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Page 1 of 5
Clinical Anatomy
Critical review
Clinical anatomy of the fourth ventricle foramina
Abstract
Introduction
The three foramina of the fourth
ventricle of the human brain were
first described during the 19th century.
The primary purpose of this article
was to review the anatomy of the
foramina of the human fourth
ventricle, as well as the main clinical
conditions related to pathology of
these
neurosurgically
important
structures. The existing literature
regarding the gross and neurosurgical
anatomy of the foramina of the human
fourth ventricle was reviewed with
emphasis on the clinical disorders
caused by several pathological
conditions of these structures.
Neuroanatomical comments on the
location of these foramina are also
provided.
Discussion
The fourth ventricle is connected
through the foramen of Magendie with
vallecula cerebelli and cisterna magna,
and laterally through the foramina of
Luschka with the cerebellopontine
angles. The foramen of Magendie is
probably the main path for the
outflow of the cerebrospinal fluid
from the ventricle. The Luschka
foramina are found (at or) above the
pontomedullary junction. The right
Luschka foramen seems to be located
slightly more superior and more
posterior as compared to the left.
Neuroendoscopy offers a detailed
visualisation, particularly of the
structures located in the inferior
triangle of the fourth ventricle. The
main pathological conditions affecting
the foramina of the fourth ventricle
are
usually
associated
with
hydrocephalus
(responsible
for
clinical manifestations) and include
occlusion, membrane obstruction,
congenital imperforation, idiopathic
*Corresponding author
Email: [email protected]
1
Department of Neurology, ‘K.A.T.-N.R.C.’
General Hospital of Attica, Athens, Greece
stenosis, arachnoid adhesions and
cystic dilation.
Conclusion
The foramina of the fourth ventricle,
anatomically
delicate
and
neurosurgically crucial apertures,
have close relations with several
important structures of the brainstem
and cerebellum. Slight differences
seem to exist between the two sides
regarding the location of the Luschka
foramen. Pathological conditions
affecting the foramina of the fourth
ventricle usually produce clinical
manifestations due to obstruction of
the cerebrospinal fluid normal flow.
Microsurgical treatment of such rare
but challenging lesions is nowadays
feasible.
Introduction
The three foramina of the fourth
ventricle of the human brain were
first described during the 19th
century1,2. The foramen of Magendie is
named after the French physiologist
François Magendie (1783-1855) who
is
considered
a
pioneer
of
experimental
physiology1.
The
foramina of Luschka are named after
the German anatomist Hubert von
Luschka (1820-1875) who lent his
name to several structures2.
In 1931, Rogers and West3 described
the anatomy and relations of the
foramen of Magendie, presenting it as
a complete defect in the lower part of
the ventricular roof through which the
fourth
ventricle
is
in
free
communication with the cisterna
magna3. In 1948, Barr4 reported
observations on the foramen of
Magendie in a series of human brains4.
Half century later, Rhoton5 provided
detailed
descriptions
of
the
neurosurgical anatomy of the fourth
ventricle and its foramina5.
The primary purpose of this article
was to review the anatomy of the
foramina of the human fourth
ventricle, as well as the main clinical
conditions related to pathology of these
neurosurgically important structures.
The existing literature regarding the
gross and neurosurgical anatomy of the
foramina of the human fourth ventricle
was reviewed with emphasis on the
clinical disorders caused by several
pathological conditions affecting these
structures. Neuroanatomical comments
on the location of these foramina are
also provided.
Discussion
The author has referenced one of his
own studies in this review. This
referenced study has been conducted in
accordance with the Declaration of
Helsinki (1964) and the protocols of
this study have been approved by the
relevant ethics committees related to
the institution in which it was
performed.
Anatomy and morphometry
The fourth ventricle is a broad, tentshaped midline cavity located between
cerebellum and brainstem. It is
connected rostrally through the
cerebral aqueduct (of Sylvius) with the
third ventricle, caudally with the spinal
canal and through the foramen of
Magendie with vallecula cerebelli (a
cleft between the cerebellar tonsils)
and cisterna magna, and laterally
through the foramina of Luschka with
the cerebellopontine angles. It has a
roof, a floor and two lateral recesses5.
