Point: 2. Anterolateral System
Function:
Pain and temperature from the opposite (contra.) side of the
body (arm, trunk and leg).
Pathway:
Dorsal horn neurons of the spinal cord possess axons that
decussate and ascend as the lateral and ventral
spinothalamic tracts in the anterolateral part of the spinal
cord (A.L.S.). These axons pass through the brainstem to
reach the V.P.L. of the thalamus. Neurons in the V.P.L.
project to somatosensory cortex (areas 3,1, 2).
Deficits:
Loss of pain and temperature from the contra. side of the
body (arm, trunk and leg).
Other Note:
Descending autonomic fibers from the hypothalamus travel
with the ALS in the brainstem on their way to the lateral
cell column (pregang. sym. cells) of ipsi. spinal cord.
Lesion involving ALS=contra. loss pain and temp. AND
CONSTRICTED pupil in IPSI. eye and ptosis.
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