Spinal cord Flashcards
How many sections to each part?
-Cervical 8
-Thoracic 12
-Lumbar 5
-Sacral 5
-Coccygeal 1
=31 PAIRS
Where is the ventral root on the spinal cord?
ventral = front (motor tract) dorsal = at the back (sensory tracts)
What protects the spinal cord?
The meninges (PAD) -Pia mater -arachnoid mater -dura mater
Name the 4 main ascending tracts, what do they sense
- Medial lemniscal/dorsal column = proprioception, vibration, discriminative touch
a) fasciculus gracilis medial = lower body ends in gracile nucleus
b) fasciculus cunetaus = upper body, ends in the cuneate nucleus
* crosses at the medulla then ascendsto the thalamus and cortex* - Spinothalamic
lateral = pain and temp
medial = crude touch
crosses at spinal cord before ascending to the thalamus (most cross at thalamus) - Spinocerebellar = proprioception
a. dorsal ipsilateral cerebellum
b. venteral contra and ipsilateral cerebellum - Spinoreticular = deep/chronic pain
Where do the spinothalamic tract and medial lemniscus end?
The spinothalamic tract and medial lemniscus end in the ventral posteriolateral division (VPL) of the nucleus of the thalamus
Name 5 main descending tracts, what is their function?
- Corticospinal - control of voluntary muscles
- Tectospinal - head turning in response to visual stimuli
- Rubrospinal - assists in motor functions
- Vestibular spinal - control of posture and tone
- Recticular spinal - spinal reflexes
What is the ventrolateral system?
- The spinorectiulo thalamic pathway and the spinothalamic tract
- pain, touch, crude touch & deep/chronic pain
What does the trigeminothalamic pathway do?
Pain and temp sensory for the head
- cross at midline
- terminate in Ventro Posteromedial nucelus of the thalamus (not VPL - vetro posterolateral nucleus)
What does a complete spinal cord leison cause?
- Weakness in all muscle groups below the site of lesion
- spasticity and hyper-reflexia (loss of descending inhibition to MNs)
- Complete sensory loss below leison
What is Brown-séquard syndrome?
-Hemisection of spinal cord
=ipslateral weakness below region
=ipslateral loss of dorsal column proprioception below lesion
=CONTRALATERAL loss of spino-thalamic pain and temp below region (fibres cross just after entering spinal cord)
Name the tracts of the medial lemniscal/dorsal column, what do they sense and where do they cross
- fasciculus cuneatus = senses proprioception, vibration and discriminative touch of the UPPER BODY
1st-ascends to the medulla, crosses and then ascends to the cuneate nucleus in the medulla
2st-then ascends to the thalamus - VPL nucelus
3rd-primary sensory cortex - fasciculus gracilis = senses proprioception, vibration and discriminative touch of the LOWER BODY
1st-ascends to the medulla, crosses and then ascends to the gracile nucleus in the medulla
2nd - thalamus VPL nucelus
3rd- primary sensory cortex
What does the spinothalamic tract sense?
- Lateral - pain and touch
- Medial - crude touch
- ascend on the same side and then CROSS before ascending the VPL in thalamus then to the somatosensory cortex
- somatotopic organization
(this is why contra lateral pain and temp is lost in brown-séquad syndrome)
What does spinocerebeullar tract sense?
- Proprioception (length and tension of muscle fibres)
a) dorsal ipislateral cerebeullm
b) ventral contra and ipsilateral cerebellum
Both convey info to same side of cerebellum
What does spinoreticular sense?
Deep/chronic pain
What can occur due to an inflamed or herniated disc?
Stimulates pain and temp fibres causing burning sensations in area supplied by the nerve root
(C4 = shoulder, C10 = umbilicus, L5 = big toe)
