Spinal Cord Flashcards
This deck tests your knowledge of the anatomy and physiology of the spinal cord.
What are the spinal vertebrae?
C 1-8
T 1-12
L 1-5
S 1-5
Describe the three spinal meninges?
- Dura mater - tough outer layer
- Arachnoid mater - thin, spidery, intermediate vascular layer
- Pia mater - delicate deep layer
What is a spinal segment?
The region of a spinal cord where a certain spinal root exits
Does a spinal segment align with the spinal vertebrae?
No, as the spinal cord is shorter than the spine
What are some important spinal segments?
- C3 - C5: phrenic nerve (respiratory)
- C5 - T1: brachial plexus (UL)
- L1 - S4: lumbosacral plexus (LL)
- S2 - S4: sphincter nerves
Draw out the arterial supply of the spinal cord.
Refer to Notion.
Draw out the ascending (sensory) spinal tracts.
Refer to Notion.
What are the components of the dorsal column medial lemniscus?
- Fasciculus gracilis
- Fasciculus cuneatus
What does the fasciculus gracilis transmit?
- Fine sensory info (fine touch, two-point discrimination, vibration, conscious proprioception) from below T6
- Ascend ipsilaterally > decussate in medulla > thalamus > somatosensory cortex
Give an example of a fasciculus gracilis lesion, and what effects it would have.
- Tabes dorsalis
- Lesions lead to loss of fine sensations below T6; may be contralateral / ipsilateral depending on site
What does the fasciculus cuneatus transmit?
- Fine sensory info (fine touch, two-point discrimination, vibration, conscious proprioception) from above T6
- Ascend ipsilaterally > decussate in medulla > thalamus > somatosensory cortex
Give an example of a fasciculus cuneatus lesion, and what effects it would have.
- Tabes dorsalis
- Lesions lead to loss of fine sensations above T6; may be contralateral / ipsilateral depending on site
What are the components of the spinocerebellar tract?
- Dorsal SCT
- Ventral SCT
What does the dorsal SCT transmit?
- Unconscious proprioception (muscle length, rate of change of muscle length, force exerted) from lower limbs and trunk
- Synapse in dorsal horn > ascend ipsilaterally to cerebellum
Give an example of a dorsal SCT lesion, and what effects it would have.
- Friedrich’s ataxia
- Lesions lead to ipsilateral loss of lower limb coordination
What does the ventral SCT transmit?
- Unconscious proprioception (spinal interneuron activity; for fine-tuning of motor movements) of lower limbs and trunk
- Synapses on lumbosacral dorsal horn > decussates > ascends > decussates > ascends to cerebellum
Give an example of a ventral SCT lesion, and what effects it would have.
- Friedrich’s ataxia
- Lesions lead to ipsilateral loss of lower limb coordination
What are the components of the spinothalamic tract?
- Lateral STT
- Ventral STT
What does the lateral STT transmit?
- Crude sensory info (crude touch, temperature, pain) from body
- Synapses on dorsal horn > decussates > thalamus > somatosensory cortex
Give an example of a lateral / ventral STT lesion, and what effects it would have.
- Brown-Sequard syndrome (hemisection of spinal cord)
- Contralateral loss of crude sensations + ipsilateral loss of fine sensations (DCML)
What does the ventral STT transmit?
- Crude sensory info (pressure, crude touch) from body
- Synapses on dorsal horn > decussates > thalamus > somatosensory cortex
What are the four special sensory tracts?
- Trigemino-thalamic tract
- Spino-olivary tract
- Spino-tectal tract
- Spino-reticular tract
What does the trigemino-thalamic tract transmit?
- All sensations (touch, pressure, pain, temperature, proprioception) from face
- V1, V2, V3 > trigeminal sensory nucleus complex > decussate > thalamus > cortex
What effects would occur in a trigemino-thalamic tract lesion?
Contralateral loss of sensation from face
