Download Anatomy of the posterior fossa emissary veins and their clinical

Anatomy of the posterior fossa emissary veins and their
clinical importance
Poster No.:
C-1752
Congress:
ECR 2013
Type:
Educational Exhibit
Authors:
R. Pekcevik, Y. Pekcevik; Izmir/TR
Keywords:
Computer Applications-Detection, diagnosis, MR-Angiography,
CT-High Resolution, CT-Angiography, Head and neck, Congenital
DOI:
10.1594/ecr2013/C-1752
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Learning objectives
1) To review and simplify the complex anatomy of the posterior fossa emissary veins.
2) To describe their anatomy using high resolution CT, CT angiography and MR
venography images.
3) To discuss clinical importance of reporting these vascular variants.
Background
An emissary (Latin emissarium, from ex and mittere, to send out) is a channel, natural or
artificial, by which an outlet is formed to carry off any stagnant body of water (Figure 1).
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Fig. 1: Ephesus, Izmir, Turkey. The ancient Romans excelled in the construction of
emissaries, as in all their hydraulic works. This is the Roman communal bathroom.
Water running underneath the toilets and there is a channel in front, that had running
water for washing up after.
References: - Izmir/TR
Mastoid emissary vein (MEV), condylar emissary veins and petrosquamosal sinus
(PSS) are valveless veins which pass through cranial apertures. They participate in the
extracranial venous drainage of posterior fossa dural sinuses. They protect the brain
from increases of the intracranial pressure. Emissary veins also help to cool venous
blood circulating through cephalic structures (1,2). They may be associated with inner
ear malformations and craniofacial syndromes (1-3).
Images for this section:
Fig. 1: Ephesus, Izmir, Turkey. The ancient Romans excelled in the construction of
emissaries, as in all their hydraulic works. This is the Roman communal bathroom. Water
running underneath the toilets and there is a channel in front, that had running water for
washing up after.
Page 3 of 43
Imaging findings OR Procedure details
Embryology
The major cerebral venous outflow pathways are the internal jugular veins (IJV) and the
vertebral venous system (VVS). Internal jugular vein is dominant in the supine position
and transfer of the IJV outflow to the VVS when standing upright (3).
External juguler veins (EJV) predominantly drain the viscerocranium and the
neurocranium and their participation in the cerebral venous drainage is limited (4).
Development of the intracerebral veins and their extracranial drainage is complex in
humans. The primary capillary plexus of the early embryo develops in three layers. The
superficial vessels drain into the external jugular vein; the middle and deep vessels drain
into the internal jugular vein. Emissary veins, in the third trimester, consist of residual
connections between the superficial and middle layers (4,5).
In humans, the venous drainage of the posterior fossa has frequent anatomical variations.
Most variations involving the lateral sinus in humans allow conservation of the IJV and
VVS as their major outflow pathways. Only rarely, when the sigmoid sinus is absent
or severely hypoplastic, may a petrosquamosal sinus, mastoid emissary or posterior
condylar emissary vein represent the major or only drainage pathway of the transverse
sinus (4, 6).
Anatomy
Mastoid emissary vein
Mastoid emissary vein crosses the mastoid foramen (Figure 2) and runs between
sigmoid sinus and the posterior auricular or the occipital vein. The the posterior
auricular and the occipital vein drains into suboccipital venous plexus or internal jugular
vein (Figure 3-5). The suboccipital venous plexus is located above the splenius capitis
muscle and pass through a cleft between the semispinalis and longissimus capitis muscle
and drains anterior vertebral vein or deep cervical vein (3, 7). (Figure 6)
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Fig. 2: Mastoid foramina. 3D VR, CTA posterior view show one foramen on the left,
two foramina on the right side.
References: - Izmir/TR
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Fig. 3: Oblique MPR CTA images show mastoid emissary canal and vein (long
arrow) that runs between sigmoid sinus (S) and the posterior auricular vein (double
arrows)and then suboccipital venous plexus (white arrow).