The roof expands laterally and
posteriorly from its narrow rostral end
just below the aqueduct to the level of
the fastigium and lateral recess, the site
of its greatest height and width, and
from there it tapers to a narrow caudal
apex at the level of the foramen of
Magendie5. The floor has a rhomboid
shape. Its cranial apex is at the level of
the cerebral aqueduct; its caudal tip, the
obex, is located at the rostral end of the
remnant of the spinal canal, anterior to
the foramen of Magendie; and its lateral
angles open through the lateral
Licensee OAPL (UK) 2014. Creative Commons Attribution License (CC-BY)
FOR CITATION PURPOSES: Mavridis IN. Clinical anatomy of the fourth ventricle foramina. OA Anatomy 2014 Apr
09;2(1):9.
Competing interests: None declared. Conflict of interests: None declared.
All authors contributed to conception and design, manuscript preparation, read and approved the final manuscript.
All authors abide by the Association for Medical Ethics (AME) ethical rules of disclosure.
IN Mavridis1*
Page 2 of 5
Critical review
The choroid plexus of the fourth
ventricle consists of several segments.
Its lateral segments extend laterally
through the foramina of Luschka
(protruding into the cerebellopontine
angle below the flocculus and behind
the glossopharyngeal, vagus and
accessory nerves) and its medial
segments
extend
longitudinally
through the foramen of Magendie. The
medial segments stretch from the
level of the nodule, anterior to the
cerebellar tonsils, to the level of the
foramen of Magendie. The tonsillar
parts of the choroid plexus are located
anterior to the tonsils and extend
inferiorly through the foramen of
Magendie5.
Ciołkowski et al.6 described the
median aperture (foramen) of
Magendie as the largest of the three
openings of the fourth ventricle and
thus forming the main path for the
outflow of the cerebrospinal fluid
(CSF) from the ventricle. The
Magendie foramen makes a natural
corridor for neurosurgical approach
and inspection of the fourth ventricle
and its floor6. According to the same
authors6, this foramen is limited by
the following structures: obex and
gracile tubercles inferiorly and tela
choroidea with choroid plexus
superolaterally.
Obex
tubercles
usually have the form of a piece of
neural tissue bridging two halves of
the brainstem above the entrance to
the central canal. Gracile tubercles
together are 8.15 mm wide and the
maximal width of the foramen is 6.53
mm. Tela choroidea attaches laterally
at both sides to the inferior medullary
velum. In most cases the right and left
choroid plexuses are connected to
each other with a triangular
membrane of tela choroidea, which
protrudes through the median
foramen and attaches to the vermis at
a highly variable level6.
Sharifi et al.7 studied 40 human
cerebella and distinguished two
compartments of the foramen of
Luschka, namely the choroidal and
patent part. Interestingly, 7.5% of the
foramina were closed. The mean
distance between the foramen of
Luschka and the anterior inferior
cerebellar artery was 3.9 mm. The
distance from the posterior inferior
cerebellar artery was 7.08 and 5.81
mm to the left and right foramina of
Luschka, respectively. In ten cases,
tortuous
vertebral
artery
was
occupying the left cerebellopontine
angle space and the foramen of
Luschka7.
The Magendie foramen is, to the
author’s gross anatomical experience,
located 12 mm (9-15 mm) inferior to
the pontomedullary junction, while
the Luschka foramen is located 1.4
mm (0-11 mm) superior to this
junction. The fourth ventricle extends
≥ 9 mm inferior and the Luschka
foramina are located superior to this
junction (37% placed exactly at this
level). The Magendie foramen is
located 0.3 mm (0-2 mm) posterior to
the fourth ventricle floor, while the
Luschka foramen is located 1.3 mm
(0-4 mm) posterior to this floor (16%
of the Luschka and 83% of the
Magendie foramina were found at the
level of this floor). Interestingly, the
right Luschka foramen seems to be
located 1.5 mm more superior from
the pontomedullary junction and 0.7
mm more posterior from the fourth
ventricle floor as compared to the left.
Longatti et al.8 examined the access to
the fourth ventricle achieved by the
endoscopic transaqueductal approach,
to enumerate and describe the
anatomically identifiable landmarks
and to compare them with those
described
during
microsurgery.
