Psychology Wiki

Assessment | Biopsychology | Comparative | Cognitive | Developmental | Language | Individual differences | Personality | Philosophy | Social |
Methods | Statistics | Clinical | Educational | Industrial | Professional items | World psychology |

Biological: Behavioural genetics · Evolutionary psychology · Neuroanatomy · Neurochemistry · Neuroendocrinology · Neuroscience · Psychoneuroimmunology · Physiological Psychology · Psychopharmacology (Index, Outline)

Posterolateral tract
Diagram showing a few of the connections of afferent (sensory) fibers of the posterior root with the efferent fibers from the ventral column and with the various long ascending fasciculi. (Lissauer's fasciculus visible in upper left.)
Latin t. posterolateralis
Gray's subject #185 762
MeSH [1]
Diagram of the principal fasciculi of the spinal cord. (Lissauer's fasciculus visible in upper right.)

The posterolateral tract (fasciculus of Lissauer, tract of Lissauer, dorsolateral fasciculus) is a small strand situated in relation to the tip of the posterior column close to the entrance of the posterior nerve roots.

Composition and path

It consists of fine fibers which do not receive their medullary sheaths until toward the close of fetal life.

It is usually regarded as being formed by some of the fibers of the posterior nerve roots, which ascend for a short distance in the tract and then enter the posterior column, but since its fibers are myelinated later than those of the posterior nerve roots, and do not undergo degeneration in locomotor ataxia, they are probably intersegmental in character.

In addition it contains great numbers of fine non-medullated fibers derived mostly from the dorsal roots but partly endogenous in origin.

These fibers are intimately related to the substantia gelatinosa which is probably the terminal nucleus.

The non-medullated fibers ascend or descend for short distances not exceeding one or two segments, but most of them enter the substantia gelatinosa at or near the level of their origin.

Clinical significance

During a complete occlusion of the ventral artery of the spinal cord, it is the only tract spared along with the dorsal columns.


The tract of Lissauer was named after German neurologist Heinrich Lissauer (1861-1891).

External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

Spinal cord

epidural space, dura mater, subdural space, arachnoid mater, subarachnoid space, pia mater, denticulate ligaments, conus medullaris, cauda equina, filum terminale, cervical enlargement, lumbar enlargement, anterior median fissure, dorsal root, dorsal root ganglion, dorsal ramus, ventral root, ventral ramus, sympathetic trunk, gray ramus communicans, white ramus communicans

grey matter: central canal, substantia gelatinosa of Rolando, reticular formation, substantia gelatinosa centralis, interneuron, anterior horn, lateral horn, posterior horn (column of Clarke, dorsal spinocerebellar tract)

white matter: anterior funiculus: descending (anterior corticospinal tract, vestibulospinal fasciculus, tectospinal tract), ascending (anterior spinothalamic tract, anterior proper fasciculus)

lateral funiculus: descending (lateral corticospinal tract, rubrospinal tract, olivospinal tract), ascending dorsal spinocerebellar tract, ventral spinocerebellar tract, spinothalamic tract, lateral spinothalamic tract, anterior spinothalamic tract, spinotectal tract, posterolateral tract, lateral proper fasciculus, medial longitudinal fasciculus

posterior funiculus: fasciculus gracilis, fasciculus cuneatus, posterior proper fasciculus

This page uses Creative Commons Licensed content from Wikipedia (view authors).