Abstract
It is generally thought that the corticobulbar tract descends through the genu of
the internal capsule (IC). There have been several reports that genu lesions cause
bulbar symptoms such as facial palsies, dysarthria, and dysphagia. However, the precise
location of the corticobulbar tract in the IC remains controversial. The purpose of
our study is to assess whether the corticobulbar tract passes through the IC genu.
We reviewed 26 patients with selective IC infarction and located the sites related
to bulbar symptoms. In addition, using diffusion tensor imaging, we reconstructed
tracts passing through the IC in ten subjects without cerebral infarction. Patients
with genu infarction, which extended to more than half of the posterior limb of the
IC, showed bulbar symptoms. However, patients with genu infarction, which was limited
to the genu, did not have bulbar symptoms. In contrast, patients with lesions limited
to the posterior limb may show bulbar symptoms. According to statistical maps of the
region of interest, the lesions related to bulbar symptoms were localized to areas
that were beyond the midpoint of the posterior limb of the IC. In diffusion tensor
imaging of subjects without cerebral infarctions, the corticobulbar and corticospinal
tracts did not pass through the IC genu. Our data provide evidence that the corticobulbar
tract does not pass through the IC genu. The proposed location of the corticobulbar
tract in the level of the IC lies beyond the midpoint of the posterior limb.
Keywords
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Article info
Publication history
Published online: September 12, 2013
Accepted:
July 22,
2013
Received in revised form:
June 14,
2013
Received:
April 11,
2013
Identification
Copyright
© 2013 Elsevier B.V. Published by Elsevier Inc. All rights reserved.