Twenty anatomical structures could
consistently be identified by exploring
the fourth ventricle with a fiberscope,
including the foramina of Luschka and
Magendie. Neuroendoscopy offers a
quite different outlook on the anatomy
of the fourth ventricle, and compared
with the microsurgical descriptions it
seems to provide a superior and
detailed visualisation, particularly of
the structures located in the inferior
triangle8.
Clinical conditions
There
are
several
pathological
conditions of the fourth ventricle
foramina, congenital or acquired, which
usually
cause
hydrocephalus
(principally responsible for clinical
manifestations),
mainly
due
to
obstruction of the normal CSF flow.
Occlusion of the foramen of Magendie
(e.g. by a plexus ependymal cyst) can
cause hydrocephalus9. In children,
occlusion of the foramen of Magendie is
usually the consequence of DandyWalker cysts10 or Arnold-Chiari type I
malformation11. In adults, the occlusion
is rather acquired than congenital,
linked to infection, head trauma,
intraventricular haemorrhage, tumours
or Arnold-Chiari malformation. In rare
cases, in children as well as in adults,
obstructive hydrocephalus has been
reported due to the occlusion of the
foramen of Magendie by a membrane,
likely to be an extension of the inferior
medullary velum and the tela
choroidea. Until now, the diagnosis was
suggested on indirect data, confirmed
by invasive procedures such as
ventriculography or direct surgical
exploration10.
Cystic malformations in the posterior
cranial fossa result from developmental
failure in the paleocerebellum and
meninges12. Takami et al.12 reported a
case of an infant with hydrocephalus
associated with cystic dilation of the
foramina of Magendie and Luschka.
This 7-month-old female infant
presented with sudden onset of tonicclonic seizures. Computed tomography
(CT) scan revealed quadri-ventricular
hydrocephalus. Magnetic resonance
imaging (MRI) demonstrated a cyst
communicating with the fourth
Licensee OAPL (UK) 2014. Creative Commons Attribution License (CC-BY)
FOR CITATION PURPOSES: Mavridis IN. Clinical anatomy of the fourth ventricle foramina. OA Anatomy 2014 Apr
09;2(1):9.
Competing interests: None declared. Conflict of interests: None declared.
All authors contributed to conception and design, manuscript preparation, read and approved the final manuscript.
All authors abide by the Association for Medical Ethics (AME) ethical rules of disclosure.
recesses and foramina of Luschka5.
The foramen of Luschka opens into
the cerebellopontine angle below the
junction
of
the
facial
and
vestibulocochlear nerves with the
lateral end of the pontomedullary
sulcus5. The lateral recesses are
narrow, curved pouches formed by
the union of the roof and the floor.
They extend laterally below the
cerebellar peduncles. The anterior
inferior cerebellar artery is intimately
related to the lateral recess and the
foramen of Luschka5.
Page 3 of 5
Critical review
Three weeks later, however, the
hydrocephalus
recurred.
An
endoscopic
third
ventriculocisternostomy
was
performed to address the possibility
of stagnant CSF flow in the posterior
cranial fossa, but the hydrocephalus
continued.
Finally
the
patient
underwent
placement
of
a
ventriculoperitoneal shunt, resulting
in resolution of the hydrocephalus.
The authors speculated that the cystic
malformation in their patient could be
classified in a continuum of persistent
Blake pouch cysts. Hydrocephalus was
caused by a combination of
obstruction of CSF flow at the outlets
of
the
fourth
ventricle
and
disequilibrium
between
CSF
production and absorption capacity12.
A membrane obstruction of the
foramina of Magendie and Luschka is
an
uncommon
origin
of
hydrocephalus
characterised
by
unusual
clinical
symptoms
of
rhomboid fossa hypertension. Various
surgical approaches have been
proposed to alleviate this obstruction,
including opening the obstructed
foramen
of
Magendie
using
suboccipital craniectomy, shunting
procedures and more recently,
endoscopic third ventriculostomy
(ETV). In some cases, however,
reshaping of the posterior fossa due to
the collapse of the prepontine cistern
could make ETV difficult for the
surgeon and dangerous to the patient.
In these cases, endoscopic opening of
the foramen of Magendie by
transaqueductal navigation of the
fourth ventricle is a suitable and
feasible therapeutic option13.
