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Aortic Arch Origin of the Left External Carotid Artery
======================================================

* Sinan Cakirer
* Ercan Karaarslan

We read with interest the article by Horowitz et al (1) in the March 2003 issue of the *AJNR*. The authors described an aortic arch origin of the left external carotid artery associated with a type II preatlantal fetal anastomosis. They claim that their case is unique, because it shows a left external carotid artery originating from the aortic arch.

We would like to draw the authors’ attention to the previously published reports of left external carotid arteries that have separate origins from the aortic arch. A search of the literature starting from 1968 revealed five cases of agenesis of left common carotid artery with separate origins of the left internal and external carotid arteries from the aortic arch. The condition was diagnosed by MR angiography of supraaortic vessels in a case by Cakirer et al (2), by using a combination of intraarterial angiography and duplex sonography in a case by Woodruff et al (3), and by using intraarterial angiography in three other cases by Bryan et al (4), Dahn et al (5), Rossitti et al (6).

The authors also claim that their case is unique in its association with a type II proatlantal intersegmental artery. Lie (7) reported that there were many congenital anomalies associated with separate origins of left internal and external carotid arteries from the aortic arch, including a cervical aortic arch, a double aortic arch, persistent trigeminal artery, and persistent proatlantal segmental artery in an angiographic study and review of congenital anomalies of the carotid arteries.

## References

1.  Horowitz M, Bansal S, Dastur K. **Aortic arch origin of the left external carotid artery and type II proatlantal fetal anastomosis.** AJNR Am J Neuroradiol 2003;24:323–325
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiIyNC8zLzMyMyI7czo0OiJhdG9tIjtzOjIyOiIvYWpuci8yNC83LzE0OTIuMy5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

2.  Cakirer S, Karaarslan E, Kayabali M, Rozanes I. **Separate origins of the left internal and external carotid arteries from the aortic arch: MRA findings.** AJNR Am J Neuroradiol 2002;23:1600–1602
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo5OiIyMy85LzE2MDAiO3M6NDoiYXRvbSI7czoyMjoiL2FqbnIvMjQvNy8xNDkyLjMuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

3.  Woodruff WW III, Strunsky VP, Brown NJ. **Separate origins of the left internal and external carotid arteries directly from the aortic arch: duplex sonographic findings.** J Ultrasound Med 1995;14:867–869
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=8551555&link_type=MED&atom=%2Fajnr%2F24%2F7%2F1492.3.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=A1995TB38400013&link_type=ISI) 

4.  Bryan RN, Drewyer RG, Gee W. **Separate origins of the left internal and external carotid arteries from the aorta.** AJR Am J Roentgenol 1978;130:362–365
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.2214/ajr.130.2.362&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=414596&link_type=MED&atom=%2Fajnr%2F24%2F7%2F1492.3.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=A1978EK48100029&link_type=ISI) 

5.  Dahn MS, Kaurich JD, Brown FR. **Independent origins of the internal and external carotid arteries: a case report.** Angiology 1999;50:755–760
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=10496502&link_type=MED&atom=%2Fajnr%2F24%2F7%2F1492.3.atom) 

6.  Rossitti S, Raininko R. **Absence of the common carotid artery in a patient with a persistent trigeminal artery variant.** Clin Radiol 2001;56:79–81
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1053/crad.1999.0276&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=11162705&link_type=MED&atom=%2Fajnr%2F24%2F7%2F1492.3.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000166454900017&link_type=ISI) 

7.  Lie TA. Congenital anomalies of the carotid arteries: an angiographic study and a review of the literature. Amsterdam: Excerpta Medica Foundation;1968;30–35
    
    

#  {#article-title-2}

*Reply:* 

We greatly appreciate the information provided by Drs. Cakirer and Karaarslan regarding prior reports on aortic arch origins of the external carotid artery along with their association with proatlantal vessels. We apologize for incomplete review of the past literature. Once again, we have had it reinforced in our minds that there is rarely “something new under the sun.” In retrospect, perhaps I should mind the valuable advice given to me by my mentor, Dr. Philip Purdy, several years ago, when he urged me never to say something is being reported for the first time, because one can be sure that this is not true.

*   Copyright © American Society of Neuroradiology