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AJR 2001; 176:1059-1065
© American Roentgen Ray Society


Pictorial Essay

Topographic Anatomy of the Vertebral Venous System in the Thoracic Inlet

Kenji Ibukuro1, Hozumi Fukuda, Koichi Mori and Yoshihiro Inoue

1 All authors: Department of Radiology, Mitsui Memorial Hospital, 1-Kanda Izumicho Chiyoda-ku, Tokyo 101-8643, Japan.

Received August 14, 2000; accepted after revision September 15, 2000.

 
Address correspondence to K. Ibukuro.


Introduction
Top
Introduction
Vertebral Veins
Perivertebral Venous Plexuses
Communications Between Vertebral...
Clinical Significance
References
 
The vertebral venous system in the thoracic inlet consists of the vertebral veins and perivertebral venous plexuses such as the anterior and posterior external plexuses and the internal plexus. Metastatic tumors can appear in locations that do not seem to be in the line of direct spread from their primary focus, which is called paradoxical metastasis. The vertebral venous system is well known as the pathway of paradoxical metastasis, as in bone metastases in patients with prostate cancer and breast cancer, which was reported by Batson [1] on the basis of cadaver and animal injection experiments in 1940. Anderson [2] proved that contrast material backs up into the deep cervical veins, and that the vertebral venous system is shown on upper extremity venography when intrathoracic pressure is elevated, as during Valsalva's maneuver. The clinical significance of the vertebral venous system as collateral vessels is also recognized in patients with upper extremity venous thrombosis [3] and various other conditions [4].

In this pictorial essay, we illustrate the topographic anatomy of the vertebral venous system in the thoracic inlet as shown on CT scans in patients with venous stenosis and in cadaver dissections (Fig. 1A,1B). We describe the clinical significance of recognizing this venous system.



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Fig. 1A. Diagrams of vertebral venous system in thoracic inlet. Anterior view. Az = azygos vein, EDV = epidural venous plexus, DCV = deep cervical vein, IVV = intervertebral vein, LBCV = left brachiocephalic vein, LPV = longitudinal prevertebral vein, RSICV = right superior intercostal vein, VV = vertebral vein, ICV = intercostal vein. Asterisk indicates esophageal veins, dotted line indicates peripheral branches of deep cervical vein in back neck.

 


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Fig. 1B. Diagrams of vertebral venous system in thoracic inlet. Axial view. A = anterior epidural venous plexus, B = basivertebral veins, C = musculus longissimus colli, D = deep cervical veins, I = intervertebral veins, L = longitudinal prevertebral veins, P = posterior epidural venous plexus, S = musculus semispinalis cervicis, V = vertebral veins.

 


Vertebral Veins
Top
Introduction
Vertebral Veins
Perivertebral Venous Plexuses
Communications Between Vertebral...
Clinical Significance
References
 
The cervical vertebral vein accompanies the vertebral artery in the transverse process foramen in the upper cervical vertebrae, emerges from the transverse process foramen of the sixth cervical vertebra, joins the deep cervical vein [5], descends laterally, then drains into the upper portion of the brachiocephalic vein.

The cervical vertebral vein is a U- or ring-shaped structure surrounding the vertebral artery in the transverse process foramen of the upper cervical vertebrae [6]. The vertebral vein below the level of the sixth cervical vertebra is seen as a round opacification adjacent to the vertebral artery located anterolateral to the musculus longissimus colli on contrast-enhanced CT (Figs. 1B and 2A,2B,2C).



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Fig. 2A. Vertebral veins in 70-year-old woman with bladder cancer. Transverse contrast-enhanced CT scans of neck show vertebral arteries (A, arrowheads) and vertebral veins (V, short arrows). Internal jugular veins (asterisks), common carotid arteries (stars), and subclavian arteries (SC, long arrows, B and C) are also seen.

 


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Fig. 2B. Vertebral veins in 70-year-old woman with bladder cancer. Transverse contrast-enhanced CT scans of neck show vertebral arteries (A, arrowheads) and vertebral veins (V, short arrows). Internal jugular veins (asterisks), common carotid arteries (stars), and subclavian arteries (SC, long arrows, B and C) are also seen.

 


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Fig. 2C. Vertebral veins in 70-year-old woman with bladder cancer. Transverse contrast-enhanced CT scans of neck show vertebral arteries (A, arrowheads) and vertebral veins (V, short arrows). Internal jugular veins (asterisks), common carotid arteries (stars), and subclavian arteries (SC, long arrows, B and C) are also seen.