Rougier and Ménégon10 reported a
case of a 61-year-old man who
developed headaches for several
months and more recently an
unsteady gait. The CT scans showed
quadri-ventricular
hydrocephalus
involving mainly the fourth ventricle
with dilated lateral recesses but
without
an
Arnold-Chiari
malformation. A membrane occluding
the foramen of Magendie was
demonstrated on the MRI. At
operation, the tonsils appeared
normal and were easily separated to
expose the vallecula. In the area of the
foramen of Magendie the fourth
ventricle was hermetically sealed by a
strong membrane in continuation
with the tela choroidea. The
membrane was excised resulting in
free flow of CSF. After surgery, the
headaches resolved immediately
whereas the gait returned to normal
within one month. At six months
following operation, the ventricular
size was normal on the controlled CT
scan10.
Congenital membranous obstruction
of the foramen of Magendie is a rare
entity14. Hashish et al.14 reported two
cases (35 and 68 year-old) with
chronic hydrocephalus due to
congenital membranous obstruction
of the foramen of Magendie. Both
these patients presented with
headaches, nausea, and impairment of
gait and memory. CT and MRI
examination showed a communicating
hydrocephalus,
with
particular
enlargement of the fourth ventricle.
Both patients were operated on for
microsurgical exploration of the outlet
of the fourth ventricle, which
demonstrated
membranous
obstruction of the foramen of
Magendie. Microsurgical perforation
of the foramen of Magendie was
performed, and a ventriculo-cisternal
shunt was left in place. The two
patients were cured14.
Despite its rare occurrence, congenital
imperforation
or
membranous
obstruction of the foramen of Magendie
must be considered as a possible
etiology of chronic hydrocephalus in
adult, especially in case of non
proportioned enlargement of the fourth
ventricle, associated to signs of
increased
intracranial
pressure14.
According to Hashish et al.14, the best
curative surgical procedure consists in
a microsurgical exploration of the
foramen of Magendie associated to a
ventriculo-cisternal shunting (from the
fourth ventricle to the cisterna magna)
and has more advantages than a simple
ventriculo-peritoneal shunting14.
Tubbs15 reported a young girl who
presented with headache and back
pain. Dynamic MRI revealed no
cerebrospinal egress from the median
aperture (foramen of Magendie) of the
fourth ventricle and syringomyelia. A
posterior cranial fossa exploration was
performed and agenesis of the median
aperture was observed. Following
surgical penetration of the posterior
aspect of the fourth ventricle and at the
most recent follow-up examination, this
patient's syringomyelia had resolved, as
had her symptoms. Agenesis of the
foramen of Magendie may be a rare
cause of inhibition of normal CSF egress
from the fourth ventricle with resultant
syringomyelia15.
Idiopathic stenosis of the foramina of
Magendie and Luschka is a rare cause of
obstructive hydrocephalus involving
the four ventricles. Like other causes of
non-communicating hydrocephalus, it
can be treated with ETV16. Karachi et
al.16 reported three patients (21, 53 and
68 years of age) presenting with either
headaches (with or without raised
intracranial pressure) or vertigo, or a
combination of gait disorders, sphincter
disorders and disorders of higher
functions.
In
each
case,
MRI
demonstrated hydrocephalus involving
the four ventricles with no signs of an
Arnold-Chiari type I malformation. The
diagnosis of obstruction was confirmed
using ventriculography and/or MR flow
images. All patients presented with
marked dilation of the foramen of
Luschka that herniated into the cisterna
pontis. All patients were
Licensee OAPL (UK) 2014. Creative Commons Attribution License (CC-BY)
FOR CITATION PURPOSES: Mavridis IN. Clinical anatomy of the fourth ventricle foramina. OA Anatomy 2014 Apr
09;2(1):9.
Competing interests: None declared. Conflict of interests: None declared.
All authors contributed to conception and design, manuscript preparation, read and approved the final manuscript.
All authors abide by the Association for Medical Ethics (AME) ethical rules of disclosure.
ventricle and projecting to the
cisterna
magna
and
the
cerebellopontine cisterns through the
foramina of Magendie and Luschka. A
suboccipital
craniotomy
was
performed for removal of the cyst wall
and the transparent membrane
covering the foramen of Magendie
was removed under a microscope.
After the surgery, the patient's
hydrocephalus improved and a phase
contrast cine MRI study showed
evidence of normal CSF flow at the
level of the third and fourth ventricles.