References: - Izmir/TR
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Fig. 4: 3D VR CTA lateral view show the mastoid emissary foramen and vein (black
arrow) that drain into posterior auricular vein (double arrows) and then suboccipital
venous plexus (white arrow).
References: - Izmir/TR
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Fig. 5: 3D VR CTA posterior view show the mastoid emissary foramen and vein (black
arrow) that drain into posterior auricular vein (double arrows) and then suboccipital
venous plexus (white arrow). Occiptal vein (arrowhead).
References: - Izmir/TR
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Fig. 6: 3D PCA MR venography shows the suboccipital venous plexus that is located
above the splenius capitis muscle (rectangular), pass through a cleft between the
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semispinalis (ellipse) and longissimus (trianguler) capitis muscle and drains into deep
cervical vein (arrow).
References: - Izmir/TR
Emissary condylar veins
Emissary condylar veins are divided into three groups as posterior, lateral and anterior
condylar veins (3,7).
The posterior condylar vein usually took its origin from the superior bulb of the
internal jugular vein. It courses along the posterior condylar vein canal, emerges from
its foramen (Figure 7) and drains into the deep cervical vein. It has connection with the
horizontal portion of the vertebral artery venous plexus (Figure 8-10).
The lateral condylar vein generally orginates from a venous network near internal juguler
vein and then drains into vertebral venous system (Figure 15). The anterior condylar vein
appeared as a plexiform connection of the anterior internal vertebral venous plexus with
the internal jugular vein.
Fig. 7: 3D VR CTA posterior view show bilateral condylar foramen (arrows).
References: - Izmir/TR
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Fig. 8: Axial MPR CTA images show posterior condylar emissary canal and vein
(arrows.
References: - Izmir/TR
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Fig. 9: Ssagittal oblique MPR CTA images show posterior condylar emissary canal
and vein (arrows).
References: - Izmir/TR
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Fig. 10: 3D VR CTA lateral oblique view show the posterior condylar emissary
foramen (arrowhead). Posterior condylar vein drain into the deep cervical vein (arrows)
and vertebral plexus around the horizontal portion of the vertebral artery (double
arrows).
References: - Izmir/TR
Occipiatal emissary vein
Occipital emissary vein connects the transvers sinuses near the confluens sinuum region
to the suboccipital plexus (3, 7) (Figure 11,12).
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Fig. 11: 3D VR CTA posterior view shows occipital emissary vein foramina (arrows).
References: - Izmir/TR
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Fig. 12: Sagittal MPR CTA images (the same patient as in Fig. 11) shows occipital
emissary vein canal and vein (arrows)that connects the confluens sinuum to the
occipital vein.
References: - Izmir/TR
Petrosquamosal sinus
Petrosquamosal sinus (PSS) arises from the transverse sinus before its confluence with
the superior petrosal sinus and drains either into the retromandibular vein through the
postglenoid foramen (PGF) or into the pterygoid venous plexus through the foramen
ovale (4, 5). The external jugular vein (EJV) is the main drainage pathway of the PSS
(Figure 13-15).
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Fig. 13: Axial HRCT image shows a sulcus (white arrow), originating from the anterior
portion of the transverse sinus and passing anteriorly through the lateral portion of the
petrous bone.
References: - Izmir/TR
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Fig. 14: Sagittal reformatted CT image shows the PSS ending in the postglenoid
foramen (white arrow). The black arrow indicates is mastoid emissary canal.
References: - Izmir/TR
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Fig. 15: 3D PCA MRV, right posterolateral oblique MIP image shows the right mastoid
emissary vein (arrow) draining into large occipital vein, suboccipital venous plexus and
then deep cervical vein. Posterior condylar vein (double arrows), ascends from the
superior bulb of the internal jugular vein to the deep cervical vein. Lateral condylar vein
(small arrowhead) takes its origin from internal juguler vein and connected with the
vertebral artery venous plexus. Large arrowhead shows the petrosquamosal sinus, (the
same patient as in Fig. 8).