 


Perivertebral Venous Plexuses
Top
Introduction
Vertebral Veins
Perivertebral Venous Plexuses
Communications Between Vertebral...
Clinical Significance
References
 
Perivertebral venous plexuses in and around the lower cervical and upper thoracic vertebrae are classified as four plexuses on the basis of location: anterior external plexus (longitudinal prevertebral veins), internal plexus (epidural venous plexus), posterior external plexus (deep cervical and posterior intercostal veins), and basivertebral veins (Fig. 1A,1B). These plexuses communicate with each other, and the blood flow can reverse. In addition, anastomoses exist between the vertebral venous system and the azygos and esophageal veins.

Anterior External Plexus (Longitudinal Prevertebral Vein)
Two longitudinal prevertebral veins are located medially to the musculus longissimus colli on the anterior surface of the cervical vertebrae and anastomose with the vertebral veins on each side. Both longitudinal prevertebral veins are united with segmental transverse anastomoses [7]; therefore, there are stepladderlike anastomoses between the bilateral vertebral veins at the anterior aspect of the cervical vertebrae (Fig. 3A,3B,3C,3D). The longitudinal prevertebral veins are seen as two opacified dots in front of the cervical vertebrae on contrast-enhanced CT (Fig. 4A,4B).



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Fig. 3A. Photographs of dissection of perivertebral venous plexus in cadaver of 80-year-old with no evidence of neck or chest disease. Anterior view. Trachea, pharynx, and surrounding soft tissue have been removed. Right and left longitudinal prevertebral veins (stars) are located medially to musculus longissimus colli (L) and in front of cervical vertebrae. Anastomosis (arrowheads) between bilateral longitudinal prevertebral veins and anastomoses (long thick arrows) between longitudinal prevertebral and vertebral veins (V) are identified. Caudal portion of right (short arrow) and left (long thin arrow) longitudinal prevertebral veins communicate with right superior intercostal vein (SIC) and esophageal vein (E), respectively. D = deep cervical vein, A = vertebral artery.

 


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Fig. 3B. Photographs of dissection of perivertebral venous plexus in cadaver of 80-year-old with no evidence of neck or chest disease. Posterior view. musculus trapezius, musculus semispinalis capitis, musculus splenius cervicis and capitis, and musculus longissimus cervicis have been removed. Peripheral branches (arrows) and trunk (arrowheads) of deep cervical veins are seen on surface of musculus semispinalis cervicis. Bilateral peripheral branches of deep cervical veins are anastomosed around spinous process of cervical vertebrae.

 


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Fig. 3C. Photographs of dissection of perivertebral venous plexus in cadaver of 80-year-old with no evidence of neck or chest disease. View from right. Right lung and part of right brachiocephalic artery and vein have been removed. Esophagotracheal vein (arrowheads) is identified at right aspect of trachea (T), which drains into posterior aspect of right brachiocephalic vein. Anastomoses (long arrow) between right longitudinal prevertebral vein (LP) and right superior intercostal vein (SIC, short arrow) are seen. A = azygos vein.

 


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Fig. 3D. Photographs of dissection of perivertebral venous plexus in cadaver of 80-year-old with no evidence of neck or chest disease. View from left. Aortic arch has been removed. Two branches of left longitudinal prevertebral veins (arrows) enter posterior aspect of upper esophagus (E). S = left superior intercostal vein.

 


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Fig. 4A. Longitudinal prevertebral veins in 72-year-old man with left brachiocephalic vein obstruction after left upper lobectomy because of lung cancer. Transverse contrast-enhanced CT scan shows anastomosis (black arrow) between two longitudinal prevertebral veins behind esophagus. Anastomosis (white arrow) between right vertebral vein (V, arrowhead) and longitudinal prevertebral vein is also noted.

 


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Fig. 4B. Longitudinal prevertebral veins in 72-year-old man with left brachiocephalic vein obstruction after left upper lobectomy because of lung cancer. Transverse contrast-enhanced CT scan obtained 1 cm below A shows longitudinal prevertebral veins (LP, arrows).

 

Internal Plexus (Epidural Venous Plexus)
The anterior and posterior epidural venous plexuses are in the spinal canal; however, the anterior half is much larger and more regular than the posterior half [8]. The bilateral vertebral veins are united with the epidural venous plexus (Fig. 5) via the intervertebral veins, in which the blood flow may be reversed.



