A study on the branching pattern of middle cerebral artery

Sundari, S (2006) A study on the branching pattern of middle cerebral artery. Masters thesis, Madurai Medical College, Madurai.


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INTRODUCTION: It is brought to the light of medical world that the lesion of the middle cerebral artery is the commonest catastrophes among the lesions of arteries of the brain, both internal carotid and vertebro basilar system. In day to day life, due to urbanization of the even rural places, the change in the diet habits, the stress and strain which the people undergo, the tensions and emotions to which the people are subjected to compete with the modernization of the computer world, the sequence of occurrence of middle cerebral artery lesion is still more increased. Usually the lesions are acute in onset, the patient should not have experienced even the earlier symptoms of any pathology in cerebral arteries. Due to poor knowledge of regular clinical checkup among the illiterate people, it is more commonly the illiterate who are subjected to this lesions when compared to the metropolitans. The cerebro vascular catastrophe has become so common that in everyday clinical life we come across so many cases with varying manifestations and varying presentations of cerebral arterial lesions. The lesion may be an isolated lesion, involving either the initial segment of artery or the divisions of artery or the branches of the divisions of the artery or it may be associated with lesions of other cerebral arteries. Depending upon the clinical manifestations and based on the investigations we may have to modify the treatment. It may be either a Haemorrhage or Atheroma or a Thrombus or an Embolus which require different methods in therapy. The therapy varies depending upon the functional areas involved and the duration between the onset of the symptoms and the time the patient get admitted in the hospital and upon the percentage of the ischaemia developed in the functional areas. As per update upto Nov. 18, 2003 the presentation of middle cerebral artery stroke syndrome include the following varied presentation. MATERIALS AND METHODS: Specimens are collected from the post mortem bodies in the Department of Forensic Medicine, Madurai Medical College during the period of this study from October 2004 to September 2006. The cadavers utilised for this study were unclaimed dead bodies received from the Government Rajaji hospital, Madurai. The cadavers were kept in the mortuary cooler for 10days. After fulfillment of the routine administrative formalities, they were received by the Institute of Anatomy, Madurai Medical College, Madurai. The dead bodies were embalmed with the following preservative fluids. Formalin (37-40%) – 500ml, Glycerin - 2 litre, Common salt - 1 kgm, Thymol - Few crystals, Water - q.s. 6 lts. The embalmed cadavers were stored in tanks filled with dilute (10%) formalin. METHOD OF STUDY The branching pattern of middle cerebral artery was studied in 50 brains as follows. M1 SEGMENT: 1) Length of M1 segment. 2) Size of M1 segment. 3) Branches, number Gyrus supplied by it, any other artery to the same gyrus. If so size of lumen of both. 4) Angle of origin. 5) Termination of M1 segment. 6) Lumen size comparison between origin and termination of M1 segment. a) Artery supply to the Broca’s area. b) Artery supply to the frontal eye field. c) Artery to motor and sensory area. d) Artery supply to the sensory cortex, Wernick’s area and auditary cortex. e) Central branches or the lenticulo striate branches. CONCLUSION: It has been observed in all specimens the middle cerebral artery was the largest of the terminal branches of the internal carotid artery arising that lateral the anterior perforated substance. An accessory middle cerebral artery has been reported by Jain 1964, such artery has not been found in the present study. In the present study the size of the lumen of anterior cerebral artery is between 3 to 6mm. The largest diameter of 6mm has been observed in four specimens of which is two specimens the lumen of the Anterior cerebral artery was only 2mm. So it may be concluded that these two cases are more prone for anterior cerebral artery area ischaemia. Length of the artery which is between 14 to 16mm in majority of the specimens agree with the previous works. In this work, the length of Middle cerebral artery in two specimens were only 10mm. In these cases the force of flow will be more and so prone for damage to the tunics of the arteries. In one specimen it was 21mm and in another 30mm and so there is a possibility for sluggish flow which is a predisposing factor for the formation of thrombus. It is observed that there is a uniform reduction in the caliber of the middle cerebral artery from origin to its termination. But in two specimens the lumen and the termination is same as in its origin, which ensues that there is liberal supply to the functional areas only in these two specimens which reduce the risk of cerebrovascular catastrophes. It has been reported in the present study that the Rolandic branch supplies only motor cortex and anterior parietal supplying the sensory cortex in addition to its supply to the parietal association cortex. So It may be concluded that the occlusion of Rolandic giving rise to only motor loss and the occlusion of anterior parietal branch giving rise to hemiparesis and astereognsis. This serves an example of varying clinical manifestation in occlusion of either the division of the branches of the division. It has been observed that the motor speech area supplied by orbitofrontal branch from M1 segment. Frontopolar and Prerolandic branches from superior division. So it may be concluded that this case if there is occlusion to M1 Segments there is motor aphasia. But when the occlusion is in the superior division, this case may escape from Motor Aphasia, since there is a supplying from M1. In the same if the occlusion is prerolandic which usually supplies motor speech area, again it escapes ischaemia. There had been only two lenticulostriate branches and so the Basal Ganglia and the related structures may suffer from deficient blood supply. Since the lumen of Prerolandic and Rolandic branches are equal to the lumen of middle cerebral artery there could be more blood supply to frontal eye field area and the motor and sensory cortex. Since there is a free communication between the angular artery a branch of inferior division and anterior parietal branch, a branch of superior division which supplies the sensory association cortex, in occlusion of superior division astereognosis may not be present. Since the inferior division gives rise to varying degrees of its branches, this variation may be a predisposing factor either for hemorrhage or thrombus formation. It has been observed that there are six branches from inferior division to the auditary receptive cortex and so it one branch it blocked it may be compensated by the other branches. In general it has been observed that there is a few difference with branching pattern of the middle cerebral artery the pattern of one specimen does not correspond to pattern in the other brain. There is a free communications between the branches of the division especially on the left side and the branches of the left side appear to be larger. There is in general less branches and smaller branches on the right side without free communications. On the right side it has been noted that the lenticulostriate branches were less.

Item Type: Thesis (Masters)
Uncontrolled Keywords: branching pattern, middle cerebral artery.
Subjects: MEDICAL > Anatomy
Depositing User: Subramani R
Date Deposited: 05 Oct 2019 07:00
Last Modified: 05 Oct 2019 14:25
URI: http://repository-tnmgrmu.ac.in/id/eprint/11683

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