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Anomalous External Carotid Artery-Internal Carotid Artery Anastomosis in Two Patients with Proximal Internal Carotid Arterial Remnants.

Kim CH, Cho YD, Kang HS, Kim JE, Jung SC, Ahn JH, Han MH - Korean J Radiol (2015)

Bottom Line: The ICA remnant of one patient (identifiable immediately upon bifurcation of the common carotid artery) was hypoplastic, and that of the other patient was an occluded arterial stump.These features are not typical of non-bifurcating ICA.The occipital artery originated from an anomalous connection in one instance and from the main trunk of the ECA (just past the ECA-ICA connection) in the other.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Stroke Center, Myongji Hospital, Goyang 412-270, Korea.

ABSTRACT
Two angiographic instances of anomalous external carotid artery (ECA) and internal carotid artery (ICA) anastomosis are described, each occurring at the C2-3 level and bearing remnants of proximal ICA. The ICA remnant of one patient (identifiable immediately upon bifurcation of the common carotid artery) was hypoplastic, and that of the other patient was an occluded arterial stump. These features are not typical of non-bifurcating ICA. The occipital artery originated from an anomalous connection in one instance and from the main trunk of the ECA (just past the ECA-ICA connection) in the other.

No MeSH data available.


Related in: MedlinePlus

Schematic illustration of presented case in comparison with normal ICA-ECA development and non-bifurcating cervical carotid artery.A-C. Illustration for development of normal internal carotid artery and external carotid artery. D, E. Illustrations for typical non-bifurcating cervical carotid artery (D) and presented cases (E). a = artery, AI = first aortic arch, AII = second aortic arch, AIII = third aortic arch, AIV = forth aortic arch, CCA = common carotid artery, ECA = external carotid artery, ICA = internal carotid artery
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Figure 3: Schematic illustration of presented case in comparison with normal ICA-ECA development and non-bifurcating cervical carotid artery.A-C. Illustration for development of normal internal carotid artery and external carotid artery. D, E. Illustrations for typical non-bifurcating cervical carotid artery (D) and presented cases (E). a = artery, AI = first aortic arch, AII = second aortic arch, AIII = third aortic arch, AIV = forth aortic arch, CCA = common carotid artery, ECA = external carotid artery, ICA = internal carotid artery

Mentions: Embryologically, the ICA originated from the third aortic arch and then continues to a successive dorsal aortic arch root; and the ECA arises as a new branch from the ventral aspect of the third aortic arch (Fig. 3A-C) (12). The anomalous ECA-ICA anastomoses described here and the NBCCA seem to be similar developmental variants. There have been two hypotheses to explain the development of the NBCCA: 1) agenesis of the main trunk of the ECA and 2) agenesis of the proximal ICA segment, with persistence of the hyoid-stapedial system that connects ICA with ECA at C1 level (Fig. 3D) (124). However, demonstration of a remnant ICA or carotid stump in these two patients suggests that the NBCCA results from the normal development of the main ECA trunk along with agenesis or hypogenesis of the proximal ICA segment (Fig. 3E). In addition to the identifiable origin of ICA, the level of anomalous ECA-ICA anastomoses observed in this study (C2-3) differed from the typical level (C1), which has been reported on the NBCCA. The exact cause for discrepancy in the level of anastomoses remains elusive. However, the authors conjecture that it may be caused by downward transposition of the hyoid-stapedial system (persistence of the second aortic arch) or a development of alternate vessels other than the hyoid-stapedial system. In the second case, the carotid stump might have been caused by acquired conditions (such as dissected occlusion), in consideration of the fact that the end of the occlusion had a sharp margin.


Anomalous External Carotid Artery-Internal Carotid Artery Anastomosis in Two Patients with Proximal Internal Carotid Arterial Remnants.

Kim CH, Cho YD, Kang HS, Kim JE, Jung SC, Ahn JH, Han MH - Korean J Radiol (2015)

Schematic illustration of presented case in comparison with normal ICA-ECA development and non-bifurcating cervical carotid artery.A-C. Illustration for development of normal internal carotid artery and external carotid artery. D, E. Illustrations for typical non-bifurcating cervical carotid artery (D) and presented cases (E). a = artery, AI = first aortic arch, AII = second aortic arch, AIII = third aortic arch, AIV = forth aortic arch, CCA = common carotid artery, ECA = external carotid artery, ICA = internal carotid artery
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4499558&req=5

Figure 3: Schematic illustration of presented case in comparison with normal ICA-ECA development and non-bifurcating cervical carotid artery.A-C. Illustration for development of normal internal carotid artery and external carotid artery. D, E. Illustrations for typical non-bifurcating cervical carotid artery (D) and presented cases (E). a = artery, AI = first aortic arch, AII = second aortic arch, AIII = third aortic arch, AIV = forth aortic arch, CCA = common carotid artery, ECA = external carotid artery, ICA = internal carotid artery
Mentions: Embryologically, the ICA originated from the third aortic arch and then continues to a successive dorsal aortic arch root; and the ECA arises as a new branch from the ventral aspect of the third aortic arch (Fig. 3A-C) (12). The anomalous ECA-ICA anastomoses described here and the NBCCA seem to be similar developmental variants. There have been two hypotheses to explain the development of the NBCCA: 1) agenesis of the main trunk of the ECA and 2) agenesis of the proximal ICA segment, with persistence of the hyoid-stapedial system that connects ICA with ECA at C1 level (Fig. 3D) (124). However, demonstration of a remnant ICA or carotid stump in these two patients suggests that the NBCCA results from the normal development of the main ECA trunk along with agenesis or hypogenesis of the proximal ICA segment (Fig. 3E). In addition to the identifiable origin of ICA, the level of anomalous ECA-ICA anastomoses observed in this study (C2-3) differed from the typical level (C1), which has been reported on the NBCCA. The exact cause for discrepancy in the level of anastomoses remains elusive. However, the authors conjecture that it may be caused by downward transposition of the hyoid-stapedial system (persistence of the second aortic arch) or a development of alternate vessels other than the hyoid-stapedial system. In the second case, the carotid stump might have been caused by acquired conditions (such as dissected occlusion), in consideration of the fact that the end of the occlusion had a sharp margin.

Bottom Line: The ICA remnant of one patient (identifiable immediately upon bifurcation of the common carotid artery) was hypoplastic, and that of the other patient was an occluded arterial stump.These features are not typical of non-bifurcating ICA.The occipital artery originated from an anomalous connection in one instance and from the main trunk of the ECA (just past the ECA-ICA connection) in the other.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Stroke Center, Myongji Hospital, Goyang 412-270, Korea.

ABSTRACT
Two angiographic instances of anomalous external carotid artery (ECA) and internal carotid artery (ICA) anastomosis are described, each occurring at the C2-3 level and bearing remnants of proximal ICA. The ICA remnant of one patient (identifiable immediately upon bifurcation of the common carotid artery) was hypoplastic, and that of the other patient was an occluded arterial stump. These features are not typical of non-bifurcating ICA. The occipital artery originated from an anomalous connection in one instance and from the main trunk of the ECA (just past the ECA-ICA connection) in the other.

No MeSH data available.


Related in: MedlinePlus