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Fig. 5. Photograph shows dissection (viewed from back) of anterior epidural venous plexus in cadaver of 68-year-old with no evidence of neck and chest disease. Back neck muscle and all of arches of cervical vertebrae have been removed. Anterior epidural venous plexuses (asterisks) are seen at posterior surface of cervical vertebral body and lateral to posterior longitudinal ligament. Anterior epidural venous plexuses anastomose vertebral vein through intervertebral vein (arrow).

 

The anterior epidural venous plexus is seen as a high-density band at the posterior aspect of the vertebral body on contrast-enhanced CT (Fig. 6). Compared with the anterior epidural venous plexus, the posterior half is rarely seen. Russell et al. [6] showed that visualization of the posterior displacement of the enhanced epidural veins provides excellent delineation of disk extrusion on contrast-enhanced CT.



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Fig. 6. Anterior epidural venous plexus in 67-year-old man with left upper lobectomy because of lung cancer. Transverse contrast-enhanced CT scan shows anterior epidural venous plexus (arrow) located at anterior aspect of spinal canal, through which right and left vertebral veins anastomose. Note no evidence of opacification of venous plexus located at posterior aspect of spinal canal.

 

Posterior External Plexus (Deep Cervical and Posterior Intercostal Veins)
The deep cervical vein receives tributaries from the deep muscles at the back of the neck, runs forward above the neck of the first rib, and terminates in the lower part of the vertebral vein [5]. The bilateral deep cervical veins are united with each other via the plexuses around the spinous process of the cervical vertebrae (Fig. 3A,3B,3C,3D) and also anastomose with the posterior intercostal vein. Therefore, those veins form a venous plexus on the posterior surface of the laminae and the spinous and transverse processes of vertebrae.

The posterior external plexus is seen as a Y-shaped opacification at the posterior aspect of the arch of vertebrae on contrast-enhanced CT (Fig. 7).



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Fig. 7. Posterior external plexus in 66-year-old man with prostate cancer. Transverse contrast-enhanced CT scan shows posterior external plexus as Y-shaped opacification (arrow) around spinous process of vertebrae.

 

Basivertebral Veins
Basivertebral veins are tortuous vascular channels in the vertebral bodies and unite with the longitudinal prevertebral veins and the anterior epidural venous plexus. Basivertebral veins are seen as high-density streaks between the longitudinal prevertebral veins and the anterior epidural venous plexus in the vertebral body on contrast-enhanced CT (Fig. 8).



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Fig. 8. Basivertebral vein in 70-year-old man with stenosis of left brachiocephalic vein resulting from aortic arch aneurysm. Transverse contrast-enhanced CT scan shows basivertebral vein (arrowheads) through which right longitudinal prevertebral vein (LP, white arrow) located behind esophagus anastomoses anterior epidural venous plexus (AE, black arrow). Bilateral vertebral veins (asterisks) running posteriorly from brachiocephalic veins are well opacified.

 


Communications Between Vertebral Venous System and Systemic Veins
Top
Introduction
Vertebral Veins
Perivertebral Venous Plexuses
Communications Between Vertebral...
Clinical Significance
References
 
Longitudinal Prevertebral Vein and Azygos System
The longitudinal prevertebral vein runs downward and unites with the azygos venous system via the superior intercostal vein in the upper thorax (Figs. 3A,3B,3C,3D and 9A,9B).



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Fig. 9A. Bilateral superior intercostal veins in 54-year-old woman with left upper lobectomy because of lung cancer. Transverse contrast-enhanced CT scan shows opacified left longitudinal prevertebral vein (LP, thick white arrow). Bilateral superior intercostal veins (SIC, thin white arrows) are opacified via epidural venous plexus (AE, arrowheads) and intervertebral veins (IV, black arrows).

 


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Fig. 9B. Bilateral superior intercostal veins in 54-year-old woman with left upper lobectomy because of lung cancer. Transverse contrast-enhanced CT scan obtained 2 cm below A shows right superior intercostal vein (RSIC, thick white arrow) running forward to join azygos vein and left longitudinal prevertebral vein uniting with left superior intercostal vein (LSIC, thin white arrow). AE and arrowheads indicate anterior epidural venous plexus.

