motor efferents found only in T1-L2 (SYMPATHETIC) and S2-S4 (parasympathetic efferents)



Where are parasympathetic motor (efferent) nerves found?

  1. Cranial nerves 9-12
  2. S2-S4 of spinal cord


Which laminae are present in the dorsal (posterior) horns?

Rexed laminae I - VI:

I = Posterior (dorsal) root fibers mediating pain, temperature, and touch; posteromarglnal nucleus

II: Subatantla gelatinosa neurons mediating pain transmission

III and IV: Proper sensory nucleus receiving Inputs from substantla gelatinosa and contributing to anterolateral system

V: Neurons receiving afferent Input from vlscera, skin, and muscle

VI: (only in cervical): afferents from muscle spindles