Received: 28 March 2018
Accepted for publication: 28 April 2020
Slov Vet Res 2021: 58 (1): 5 –11
DOI 10.26873/SVR-957-2020
UDC 611.813:611.1:612.13:636.7
Original Research Article
Introduction
A review of the literature shows that the 
basic morphological publications in the field of 
vascularization of the brain were provided by 
Hofman (1) and Jenke (2), where one may find the 
first information on the construction of the middle 
cerebral artery in the dog. More information about 
the construction of the middle cerebral artery and 
its branches in the dog are found in the publication 
of Hebermehl (3). The author dealt with the 
construction of the artery only and discussed the 
topography of its branches on the surface of the 
TELENCEPHALON VASCULARITY IN DOG (Canis lupus f. familiaris)
Krzysztof Kirkiłło-Stacewicz*, Włodzimierz Nowicki, Jan Wach
UTP University of Science and Technology, Faculty of Animal Breeding and Biology, Department of Physiology, Zoophysiotherapy and Animal 
Feeding, Mazowiecka 28, 85-084 Bydgoszcz, Poland
*Corresponding author, E-mail: krzysztof.stacewicz@o2.pl
Abstract: The studies of the vascularization of the cerebrum in dog were performed on 80 cerebral hemispheres. It was found 
that the middle cerebral artery is the strongest vessel supplying blood to the cerebrum. The artery gets divided into ten perma-
nent branches. Two olfactory arteries supply the region of the cerebrum located on the border between the old and the new 
cortex. The other eight supply the region of the new cortex: three branches aiming at the frontal lobe, two branches at the pari-
etal lobe and three temporal branches aiming at temporal area. The frontal, parietal and temporal branches descended inde-
pendently from the main trunk of the middle cerebral artery or formed a common trunk. Common trunks for respective groups 
of branches have been described as the rostral, dorsal and caudal middle cerebral artery. In 2.5% of cases there were two inde-
pendent branches of the middle cerebral artery extending from the rostral cerebral artery.
Key words: brain arteries; dog; vascularity; variability
telencephalon, ignoring its variability. The literature 
concerning the blood supply to the brain describes 
the dog (4,5). These authors mention that the middle 
cerebral artery is one of the vessels departing from 
the arterial circle of the brain. In other predatory 
species similar studies were carried out in the cat 
(6), in the raccoon dog (7). In the literature, there 
are publications outlining in detail the cortical 
branches of the middle cerebral artery. This problem 
was described by Chadzypanagiotis in cat (8), the 
author gives nomenclature for individual cortical 
branches of the artery. Structured descriptions 
of the construction and the course of the cortical 
branches of the middle cerebral artery in some 
predatory species were presented by Wiland (9). 
In recent years there have been numerous studies 
K. Kirkiłło-Stacewicz, W. Nowicki, J. Wach6
that discuss the construction of the middle cerebral 
artery in various mammalian species. This applies 
to vessels which isolate as a single branch, for 
example, in red squirrel (10), in ground squirrel 
(11), in otter (12) and multiple arteries presented 
in domestic pig (13). These publications stated 
that cortical branches of the middle cerebral 
artery in examined species attained the same 
areas of the telencephalon. The differences occur 
in the pattern of descent and division of respective 
cortical branches of the middle cerebral artery. The 
pattern of division of the middle cerebral artery 
is affected by how the species has been classified 
and the pattern of groove-coverage of the cortex. 
In mammals on the surface of the cortex there is 
a different pattern of sulci, which can affect the 
structure of the cortical branches of the middle 
cerebral artery (14). In vast literature there seem 
to be missing a paper on the cortical branches of 
the middle cerebral artery in dog. Considering the 
discrepancy resulting from respective descriptions 
and considering new studies, one has decided to 
investigate the pattern, the division and variation 
of cortical branches of the middle cerebral artery 
in dog and to compare the results with the data 
reported by other authors.
Materials and methods
The research was performed on 40 brains in dog, 
namely a total of 80 cerebral hemispheres received 
from animal shelters in Bydgoszcz. Ethics approval 
was not required since animals died because of 
natural reasons. The animal heads were cut off 
at the height of the 3rd – 4th cervical vertebrae. 
The arteries were filled with latex introduced with 
medical syringe into the common carotid artery. This 
method was described by Godynicki (15). The heads 
were fixed in a 5% formalin solution for 3 months, 
and then decalcified in hydrochloric acid, the skull 
cavity was opened and brains were taken out. The 
cerebral hemispheres were photographed and the 
following were being described: the anatomy, the 
division pattern and the course of cortical branches 
of the middle cerebral artery.