 

Longitudinal Prevertebral Vein and Esophageal Vein
The longitudinal prevertebral vein sometimes unites with the veins of the upper esophagus (Fig. 3A,3B,3C,3D). This pathway is not usually seen on contrast-enhanced CT; however, it plays an important role in "downhill" varices, which we will soon describe, in patients with superior vena cava syndrome.

Epidural Venous Plexus and Azygos System
In the upper thorax, the epidural venous plexuses are anastomosed with the superior intercostal veins via the intervertebral veins. Therefore, the blood of the neck and upper extremities can run downward in the epidural venous plexuses, reach the superior intercostal vein, and then drain into the azygos vein (Fig. 9A,9B).


Clinical Significance
Top
Introduction
Vertebral Veins
Perivertebral Venous Plexuses
Communications Between Vertebral...
Clinical Significance
References
 
Although the vertebral venous system may not consist of principal collaterals, it is useful to know its existence for analyzing venograms and CT images.

Collateral Pathways in Upper Extremity Venous Thrombosis
Four potential collateral pathways bypass the axillary—subclavian vein region [3]: shoulder to chest wall, shoulder to ipsilateral anterior neck, shoulder to ipsilateral posterior neck, and shoulder to contralateral neck. The vertebral venous system plays an important role in the pathways of shoulder to ipsilateral posterior neck and shoulder to contralateral neck.

Ipsilateral Posterior Neck Pathway
Collateral pathways tend to develop in the intramuscular venous network in the posterior neck, and those veins reconstitute the vertebral vein (Fig. 10A,10B).



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Fig. 10A. Ipsilateral posterior neck pathway in 54-year-old woman with spontaneous thrombosis of axillary vein termed "effort thrombosis." Right upper extremity venogram shows that right axillary vein (Ax, arrowhead) is thrombosed and that contrast material runs forward to posterior neck and reconstitutes right vertebral vein (V, straight arrow) via veins of posterior neck. Right vertebral vein empties into brachiocephalic vein distal to obstruction. Anterior jugular arch (Aj, curved arrow) is also opacified.

 


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Fig. 10B. Ipsilateral posterior neck pathway in 54-year-old woman with spontaneous thrombosis of axillary vein termed "effort thrombosis." Transverse contrast-enhanced CT scan shows opacified right vertebral vein (V, arrow) located at right aspect of trachea (T). Note right brachiocephalic vein (BC, arrowhead) is located anterolateral to right vertebral vein.

 

Contralateral Neck Pathway
Although the most prominent neck pathway is the jugular venous arch connecting the bilateral anterior jugular veins in the suprasternal space, the contralateral vertebral vein is also opacified through the perivertebral venous plexuses (Fig. 11A,11B).



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Fig. 11A. Contralateral posterior neck pathway in 23-year-old woman with stenosis of left brachiocephalic vein resulting from anterior mediastinal tumor. Early phase left upper extremity venogram shows that most of contrast material runs forward to right brachiocephalic vein through anterior jugular arch (A), then drains into superior vena cava (S); however, left vertebral vein (V, arrowheads) and internal jugular vein (IJ, arrow) are also opacified. Left brachicephalic vein is compressed and occluded by tumor.

 


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Fig. 11B. Contralateral posterior neck pathway in 23-year-old woman with stenosis of left brachiocephalic vein resulting from anterior mediastinal tumor. Delayed phase left upper extremity venogram shows bilateral vertebral veins (arrows) and perivertebral venous plexus (P) more clearly than early phase. RV = right vertebral vein, LV = left vertebral vein, SVC = superior vena cava.

 

Downhill Varices
Esophageal varices in patients with superior vena cava obstruction are called downhill varices because the direction of flow is the reverse of that in the varices of portal hypertension. The varices are usually limited to the upper third of the esophagus, and bleeding from the varices is rare [9].

The submucosal enhancement of the esophagus is seen through the longitudinal prevertebral veins on contrast-enhanced CT (Fig. 12).



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Fig. 12. Downhill varices in 62-year-old man with left upper lobectomy because of lung cancer. Transverse contrast-enhanced CT scan shows that right half (arrows) of esophagus (E) is opacified through longitudinal prevertebral vein, indicating downhill varices.

