Anterolateral system

Question 1

Direct pathway

Answer 1

SC
Lateral thalamus
Somatosensory cortices

Question 2

Indirect pathway

Answer 2

SC
RF
Medial thalamus
Cingulate, frontal, and Limbic cortices

Question 3

Which fibers make up the ALS system

Answer 3

Spinothalamic, spino mesencephalic, spinoreticular, spinobulbar, spinohypothalamic

Question 4

Spinothalamic pathway

Answer 4

Spine
Thalamus
VPL and VPI

Question 5

Spinomesencephalic pathway

Answer 5

Spine

Midbrain RF and PAG

Question 6

Spinobulbar pathway

Answer 6

Spine

various nuclie of the brain

Question 7

SPinohypothalamic pathway

Answer 7

Spine

Hpothalamus and other nuclei

Question 8

SPinoreticular pathway

Answer 8

Spine

Medulla, pons, midbrain (RF)

Question 9

ALS SC blood supply. Injury?

Answer 9

sulcal branches anterior spinal a

Occlusion leads to patchy losses of nociceptive, thermal touch over CL side of body 2 segments below lesion. Anterolateral cordotomy results in complete loss.

Question 10

ALS in medulla blood supply and injury?

Answer 10

Caudal 1/3rd: vertebral A
Rostral 2/3rds: PICA (occlusion results in loss of pain/temp over CL body and IL loss of pain/temp of face b/c of spinal trigeminal nucleus and tract)

Question 11

ALS in pons blood supply

Answer 11

long circumferential branches of basilar

Question 12

ALS in midbrain blood supply

Answer 12

short circumferential branches of posterior cerebral (also does PCML) and superior cerebellar A

Question 13

Upper cervical lesion sx

Answer 13

Deficit of entire CL side of body

Question 14

Upper thoracic lesion

Answer 14

Deficit in thorax and LE on CL side. UE is ok because they enter into the pathway more rostrally.

Question 15

When do the tracts cross

Answer 15

In the anterior white commissure in the spinal cord

Question 16

Spinal cord hemisection sx. Have the tracts crossed? What other systems are involved?

Answer 16

The ALS tracts have crossed! Involves ALS, PCML, and CTS.

CL ALS loss 2 levels below lesion (bc have crossed already)
IL PCML loss below lesion (these don’t cross until caudal medulla)
IL paralysis below lesion (CTS)
IL horner if at cervical levels

Question 17

Caudal pons lesion sx. What other systems are invovled?/

Answer 17

ALS in medulla, ML in medulla, and spinal trigeminal tract and nucleus, ambiguus, area postrema

IL facial and lateral rectus paralysis (facial nucleus damage=IL loss)
IL facial loss of pain/therm
IL Horners
ALS loss of CL limbs and IL face (alternating hemianesthesia)
Dysphagia and dysarthria
NV (area postrema)

Question 18

Mid to rostral pons lesion sx. What systems are invovled?

Answer 18

PCML, ALS, trigeminal nuclei

CL limb PCML and ALS loss
IL pain/therm and discrimative touch to face, paralysis of masticatory muscles

Question 19

Midbrain lesion sx. Systems?

Answer 19

ALS, ML, and red nucleus

CL limb ALS loss
CL LE PCML loss; if more medial, include CL UE.

Question 20

VPL lesion sx.

Answer 20

Transient CL hemiplegia
CL paresthesias to face, trunk, and UE/LE
CL facial/oral cavity (if VPM included) loss /diminution of pain/therm/proprio, as well as on CL limbs.

Question 21

What is the target of primary afferents entering into the ALS sytem

Answer 21

Laminae I, II, and V of posterior horn

Question 22

Once fibers are in the spinal cord, what do they move within

Answer 22

Move within the posterolateral fasciculus (Lissauer tract).

Question 23

Which NTs are involved in rhe DRGs?

Answer 23

Glutamate, calcitonin-gene related peptide (CGRP), and substance P. Project most heavily onto laminae II.

Question 24

Spinomesencephalic fibers contain what NT

Answer 24

VIP. For vasodilation.