Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 51, Num. 3, 2003, pp. 425

Neurology India, Vol. 51, No. 3, July, 2003, pp. 425

An early and isolated origin of the angular artery from the middle cerebral artery

Kaya AH, Tanriverdi T, Kaynar MY, Erdincler P, Uzel M
Departments of Neurosurgery, Cerrahpasa Medical Faculty in University of Istanbul, Istanbul

Correspondence Address:
Departments of Neurosurgery, Cerrahpasa Medical Faculty in University of Istanbul, Istanbul

Code Number: ni03145

Sir,
Due to its larger diameter and the more distal origin than the other cortical branches, the angular artery has been termed classically as the terminal branch of the middle cerebral artery (MCA),[1] and some anatomical studies have proved the variations of its origin, its division, distribution, and superficial course.[2],[3] The purpose of this short report is to describe an early and isolated origin of an angular artery from the middle cerebral artery, which has not been mentioned in previous studies.

This variation was observed in an anatomical study of the MCA performed with the help of silicone material injection in the arterial system of the brains of ten cadavers. Both the carotid and vertebral arteries were verified first by cervical dissection, and cannulated with appropriate aspiration tubes. Semi-liquid silicone material was then injected through these tubes. Twenty-four hours later, the brains were decapitated and MCA territories were exposed by dissection of the entire Sylvian fissures.

In 17 of the 20 hemispheres, the MCA was bipoidal (bifurcating) in type (85%), but tripoidal (trifurcating) in 3 (15%). In the bipoidal group, 13 (76,5%) of the angular arteries were originating from the inferior trunk, and 4 (23,5%) from the superior trunk of the MCA respectively. In the tripoidal group, the origin of the angular artery was observed as the inferior trunk of the MCA in 2, and the middle trunk of the MCA in 1.

When the origin pattern of the angular artery was evaluated, it was the most distal branch of the MCA in 14 hemispheres [Figure-1]. It was one of the most distal branches with either the posterior temporal or posterior parietal arteries or with both of them in 5 [Figure-2], and was an early and isolated branch in 1 of the hemispheres respectively [Figure-3]. The intrasylvian length of the angular arteries measured from the origin to the superficial part exiting the Sylvian fissure varied between 13 and 87 mm with a mean length of 46 mm whereas the diameter of the artery at the level exiting the sylvian fissure was measured as between 0,9 and 1,2 mm.

Although the term parieto-occipital artery was used as synonymous of the angular artery, the former is mainly a terminal branch of the posterior cerebral artery that supplies the superior parietal lobule frequently, whereas the latter is mainly the branch of the MCA supplying the inferior parietal lobule, and is also our interest in this study.[2],[4],[5] There is only one specific anatomic study that satisfactorily describes the origin and superficial course of the angular artery in the literature.[2] Our findings of different intrasylvian lengths ranging between 13 and 87 mm, and early and isolated origin from the MCA indicate additional proximal variations of the angular artery.

As a conclusion, besides usually being the terminal branch of the middle cerebral artery, proximal variations of the origin of the angular artery are also possible and further studies on the subject are recommended.

REFERENCES

1.	Michotey P, Moskow NP, Salamon G. Anatomy of the cortical branches of the middle cerebral artery. In: Newton TH, Potts DG, editors. Radiology of the Skull and Brain. St. Louis: Mosby; 1974. Vol 2. pp. 1471-8.
2.	Marone ACH. Anatomo-surgical study of the human parieto-occipital artery (Angular Artery). Arch Anat Histol Embryol 1985;68:79-92.
3.	Yasargil MG. Microneurosurgery. Stuttgart: Thieme; 1984. Vol 1. pp. 72-91.
4.	Stephens RB, Stilwell DL. Arteries and veins of the human brain. Springfield: Charles Thomas; 1969.
5.	Zeal AA, Rhoton AL. Microsurgical anatomy of the posterior cerebral artery. J Neurosurg 1978;48:534-59.

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