Inner ear
Pathways
Topography
397
Auditory and equiiibrium pathway
Corpus
geniculatum
mediale
Nucleus
olivaris superior
Nucleus
olivaris inferior
Nucleus
cochlearis posterior
Nucleus cochlearis anterior
Nucleus corporis trapezoidei
Radialio
acustica
Colliculus
interior
Nucleus
lemmsci lateralis
Lemniscus lateralis
N vestibulo-
cochlearis [VIII],
N cochlearis
cochlearis
Fig. 720
Auditory pathway;
overview.
Auditory pathway
1
neuron: Bipolar cells in the spiral cochlear
ganglion. After exiting the small apertures
of the foraminous spiral tract within the
internal acoustic meatus, the fibres form the
cochlear nerve and unite with the vestibular
nerve at the floor of the internal acoustic
meatus to form the vestibulocochlear nerve
[VIII]. Fibres from the basal cochlear parts
traverse to the posterior cochlear nucleus
and those from the apical parts terminate
in the anterior cochlear nucleus
2.
neuron: Multi-polar ganglion cells of the
cochlear nuclei. The fibres from the anterior
cochlear nucleus pass mainly within the
trapezoid body to the opposite side and form
the lateral lemnicus, which provides a con-
nection to the inferior colliculus A few fibres
join the lateral lemniscus of the same side.
The axons of the posterior cochlear nucleus
cross superficially to the rhomboid fossa
and enter the lateral lemniscus of the
opposite side.
3.
or 4
neuron: From the inferior colliculus
connections are made with the medial genic-
ulate body.
4.
or 5. neuron: The acoustic radiation con-
nects
the
medial
geniculate
body
to
HESCHL's
transverse
gyrus
and
with
WERNICKES centre in the temporal lobe.
Equilibrium pathway
1.
neuron: Bipolar cells in the vestibular gan-
glion. Their neurites pass the inferior and
superior vestibular areas to form the vestib-
ular nerve at the floor of the
internal
acoustic meatus, which together with the
cochlear nerve then forms the vestibulo-
cochlear nerve [VIII]. These fibres terminate
at the vestibular nuclei in the lateral angle
of the floor of the rhomboid fossa.
2.
and subsequent neurons: Fibres originating
in the lateral vestibular nucleus IDEITERS’
nucleus) traverse within the lateral vestib-
ulospinal tract to the anterior column of the
spinal cord.
Fibres originating in the superior vestibular
nucleus Inucleus of BECHTEREW), the medial
vestibular nucleus (SCHWALBE'S nucleus) as
well as the inferior vestibular nucleus
(ROLLER'S nucleus) traverse to the cere-
bellum and connect to the motor nuclei of
the cranial nerves III, IV and VI, mostly via
the medial longitudinal fasciculus.
The medial vestibular nucleus and the infe-
rior vestibular nucleus send fibres along the
medial vestibulospinal tract to the anterior
column of the spinal cord
Thalamus
Nucleus
mlerstitialis
nervi oculomotorii
Nucleus
nervi trochlearis
(Tractus
vestibulothalamicus)
Fasciculus
longitudinalis
medialis
Nucleus
vestibularis inferior
Ganglion
vestibuläre
Nucleus
nervi abducentis
N. vestibulo-
cochlearis [VIII],
N, vestibularis
Nucleus vestibularis
superior
Nucleus vestibularis
lateralis
Nucleus
vestibularis medialis
Nucleus cuneatus
Fig. 721
Equ ilibrium pathway;
overview.
* C onnections to the cerebetlum