Results
In dog the blood is supplied to the brain with 
internal carotid arteries (Fig. 1-a) and vertebral 
arteries.
Figure 1: Diagram of the division of the middle cerebral artery on the surface of the cortex in dog
1 – rostral olfactory artery, 2 – caudal olfactory artery, 3 – orbital branch, 4 – inferior frontal branch, 5 – dorsal 
frontal branch, 6 – rostral parietal branch, 7 – caudal parietal branch, 8 – dorsal temporal branch, 9 – middle 
temporal branch, 10 – ventral temporal branch, a – internal carotid artery, b – rostral cerebral artery, c- caudal 
communicating artery, d – Sylvian fissure, e – Presylvian sulcus, f – rostral lateral olfactory sulcus, g – caudal 
lateral olfactory sulcus, h – rostral Suprasylvian sulcus, i – middle Suprasylvian sulcus, j – caudal Suprasylvian 
sulcus, k – caudal external Sylvian sulcus, l – middle external Sylvian sulcus, m – coronary sulcus, n – marginal 
sulcus, o – external marginal sulcus.
Telencephalon vascularity in dog (Canis lupus f. familiaris) 7
The internal carotid artery, having entered 
the skull cavity and penetrated the dura mater, 
bifurcates into the rostral cerebral artery (Fig. 1-b) 
and caudal communicating artery (Fig. 1-c) which, 
together with their symmetrical vessels form an 
arterial circle of the brain.
From the initial section of the rostral cerebral 
artery towards the cortex there separates the middle 
cerebral artery.
The middle cerebral artery is the strongest vessel 
supplying blood to the cerebrum. The initial section 
of the main trunk of the middle cerebral artery goes 
along the dorsal surface of the optic tract. Then the 
section gets bended around the piriform lobe and 
goes through its rostral margin. Further on it runs 
to the lateral olfactory sulcus and, having passed it, 
it gets divided. From the initial section of the main 
trunk of the middle cerebral artery there descend 
minor central branches supplying blood to olfactory 
tracts and the piriform lobe. The main trunk of the 
middle cerebral artery gets divided into a number of 
cortical branches which run to the specific region of 
the cerebral hemisphere, supplying blood to specific 
regions of the brain. 
The first permanent branches of the middle 
cerebral artery which supply both the old and the 
new cortex are olfactory arteries.
The rostral olfactory artery (Fig. 1-1), having 
separated from the main trunk of the middle cerebral 
artery it creates an arch and runs to the rostral 
part of the lateral olfactory sulcus it can ascend 
into in various places. Its terminal branches can 
also appear again from under the lateral olfactory 
sulcus and then ascend under the cortex surface. 
The caudal olfactory artery (Fig. 1-2) ascends 
into the caudal part of the lateral olfactory sulcus 
and its terminal branches supply the area of the 
cortex found under the sulcus. 
The other branches of the middle cerebral artery 
supply the areas of the cortex over the lateral 
olfactory sulcus. On the cortex towards the frontal 
lobe there spread three thick branches. As the first 
one there separates the orbital branch (Fig. 1-3) 
which is located lowest and it goes towards the 
region of the Presylvian sulcus where its terminal 
branches reach the coronary sulcus.
The ventral frontal branch (Fig. 1-4) vascularizes 
the middle part of the frontal lobe. The vessel goes 
through the rostral external Sylvian sulcus and the 
rostral Suprasylvian sulcus towards the coronary 
sulcus it passes towards the fornix.
The dorsal frontal branch (Fig. 1-5), having 
separated from the middle cerebral artery at the 
height of the rostral external Sylvian sulcus, goes 
up to the region of the cruciate sulcus. The vessel 
supplies blood to the upper part of the medial 
surface of the frontal lobe.
The next vessel which runs towards the parietal 
lobe bifurcates into two branches. 
The rostral parietal branch (Fig. 1-6) runs 
towards the middle external Sylvian sulcus to the 
marginal sulcus. The terminal twigs of that vessel 
supply blood to the area of the cortex found under 
the ansiform sulcus.
The caudal parietal branch (Fig. 1-7) also runs 
to the region of the marginal sulcus and further on 
it branches out into smaller vessels. Some of them 
ascend into the medial Suprasylvian sulcus.