 

Pseudoparatracheal Node
When the right vertebral vein has not yet been fully enhanced in the early phase of contrast-enhanced CT, the prominent right vertebral vein ending at the lower portion of the right brachiocephalic vein looks like an unenhanced nodule that resembles the right paratracheal lymph node (Fig. 13A,13B,13C,13D). It is necessary to take additional scans of the lower neck and upper thorax in the delayed phase and to observe the continuity of the "nodule" to distinguish the right vertebral vein from the paratracheal lymph node.



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Fig. 13A. Right vertebral vein resembles paratracheal node in 62-year-old man with lung cancer in left upper lobe. Early (A) and delayed (B) phase scans of transverse contrast-enhanced CT show nonenhancing small nodule (arrow, A) at right aspect of trachea, which is similar to paratracheal node. On delayed phase scan, nodule (arrow, B) adjacent to trachea is enhanced same as vessels. Although vertebral vein usually ends at upper portion of brachiocephalic vein, right vertebral vein ends at lower portion of right brachiocephalic vein in this particular patient, which is why right vertebral vein resembles right paratracheal node.

 


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Fig. 13B. Right vertebral vein resembles paratracheal node in 62-year-old man with lung cancer in left upper lobe. Early (A) and delayed (B) phase scans of transverse contrast-enhanced CT show nonenhancing small nodule (arrow, A) at right aspect of trachea, which is similar to paratracheal node. On delayed phase scan, nodule (arrow, B) adjacent to trachea is enhanced same as vessels. Although vertebral vein usually ends at upper portion of brachiocephalic vein, right vertebral vein ends at lower portion of right brachiocephalic vein in this particular patient, which is why right vertebral vein resembles right paratracheal node.

 


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Fig. 13C. Right vertebral vein resembles paratracheal node in 62-year-old man with lung cancer in left upper lobe. Transverse contrast-enhanced delayed phase CT scans shows that right vertebral vein (arrows) is accompanied by vertebral artery (arrowhead, A) on upper axial image (C) and drains into posterior aspect of right brachiocephalic vein (asterisk, D) on lower axial image (D). S = right subclavian artery, star = left brachiocephalic vein.

 


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Fig. 13D. Right vertebral vein resembles paratracheal node in 62-year-old man with lung cancer in left upper lobe. Transverse contrast-enhanced delayed phase CT scans shows that right verterbal vein (arrows) is accompanied by vertebral artery (arrowhead, A) on upper axial image (C) and drains into posterior aspect of right brachiocephalic vein (asterisk, D) on lower axial image (D). S = right subclavian artery, star = left brachiocephalic vein.

 

In summary, the vertebral venous system is a valveless plexiform network with a longitudinal pattern [8]. This venous system enables communication of systemic veins and serves an important role as collateral vessels, especially in patients with venous stenosis or obstruction.


Acknowledgments
 
We thank T. Sato, Department of Anatomy, Tokyo Medical and Dental University, for cooperation in cadaver dissection, and Jan E. Oda-Biro for manuscript preparation.


References
Top
Introduction
Vertebral Veins
Perivertebral Venous Plexuses
Communications Between Vertebral...
Clinical Significance
References
 

  1. Batson OV. The function of the vertebral veins and their role in the spread of metastases. Ann Surg 1940;112:138 -149[Medline]
  2. Anderson R. Diodrast studies of the vertebral and cranial venous systems. J Neurosurg 1951;8:411 -422
  3. Richard HM III, Selby JB Jr, Gay SB, Tegtmeyer CJ. Normal venous anatomy and collateral pathways in upper extremity venous thrombosis. RadioGraphics 1992;12:527 -534[Abstract]
  4. Chasen MH, Charnsangavej C. Venous chest anatomy: clinical implications. In: Greene R, Muhm JR, eds. Syllabus: a categorical course in diagnostic radiology. Oak Brook, IL: Radiological Society of North America, 1992:121 -134
  5. Lewis WH, ed. Gray's anatomy of the human body, 21st ed. Philadelphia: Lea & Febiger, 1924: 653-655
  6. Russell EJ, D'Angelo CM, Zimmerman RD, Czervionke LF, Huckman MS. Cervical disk hernia: CT demonstration after contrast enhancement. Radiology 1984;152:703 -712[Abstract/Free Full Text]
  7. Greitz T, Liliequist B, Müller R. Cervical vertebral phlebography. Acta Radiol 1962;57:353 -365
  8. Batson OV. The vertebral vein system. AJR 1957;78:195 -212
  9. Felson B, Lessure AP. "Downhill" varices of the esophagus. Dis Chest 1964;46:740 -746[Medline]

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