Point
2
Intro
Pathway
Deficits
Summary
Problems
Contents
Anatomy
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The central processes of delta and C fibers
in the lateral division of the dorsal root do
something quite different than the alpha-betas. These
axons enter a zone at the top of the dorsal horn called the
zone of Lissauer (ZL) and then course ROSTRALLY for
approximately 2 spinal segments within this zone
before they dive into the dorsal horn, where they
synapse. THERE HAS BEEN NO CROSSING
YET!!!!! Cells in the
DORSAL HORN that receive this pain and
temperature information then send
axons which CROSS and enter the anterolateral
portion of the lateral funiculus, where they ascend to the
thalamus (the great gateway to the cortex). In particular,
they terminate in the ventral posterolateral nucleus
(VPL). The VPL then relays the information to the
somatosensory cortex (Areas 3, 1, and 2). Information
carried over the pain, temperature and crude touch pathway
begins in the processes of dorsal root ganglion cells, but
the ANTEROLATERAL SYSTEM ( [ALS] axons in the
anterolateral part of the white matter) TAKES ORIGIN FROM
CELLS IN THE CONTRALATERAL DORSAL HORN. THIS SYSTEM IS ALSO
CALLED THE SPINOTHALAMIC PATHWAY (ORIGIN IN SPINAL
CORD, TERMINATION IN THALAMUS).
As the fibers enter the
ALS to ascend they are organized such that the most caudal
fibers (sacral-coccygeal) lie laterally within the ALS.
Compare this with the dorsal column system!!!
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