The lateral-caudal surface of the cerebral 
hemisphere is supplied by the branches of the 
middle cerebral artery which descend from at 
various heights and they are referred to as  temporal 
branches. 
The dorsal temporal branch (Fig. 1-8) having 
left the Sylvian fissure, it runs towards the middle 
Suprasylvian sulcus and further to the upper 
margin of the cerebral hemisphere. It is uasually 
the strongest cortical branch of the middle cerebral 
artery. The branch supplies blood to the upper part 
of the cortex.
The middle temporal branch (Fig. 1-9) descends 
a small distance away from the previous branch. 
The branches of that vessel spread towards the 
external marginal sulcus. Its terminal branches go 
onto the surface of the occipital lobe.
The ventral temporal branch (Fig. 1-10) runs 
to the end of the caudal external Sylvian sulcus. 
Having passed the caudal part of the sulcus, its 
branches spread towards the caudal Suprasylvian 
sulcus. Its terminal branches take part in the 
supply of a part of the occipital lobe. 
Considering the general pattern of the spread 
the cortical branches of the middle cerebral artery 
in dog, one shall note that respective sections of 
those branches can run inside respective sulci and 
divide, always running towards the cortex areas 
described. 
Analysing the pattern of descent of the cortical 
branches of the middle cerebral artery in the dog, it 
was found that from the rostral cerebral artery on 
78 (97,5%) cerebral hemispheres there descended 
a single independent vessel - the middle cerebral 
artery. Among them on 8 (10%) hemispheres from 
the main trunk there descended rostrally with a 
K. Kirkiłło-Stacewicz, W. Nowicki, J. Wach8
common trunk: the orbital branch, the ventral 
frontal branch and the rostral olfactory artery. 
The main trunk of the middle cerebral artery, got 
onto the surface of the cerebral cortex and formed 
a common descent for the dorsal frontal branch 
as well as rostral and caudal parietal branches. 
Caudally from the main trunk of the middle cerebral 
artery, with a common trunk there separated the 
dorsal, middle and ventral temporal branches and 
the independent caudal olfactory artery. (Fig. 1). 
In another 12 (15%) cases there descended 
rostrally an independent rostral olfactory artery 
and a common trunk for the orbital, rostral and 
dorsal frontal branches. The main trunk got onto 
the surface of the cerebral cortex from the Sylvian 
fissure and formed a common descent for rostral 
and caudal parietal branches. Caudally from the 
main trunk of the middle cerebral artery, with a 
common trunk there separated the dorsal, middle 
and ventral temporal branches, whereas the caudal 
olfactory artery got separated independently from 
the main trunk of the middle cerebral artery. 
On another 12 (15%) hemispheres from the 
main trunk of the middle cerebral artery there 
separated rostrally a common trunk for the rostral 
olfactory artery and for the orbital branch as well 
as the common descent for the ventral and dorsal 
frontal branch. The main trunk separated caudally 
the caudal olfactory artery with a common descent 
with the ventral temporal branch. The main trunk, 
having ascended into the Sylvian fissure, on the 
surface of the cortex it showed a common trunk for 
rostral and caudal parietal branches as well as for 
the middle and dorsal temporal branches.
On another 14 (17,5%) cerebral hemispheres 
from the main trunk of the middle cerebral artery 
departed the independent rostral olfactory artery 
and a common departure for the ventral and dorsal 
frontal branches. Caudally from the main trunk 
there descended the middle and ventral temporal 
branch through the common trunk with the caudal 
olfactory artery. The main trunk, having descended 
into the Sylvian fissure, got onto the surface of 
the cortex with a common descent for rostral and 
caudal parietal branches as well as the rostral and 
dorsal temporal branch.
On another 12 (15%) hemispheres from the 
main trunk the following separated rostrally with 
a common trunk: the rostral olfactory artery, 
common trunk for the orbital branch, the ventral 
frontal branch. The caudal branch was a common 
descent for the ventral temporal branch and the 
caudal olfactory artery. The main trunk, having 
descended into the Sylvian fissure, got onto the 
surface of the cortex with a common descent for the 
dorsal frontal branch, rostral and caudal parietal 
branches as well as the middle and dorsal temporal 
branch.
On yet another 6 (7,5%) cerebral hemispheres 
from the main trunk rostrally there separated, 
with a common descent, the orbital branch, the 
ventral and dorsal frontal branch and the rostral 
olfactory artery. Caudally from the main trunk of 
the middle cerebral artery the following separated 
with a common descent: rostral and caudal parietal 
branches as well as the ventral, middle and dorsal 
temporal branches. The caudal olfactory artery 
departed independently from the main trunk.