Page 4 of 5
Critical review
Finally, Rahme et al.17 reported a
unique case of a 38-year-old male
with cervical syringomyelia resulting
from spontaneous regeneration of the
posterior C1 arch three years after
foramen magnum decompression.
Neo-ossification of the posterior arch
of C1 and thick arachnoid adhesions
were found to obstruct cerebrospinal
fluid flow through the foramen of
Magendie.
Foramen
magnum
decompression, arachnoid dissection
and duraplasty were thus performed
and CSF flow was reestablished
through the foramen of Magendie17.
Table 1 summarises the main
pathological conditions affecting the
foramina of the fourth ventricle.
Conclusion
The foramina of the fourth ventricle
(Figure 1) are anatomically delicate
and
neurosurgically
(neuroendoscopically) crucial parts of
the ventricular system of the brain.
They have close relations with several
important structures of the brainstem
and cerebellum. Slight differences
seem to exist between the two sides
regarding the location of the Luschka
foramen. Pathological conditions
affecting the foramina of the fourth
ventricle (congenital or acquired)
usually
produce
clinical
manifestations due to obstruction of
the normal flow of the CSF.
Microsurgical treatment of such rare
but challenging lesions is nowadays
feasible.
Table 1: Main pathological conditions affecting the foramina of the fourth
ventricle
1
Occlusion (e.g. infection, head trauma, intraventricular haemorrhage,spaceoccupying lesions, congenital anomalies)
2
Membrane obstruction
3
Congenital imperforation (agenesis)
4
Idiopathic stenosis
5
Arachnoid adhesions
6
Cystic dilation
Figure 1: The location of the foramina of the fourth ventricle (human brain, right hemisphere,
fourth ventricle area). 1: arbour vitae, 2: posterior commissure, 3: cerebellar tonsil, 4: lingula,
5: midbrain, 6: superior medullary velum, 7: quadrigeminal cistern (of the great cerebral
vein), 8: roof of the fourth ventricle, 9: cerebral aqueduct (of Sylvius), 10: pons, 11: fourth
ventricle, 12: cerebellar hemisphere, L: right foramen of Luschka, M: foramen of Magendie
18
(line: intercommissural line) (modified from Mavridis ).
Abbreviations list
CSF, cerebrospinal fluid; CT, computed
tomography; ETV, endoscopic third
ventriculostomy;
MRI,
magnetic
resonance imaging.
References
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François Magendie. Available from:
http:en.wikipedia.org/wiki/Fran%C3
%A7ois_Magendie; 2014 [accessed 5
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Luschka.
Available
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Licensee OAPL (UK) 2014. Creative Commons Attribution License (CC-BY)
FOR CITATION PURPOSES: Mavridis IN. Clinical anatomy of the fourth ventricle foramina. OA Anatomy 2014 Apr
09;2(1):9.
Competing interests: None declared. Conflict of interests: None declared.
All authors contributed to conception and design, manuscript preparation, read and approved the final manuscript.
All authors abide by the Association for Medical Ethics (AME) ethical rules of disclosure.
uncomplicatedly treated using ETV,
became asymptomatic within weeks
following surgery and remained stable
at a mean follow-up interval of 36
months.
Postoperative
MRIs
demonstrated regression of the
hydrocephalus, resolution of dilation
of the foramen of Luschka and good
patency of the ventriculostomy (flow
sequences). These results confirm the
existence of hydrocephalus caused by
idiopathic fourth ventricle outflow
obstruction without an associated
Arnold-Chiari type I malformation and
the efficacy of ETV for this rare
indication16.
Page 5 of 5
Critical review
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IN.
[Stereotactic
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accumbens]. PhD Thesis, National and
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Licensee OAPL (UK) 2014. Creative Commons Attribution License (CC-BY)
FOR CITATION PURPOSES: Mavridis IN. Clinical anatomy of the fourth ventricle foramina. OA Anatomy 2014 Apr
09;2(1):9.
Competing interests: None declared. Conflict of interests: None declared.
All authors contributed to conception and design, manuscript preparation, read and approved the final manuscript.
All authors abide by the Association for Medical Ethics (AME) ethical rules of disclosure.
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P, Melon E, Decq P. Hydrocephalus
due to idiopathic stenosis of the