References: - Izmir/TR
Clinical significance
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Diagnosis and describing PSS, MEV and other emmissary veins is very important
because:
-Emissary veins are associated with inner ear malformations and syndromic
craniosynostosis (1,6,9)
-They are potential source of intense bleeding and air or surgical material embolism
during surgical procedures (2,3,7).
-They can be the source of thrombosis in the sigmoid sinus occurring after middle ear
surgery or of a retrograde, thrombophlebitic extension from an infected mastoid cavity
(5,10).
- Emissary veins can become may represent the main outflow pathway of the transverse
sinus in some cases. Particular care should be taken during surgical procedures, as
the sacrifice of this outflow pathway could lead to catastrophic venous ischemic and
hemorrhagic consequences (1,3) (Figure 16).
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Fig. 16: Mastoid emissary vein is originating from sigmoid sinus (S) and draining into
the external jugular vein.
References: - Izmir/TR
- They may be enlarged due to jugular vein trombosis and mentioning this preoperatively
may change the surgical approach (Figure 17)
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Fig. 17: 3D VR CTA posterior view shows enlarged posterior condylar vein, deep
cervical vein and vertebral venous plexus due to right jugular vein trombosis (arrows).
References: - Izmir/TR
-They may have close relationship with the skull base or neck tumors (Figure 18)
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Fig. 18: Sagittal MIP CTA shows hypervascular neck lesion that has close relationship
with posterior condylar vein (arrow).
References: - Izmir/TR
-The diameter of the MEV may be important that this vessel could be a potential target for
cannulation during endovascular procedures involving the transverse or sigmoid sinus
(3,12). Endovascular treatment of dural arteriovenous fistulas can be done via large
mastoid emissary vein(7).
Images for this section:
Fig. 2: Mastoid foramina. 3D VR, CTA posterior view show one foramen on the left, two
foramina on the right side.
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Fig. 3: Oblique MPR CTA images show mastoid emissary canal and vein (long arrow)
that runs between sigmoid sinus (S) and the posterior auricular vein (double arrows)and
then suboccipital venous plexus (white arrow).
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Fig. 4: 3D VR CTA lateral view show the mastoid emissary foramen and vein (black
arrow) that drain into posterior auricular vein (double arrows) and then suboccipital
venous plexus (white arrow).
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Fig. 5: 3D VR CTA posterior view show the mastoid emissary foramen and vein (black
arrow) that drain into posterior auricular vein (double arrows) and then suboccipital
venous plexus (white arrow). Occiptal vein (arrowhead).
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Fig. 6: 3D PCA MR venography shows the suboccipital venous plexus that is located
above the splenius capitis muscle (rectangular), pass through a cleft between the
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semispinalis (ellipse) and longissimus (trianguler) capitis muscle and drains into deep
cervical vein (arrow).
Fig. 7: 3D VR CTA posterior view show bilateral condylar foramen (arrows).
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Fig. 8: Axial MPR CTA images show posterior condylar emissary canal and vein (arrows.
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Fig. 9: Ssagittal oblique MPR CTA images show posterior condylar emissary canal and
vein (arrows).
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Fig. 10: 3D VR CTA lateral oblique view show the posterior condylar emissary foramen
(arrowhead). Posterior condylar vein drain into the deep cervical vein (arrows) and
vertebral plexus around the horizontal portion of the vertebral artery (double arrows).
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Fig. 11: 3D VR CTA posterior view shows occipital emissary vein foramina (arrows).
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Fig. 12: Sagittal MPR CTA images (the same patient as in Fig. 11) shows occipital
emissary vein canal and vein (arrows)that connects the confluens sinuum to the occipital
vein.
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Fig. 13: Axial HRCT image shows a sulcus (white arrow), originating from the anterior
portion of the transverse sinus and passing anteriorly through the lateral portion of the
petrous bone.
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Fig. 14: Sagittal reformatted CT image shows the PSS ending in the postglenoid foramen
(white arrow). The black arrow indicates is mastoid emissary canal.