On another 14 (17,5%) cerebral hemispheres 
from the main trunk of the middle cerebral artery 
the following departed rostrally with the common 
trunk:  the orbital branch, the ventral frontal 
branch and the rostral olfactory artery. Caudally 
from the main trunk of the middle cerebral artery 
there descended with the common descent: the 
dorsal frontal branch, the rostral and caudal 
parietal branches and the dorsal, middle and 
ventral temporal branches. The caudal olfactory 
artery departed independently from the main trunk.
On the other 6 (7,5%) hemispheres it was found 
that from the main trunk of the middle cerebral 
artery there departed the common trunk for the 
rostral olfactory artery and the orbital branch, 
then the common descent for the ventral and 
dorsal frontal branch. The main trunk got onto 
the surface of the cortex with a common descent 
for rostral and caudal parietal branches as well as 
the dorsal, middle and ventral temporal branch. 
The caudal olfactory artery departed caudally from 
the main trunk of the middle cerebral artery as an 
independent vessel.
On the other 2 (2,5%) hemispheres it was found 
that from the rostral cerebral artery in dog there 
bifurcated two independent branches of the middle 
cerebral artery. Among them the first independent 
branch from the rostral cerebral artery was the 
rostral olfactory artery, while the second branch was 
the main trunk of the middle cerebral artery from 
which there descended rostrally independently: 
the orbital branch, the ventral and dorsal frontal 
branch. Caudally from the main trunk there 
separated an independent caudal olfactory artery 
and the ventral temporal branch. The main trunk, 
having descended into the Sylvian fissure, got onto 
Telencephalon vascularity in dog (Canis lupus f. familiaris) 9
the surface of the cortex with a common descent 
for rostral and caudal parietal branches as well as 
the common trunk for dorsal and middle temporal 
branch (Fig.2).
On the other 2 (2,5%) hemispheres it was 
found that from the rostral cerebral artery in dog 
there bifurcated two independent branches of 
the middle cerebral artery. Among them the first 
independent branch from the rostral cerebral 
artery was the rostral olfactory artery, while the 
second branch was the main trunk of the middle 
cerebral artery from which there descended 
rostrally independently: the orbital branch, the 
ventral and dorsal frontal branch. Caudally from 
the main trunk there separated an independent 
caudal olfactory artery and the ventral temporal 
branch. The main trunk, having descended into 
the Sylvian fissure, got onto the surface of the 
cortex with a common descent for rostral and 
caudal parietal branches as well as the common 
trunk for dorsal and middle temporal branch 
(Fig.2).
Discussion
The middle cerebral artery supplies blood to the 
greatest region of the cerebrum and is the most 
shaped branch extending from the rostral cerebral 
1 - rostral olfactory artery, 2 - caudal olfactory artery, 3 - orbital branch, 4 - ventral frontal branch, 5 - dorsal fron-
tal branch, 6 - rostral parietal branch, 7 -  caudal parietal branch, 8 - dorsal temporal branch, 9- middle temporal 
branch, 10 - ventral temporal branch.
Figure 2: Independent departure of the anterior olfactory artery and the main trunk of the middle cerebral artery 
from the rostral cerebral artery
artery. In dog the middle cerebral artery supplies 
the same areas of the brain as in the mammalian 
species studied so far. The discrepancies concern 
mostly its division into respective branches. 
Chadzypanagiotis (8), describing the cortical 
branches in cat, differentiated between the 
branches supplying the old cortex, the branches 
on the border of the old and the new cortex as 
well as the branches for the new cortex. In dog 
the arteries supplying the old cortex are minor 
branches onto the piriform lobe and olfactory 
tracts. On the border of the old and the new cortex 
there are found the rostral and caudal olfactory 
arteries. In dog the rostral olfactory artery in 
2.5% of the cases was a vessel which descended 
independently from the rostral cerebral artery. 
On the other cerebral hemispheres it was a vessel 
which got separated independently from the main 
trunk of the middle cerebral artery in 32.5% of the 
cases. In 22.5% of the cases it formed a common 
departure with the orbital branch. On the 35% 
of the cerebral hemispheres it was one of the 
branches descending from the common trunk of 
the middle cerebral artery which gave rise to the 
orbital branch and the ventral frontal branch. In 
the other 7.5% cases the rostral olfactory artery 
demonstrated a common descent with the orbital, 
ventral and dorsal frontal branches.
