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CHAPTER 23
sclerosis. Isolated damage to the pyramidal tracts following acute injury of the spinal
cord is very rare but it is not uncommon as residual syndrome following rcovery of
incomplete traumatic lesions and following removal of extramedullary tumours of the
spinal cord.
Combined anterior horn and pyramidal tract syndrome
The clinical picture is characterized by muscular paralysis of peripheral type, combined
with pyramidal signs such as exaggeration of reflexes and pathological reflexes such as
spastic finger-flexion reflex, Babinski, etc. Corresponding to the number of affected
muscles of lower motor neuron damage, the hyperreflexia may disappear in later stages.
Amyotrophic lateral sclerosis is the classical representative of this combined anterior
horn and pyramidal tract involvement. Fibrillations and fasciculation of muscles are the
early manifestations of degenerative changes of the anterior horn cells.
Combined anterior horn and anterolateral tract syndrome
This is a relatively frequent syndrome in incomplete lesions of the cord, characterized
by segmental muscular paralysis of lower motor neuron type and, below the level of the
lesion, by bilateral spasticity and dissociated sensory loss—i.e. analgesia and thermo-
anaesthesia—while touch and posterior column sensibility remain intact. This syndrome
is caused by damage to the anterior spinal artery following fracture dislocations of the
spine, anterior spinal artery thrombosis or compression of extramedullary tumours.
Bladder, bowels and sexual functions are also involved.
Combined posterior column and lateral tract syndrome
Loss of posterior column sensibility resulting in ataxy combined with spasticity due to
pyramidal tract involvement is the clinical symptom. This syndrome may be due to
impairment of the posterior spinal arteries supply, toxic and degenerative processes,
deficiency disease, traumatic lesions or tumours compressing the posterior aspect of the
cord. Subacute combined degeneration of the cord (posterior lateral sclerosis) associated
with progressive pernicious anaemia is the classical example of this syndrome due to a
deficiency disease, while Friedreich's ataxia represents the hereditary degenerative form
of this syndrome. The degeneration is most marked in the posterior columns, especially
the fasciculus gracilis, being more pronounced in the lower part of the cord, although the
pyramidal and dorsal spinocerebellar tracts as well as Clarke's column are also involved.
Brown (1892) described a variety of hereditary ataxy in five successive generations of the
same family. While the histological examination revealed degeneration of the cells of
Clarke's column, the posterior columns and the dorsal spinocerebellar tracts, there was
practically no degeneration of the pyramidal tracts.
Central syndromes
The two classical representations of a central damage or destruction of the spinal cord
are haematomyelia and syringomyelia. While the former is characterized by an acute
