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 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 10  |  Issue : 2  |  Page : 75-78

A cadaveric study of anterior communicating artery


Associate Professor, Department of Anatomy, Government Medical College, (Affiliated to Kerala University of Health Sciences), Kannur, Kerala, India

Date of Submission30-Oct-2020
Date of Decision29-Dec-2020
Date of Acceptance30-Jan-2021
Date of Web Publication09-Apr-2021

Correspondence Address:
G N Geetha
Associate Professor, Department of Anatomy, Government Medical College, Kannur, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/NJCA.NJCA_71_20

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  Abstract 


Background: Anterior communication artery is a collateral channel that connects the right and left anterior cerebral arteries in the circle of Willis. This helps in stabilizing the cerebral blood flow. Different types of variations of this artery were reported in the previous studies. The hemodynamic changes in the blood flow produced by variations induce strain at the sites of bifurcation, which may result in the formation of aneurysms. This commonly occurs at the meeting point of anterior communicating artery (ACoA) with the anterior cerebral artery. The anatomical variations in this portion may complicate the planning and performance of surgery which in turn will lead to postoperative complications. Methodology: The study was conducted in 60 specimens of the brain in the department of anatomy, Government Medical college, Calicut. The artery was carefully dissected and observed. Photographs were taken. The observations were tabulated. Results: Variations were noted in 15 specimens (25%). Duplication of the artery was noted in 6 specimens (10%), hypoplasia in 3 specimens (5%), V-type artery in 1 specimen, and X-type in 6 specimens (10%). There was no triplication or plexiform type noted. An accessory anterior cerebral artery was noted in 3 specimens (5%). Conclusions: As the ACoA acts a collateral channel that stabilizes the cerebral blood flow, when there is any vascular occlusion in any components of the circle, the knowledge of these anatomical variations becomes significant. As the radiological and neurosurgical interventions are increasingly performed, nowadays, the surgeons and radiologists should be aware of these variations in the cerebral arteries.

Keywords: Collateral, duplication, hypoplasia, variation


How to cite this article:
Narayanan S, Geetha G N. A cadaveric study of anterior communicating artery. Natl J Clin Anat 2021;10:75-8

How to cite this URL:
Narayanan S, Geetha G N. A cadaveric study of anterior communicating artery. Natl J Clin Anat [serial online] 2021 [cited 2021 Jun 18];10:75-8. Available from: http://www.njca.info/text.asp?2021/10/2/75/313516




  Introduction Top


An arterial anastomosis is present at the base of the brain, which connects the internal carotid artery with the vertebrobasilar systems, known as the circulus arteriosus (circle of Willis). It has two anterior cerebral arteries from the internal carotid arteries on either side joined by an anterior communicating artery (ACoA) in the anterior part. In the posterior part, there are two posterior cerebral arteries from the basilar artery, which are connected to the internal carotid artery of the respective sides by a posterior communicating artery. These component arteries of the circle vary in the pattern and caliber.[1]

The intracranial saccular aneurysms, which might rupture and produce subarachnoid hemorrhage, are commonly found in the communicating artery in the anterior part of the circle and are frequently associated with an asymmetrical circle of Willis.[2] The fenestration deformity of this artery is easily misdiagnosed as an aneurysm in the computed tomography (CT) angiography of the brain.[3],[4] Therefore, these variations should be kept in mind while evaluating a CT angiogram for aneurysm.[5]

The knowledge of these variations becomes important when this part of the brain is exposed for various surgical procedures and improves the success rate of neurosurgeries.[6] This study aims at studying the ACoA for any variations, which the neurosurgeons and radiologists should be aware of while doing a surgery and also while evaluating a cerebral angiogram.


  Materials and Methods Top


In an observational study, 60 cadaveric brains were obtained from the Department of Anatomy, Government Medical College, Calicut, which were evaluated for the variations in ACoA. The study protocol was approved by the Institutional Ethics Committee. The study was part of thesis work on variations of circle of Willis. Only ACoA details are presented in this article.

The traumatized specimens and those with gross lesions were excluded from the study. They were numbered and fixed in formalin. The component arteries of the circle were dissected. The ACoA was noted for any variations (presence, number, hypoplasia, and orientation). Using a divider and scale, the external diameter of the vessel was taken. Here, an artery was considered as hypoplastic if its external diameter is <1 mm. The photographs were taken.