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Fig. 15: 3D PCA MRV, right posterolateral oblique MIP image shows the right mastoid
emissary vein (arrow) draining into large occipital vein, suboccipital venous plexus and
then deep cervical vein. Posterior condylar vein (double arrows), ascends from the
superior bulb of the internal jugular vein to the deep cervical vein. Lateral condylar vein
(small arrowhead) takes its origin from internal juguler vein and connected with the
vertebral artery venous plexus. Large arrowhead shows the petrosquamosal sinus, (the
same patient as in Fig. 8).
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Fig. 16: Mastoid emissary vein is originating from sigmoid sinus (S) and draining into the
external jugular vein.
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Fig. 17: 3D VR CTA posterior view shows enlarged posterior condylar vein, deep cervical
vein and vertebral venous plexus due to right jugular vein trombosis (arrows).
Fig. 18: Sagittal MIP CTA shows hypervascular neck lesion that has close relationship
with posterior condylar vein (arrow).
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Conclusion
We believe that posterior fossa emissary veins can be detected by radiologist before
surgery with thorough understanding of their anatomy. Describing them in temporal bone
CT, CT angiography and cerebral MR venography examinations result in more detailed
and accurate preoperative radiological interpretation and have clinical importance.
References
1. Louis RG Jr, Loukas M, Wartmann CT, Tubbs RS, Apaydin N, Gupta AA, t al. Clinical
anatomy of the mastoid and occipital emissary veins in a large series. Surg Radiol Anat
2009;31:139-44.
2. Hadeishi H, Yasui N, Suzuki A. Mastoid canal and migrated bone wax in the sigmoid
sinus: technical report. Neurosurgery 1995;36:1220-23.
3. Reis CV, Deshmukh V, Zabramski JM, Crusius M, Desmukh P, Spetzler RF, et al.
Anatomy of the mastoid emissary vein and venous system of the posterior neck region:
neurosurgical implications. Neurosurgery 2007;61:193-200.
4. San Millán Ruíz D, Gailloud P, Rüfenacht DA, Delavelle J, Henry F, Fasel JH.
The craniocervical venous system in relation to cerebral venous drainage. AJNR Am J
Neuroradiol 2002;23:1500-8.
5. Marsot-Dupuch K, Gayet-Delacroix M, Elmaleh-Bergès M, Bonneville F, Lasjaunias
P. The petrosquamosal sinus: CT and MR findings of a rare emissary vein. AJNR Am J
Neuroradiol 2001;22:1186-93.
6. Giesemann AM, Goetz GF, Neuburger J, Lenarz T, Lanfermann H. Persistent
petrosquamosal sinus: high incidence in cases of complete aplasia of the semicircular
canals. Radiology 2011;259:825-33.
7. Jeevan DS, Anlsow P, Jayamohan J. Abnormal venous drainage in syndromic
craniosynostosis and the role of CT venography. Childs Nerv Syst. 2008
Dec;24(12):1413-20.
8. Chauhan NS, Sharma YP, Bhagra T, Sud B. Persistence of multiple emissary veins of
posterior fossa with unusual origin of left petrosquamosal sinus from mastoid emissary.
Surg Radiol Anat 2011;33:827-31.
Page 42 of 43
9. Morimoto AK, Wiggins RH 3rd, Hudgins PA, Hedlund GL, Hamilton B, Mukherji SK,
et al. Absent semicircular canals in CHARGE syndrome: radiologic spectrum of findings.
AJNR Am J Neuroradiol 2006;27:1663-71.
10. An YH, Wee JH, Han KH, Kim YH. Two cases of petrosquamosal sinus in the temporal
bone presented as perioperative finding. Laryngoscope 2011;121:381-4.
11. San Millán Ruíz D, Gailloud P, Yilmaz H, Perren F, Rathgeb JP, Rüfenacht DA, et al.
The petrosquamosal sinus in humans. J Anat 2006;209:711-20.
12. Koesling S, Kunkel P, Schul T. Vascular anomalies, sutures and small canals of the
temporal bone on axial CT. Eur J Radiol 2005;54:335-43.
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