  Results Top


In the 60 brain specimens studied, the artery was normal in 45 specimens (75%) and the variations were noted in 15 specimens (25%) and double in 6 (10%) specimens [Figure 1]. In one specimen, a “V-shaped” double ACoA was noted [Figure 2], X-type in 6 (10%) specimens [Figure 3], and hypoplastic in 3 (4%) specimens [Figure 4]. Absence, triplication, or plexiform type of artery was not observed in the present study. The orientation of the vessel was in a transverse plane in 34 (56.7%) specimens [Figure 1], in an anteroposterior plane in 14 (23.3%) specimens [Figure 5], and in oblique plane in 12 (20%) specimens [Figure 6].
Figure 1: Circle of Willis showing double anterior communicating artery

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Figure 2: Circle of Willis showing V-type anterior communicating artery

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Figure 3: Circle of Willis showing X-type anterior communicating artery

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Figure 4: Circle of Willis showing hypoplastic anterior communicating artery

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Figure 5: Circle of Willis showing anteroposterior orientation of anterior communicating artery

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Figure 6: Circle of Willis showing oblique orientation of anterior communicating artery

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A third anterior cerebral artery, arising from the ACoA, was found in 3 specimens [Figure 7]. It is also known as accessory anterior cerebral artery (AACA). Its caliber was almost the same as that of the anterior cerebral arteries.
Figure 7: Circle of Willis showing accessory anterior cerebral artery

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  Discussion Top


The duplication of the ACoA was the most common variation observed here, which was found in 10% of cases. Pai et al.[7] had reported duplication of the artery in as high as 20% cases and Puchades et al.[8] in as low as 6.4% of cases. De Ranil and De Silva[9] and Kardile et al.[10] had reported it in 10% of cases in their study which matches with the present study.

Various kinds of duplications were noted by previous workers. However, apart from a “V-shaped” duplication of the artery in 1 case, other kinds of duplication were not observed in this study.

In the previous studies, triplications and plexiform types of the artery were noted by different workers. Karim et al. have reported a double ACoA joined in the middle by a short segmental artery.[11] However, there were no such variations observed in this study [Table 1].
Table 1: Variations of anterior communicating artery as observed by other workers

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An X-type communicating artery, as described in earlier studies, in which there is fusion between the two anterior cerebral arteries at a narrow point, was present in 6 cases.

Windle[12] had reported this type of communication as the absence of ACoA in his work. However, Alpers et al.[13] had reported such a communication in 2% of cases. It was observed here in 10% of cases which was consistent with the observation made by Serizawa et al.[14] [Table 1].

True absence of ACoA was described as a very rare variation by previous workers. Puchades et al.[8] had reported it in 3.2% of their series and Poorwa et al.[10] had reported it in 8% of cases. The artery was hypoplastic in 5% of cases in the present study. Puchades et al.[8] had reported it in 6.4% of cases and Poorwa et al.[10] reported it in 6% of cases. Alpers et al.'s[13] found this in as low as 3% of cases and Riggs and Rupp's[15] reported as high as 27% of cases of hypoplastic arteries [Table 1].

In the present study, the artery was found above the optic chiasma in a transverse plane in 56.7% of the cases, in an oblique plane in 20%, and in an anteroposterior plane in 23.3%. Perlmutter et al.[24] had also reported similar observations without mentioning their incidence. According to them, the anterior part of the circle with the communicating artery is difficult to visualize in angiography as the plane of orientation of the artery differs in different brains. Hence, in addition to the anteroposterior and lateral views, angiography may also be taken in oblique position to outline the artery.

The AACA was found in 5% of cases. De Ranil and De Silva[9] observed it in as low as 2% of cases, Windle[12] in 4.5% of cases, and Ogawa et al.[16] in 13.1% cases.

The ACoA develops as a network of anastomosing small arteries in a 18-mm-size human embryo connecting the two anterior cerebral arteries. Later, this network disappears partly and persists as a single ACoA in adults.[25] If this arterial network persists, it will appear as plexiform type or duplicated type of ACoA, as was observed in the present study. This may produce hemodynamic changes in the blood flow through the arteries which induce strain at the weak points of the arteries resulting in the formation of aneurysms.[26]


  Conclusions Top


Variations were present in 25% of specimens. Among the variations, duplication and X-type artery was noted most frequently (10%). Hypoplasia was noted only in 5% of cases. A V-type artery was noted in a case. An AACA was found in 5% of cases. There was no absence of ACoA. As variations of the circle of Willis may play a role in the development of aneurysms, the surgeons and the radiologists should be aware of these types of variations.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Stranding S. Gray's Anatomy the anatomical basis of clinical practice.39th edition, Elsevier Churchill Livingstone.2005:301.  Back to cited text no. 1
    
2.
Ujiie H, Liepsch DW, Goetz M, Yamaguchi R, Yonetani H, Takakura K. Hemodynamic study of the anterior communicating artery. Stroke 1996;27:2086-93.  Back to cited text no. 2
    
3.
Yasui T, Kishi H, Komiyama M, Iwai Y, Yamanaka K, Nishikawa M, et al. The limitations of three-dimensional CT angiography (3D-CTA) in the diagnosis of cerebral aneurysms. No Shinkei Geka 2000;28:975-81.  Back to cited text no. 3
    
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Okahara M, Kiyosue H, Mori H, Tanoue S, Sainou M, Nagatomi H. Anatomic variations of the cerebral arteries and their embryology: A pictorial review. Eur Radiol 2002;12:2548-61.  Back to cited text no. 4
    
5.
Wiebers DO, Whisnant JP, Huston J 3rd, Meissner I, Brown RD Jr., Piepgras DG, et al. Unruptured intracranial aneurysms: Natural history, clinical outcome, and risks of surgical and endovascular treatment. Lancet 2003;362:103-10.  Back to cited text no. 5
    
6.
Poudel PP, Bhattarai C. Anomalous formation of the circulus arteriosus and its clinico-anatomical significance. Nepal Med Coll J 2010;12:72-5.  Back to cited text no. 6
    
7.
Pai SB, Kulkarni RN, Varma RG. Microsurgical anatomy of the anterior cerebral artery – anterior communicating artery complex: An Indian study. Neurol Asia 2005;10:21-8.  Back to cited text no. 7
    
8.
Puchades-Orts A, Nombela-Gomez M, Ortuño-Pacheco G. Variation in form of circle of Willis: Some anatomical and embryological considerations. Anat Rec 1976;185:119-23.  Back to cited text no. 8
    
9.
De Silva KR, Silva R, Gunasekera WS, Jayesekera RW. Prevalence of typical circle of Willis and the variation in the anterior communicating artery – A study of a Srilankan population. Ann Indian Acad Neurol 2009;12:157-61.  Back to cited text no. 9
    
10.
Kardile PB, Ughade JM, Pandit SV, Ughade MN. Anatomical variations of anterior communicating artery. J Clin Diagn Res 2013;7:2661-4.  Back to cited text no. 10
    
11.
Karim FA, Sharma JD, Taludkar KL. An unusual variation in the anterior communicating artery of the circle of Willis in the human brain – A case report. Nat J Clin Anat 2016;5:39-43.  Back to cited text no. 11
    
12.
Windle BC. The arteries forming the circle of Willis. J Anat Physiol 1888;22:289-93.  Back to cited text no. 12
    
13.
Alpers BJ, Berry RG, Paddison RM. Anatomical studies of the circle of Willis in normal brain. AMA Arch Neurol Psychiatry 1959;81:409-18.  Back to cited text no. 13
    
14.
Serizawa T, Saeki N, Yamaura A. Microsurgical anatomy and clinical significance of the anterior communicating artery and its perforating branches. Neurosurgery 1997;40:1211-6.  Back to cited text no. 14
    
15.
Riggs HE, Rupp C. Variation in form of circle of Willis. The relation of the variations to collateral circulation: Anatomic analysis. Arch Neurol 1963;8:8-14.  Back to cited text no. 15
    
16.
Ogawa A, Suzuki M. Sakurai Y, Yoshimoto T. Vascular anomalies associated with aneurysms of the anterior communicating artery: Microsurgical observations. J Neurosurg 1990;72:706-9.  Back to cited text no. 16
    
17.
Fawcett E, Blachford JV. The circle of Willis: An examination of 700 specimens. J Anat Physiol 1906;40:63-70.  Back to cited text no. 17
    
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Kapoor K, Singh B, Dewan LI. Variations in the configuration of the circle of Willis. Anat Sci Int 2008;83:96-106.  Back to cited text no. 18
    
19.
Stopford JS. The arteries of the Pons and medulla oblongata. J Anat Physiol 1915;50:131-64.  Back to cited text no. 19
    
20.
Niizuma H, Kwak R, Hatanaka M, Suzuki J. Anterior communicating artery aneurysms with associated anomalies. J Neurosurg 1980;52:162-4.  Back to cited text no. 20
    
21.
Eftekhar B, Dadmehr M, Ansari S, Ghodsi M, Nazparvar B, Ketabchi E. Are the distributions of variations of circle of Willis different in different populations?-Results of an anatomical study and review of literature. BMC Neurol 2006;6:22.  Back to cited text no. 21
    
22.
Jayasree N, Sadasivan G. Variations of circle of Willis in man. J Anat Soc India 1981;30:72-7.  Back to cited text no. 22
    
23.
Gasca Gonzalez OO, Delgado-Reyes L, Perez Cruz JC. Microsurgical anatomy of the extracerebral segment of recurrent artery of Huebner in the Mexican population. Cir Cir 2011;79:201-6.  Back to cited text no. 23
    
24.
Perlmutter D, Rhoton AL. Microsurgical anatomy of the anterior cerebral- anterior communicating- recurrent artery complex. J Neurosurg 1976;45:259-72.  Back to cited text no. 24
    
25.
Berk ME. Some anomalies of the circle of Willis. Br J Anat 1961;34:221-6.  Back to cited text no. 25
    
26.
Macchi C, Catini C, Federico C, Gulisano M, Pacini P, Cecchi F, et al. Magnetic resonance angiographic evaluation of circulus arteriosus cerebri (circle of Willis): A morphologic study in 100 human healthy subjects. Ital J Anat Embryol 1996;101:115-23.  Back to cited text no. 26
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
 
 
    Tables

  [Table 1]



 

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