K. Kirkiłło-Stacewicz, W. Nowicki, J. Wach10
The caudal olfactory artery, on the other hand, 
in 45% of the cases was a vessel which descended 
independently from the rostral cerebral artery. 
On 37.5% the caudal olfactory artery separated 
with a common descent with the ventral temporal 
branch. In the other 17.5% hemispheres the 
caudal olfactory artery was one of the branches 
of a common trunk for ventral temporal branch. 
In another 20% of the cases it was one of the 
branches of the common trunk for the ventral and 
middle temporal branches. 
The other cortical branches of the middle 
cerebral artery can be divided into a group of 
frontal, parietal and temporal branches. In dog, 
similarly as in other Carnivora species there occur 
eight main vessels which supply blood to the area 
of the new cortex of the cerebrum.
Besides, respective cortical branches can de-
scend from the main trunk of the middle cerebral 
artery with a common descent. Such cases of de-
scent were reported by Wiland (9), Skoczylas et 
al. (12) as the rostral, dorsal and caudal middle 
cerebral artery. In dog the rostral middle cerebral 
artery has been presented as a common trunk for 
frontal branches and it occurred in 32.5% of the 
cases investigated, the dorsal middle cerebral ar-
tery was described as a common trunk for pari-
etal branches, which was observed in 17.5% of 
the cases. The caudal middle cerebral artery as a 
common trunk for temporal branches was found 
in 25% of the cases.
In dog the dorsal middle cerebral artery occurred 
as the lowest percentage of the cases, however, 
here the rostral middle cerebral artery dominated. 
Making a comparison of the present results with 
those reported by Wiland (9) in American mink, 
and by Skoczylas et al. (12) in otter one can state 
the dorsal middle cerebral artery was reported 
as the lowest percentage of the cases. In dog, 
similarly as in the other animal species studied, 
the parietal branches have developed poorest. On 
the surface of the cerebrum the best developed are 
the frontal branches of the middle cerebral artery.
From the description of the structure of the 
middle cerebral artery in the publications by 
Aydin et al. (11), Ozudogru et al. (16), Skoczylas 
et al. (12) in the ground squirrel, common fox and 
otter one can see that it is usually a single vessel 
descending from the rostral cerebral artery. The 
vessel, having passed the lateral olfactory sulcus, 
gets divided along its course into respective cortical 
branches. In the material investigated such a 
pattern of division of the middle cerebral artery 
was found in 97.5% of the cases. In dog there were 
identified the cases of descent from the rostral 
cerebral artery of two independent arterial trunks 
in 2.5% of the cases. The second independent 
branch from the rostral cerebral artery was the 
rostral olfactory artery. In other mammalian 
species the presence of two independent descents 
of the branches of the middle cerebral artery was 
found in rabbit in 31.4% (17), in wild rabbit (18) 
in 36.5% of the cases, in raccoon dog (7) in 18.6% 
of the cases.
The present research show that observed in 
dog the division of the middle cerebral artery 
into the same branches or their groups, like in 
the other mammalian species investigated so far 
is, according to Wiland (19), a result of genetic 
limitations. 
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OŽILJENOST TELENCEFALONA PRI PSIH (Canis lupus f. familiaris)
K. Kirkiłło-Stacewicz, W. Nowicki, J. Wach
Izvleček:  : Študije ožiljenosti možganov pri pseh so bile izvedene na 80 možganskih poloblah. Ugotovljeno je bilo, da je sred-
nja možganska arterija najmočnejša žila, ki dovaja kri v možgane. Arterija se razdeli na deset stalnih vej. Dve vohalni arteriji 
napajata predel možganov, ki se nahaja na meji med staro in novo možgansko skorjo. Ostalih osem arterij oskrbuje področje 
nove skorje: tri veje, ki potekajo do prednjega režnja, dve veji, ki potekata v parietalni reženj in tri temporalne veje, usmerjene 
v temporalno področje. Čelne, parietalne in temporalne veje so se razvejale neodvisno od glavnega debla srednje možgan-
ske arterije, ali pa so tvorile skupno deblo. Običajna debla za posamezne skupine vej so opisana kot rostralna, dorzalna in 
kavdalna srednja možganska arterija. V 2,5 odstotkih primerov sta obstajali dve neodvisni veji srednje možganske arterije, ki 
izhajata iz rostralne možganske arterije.
Ključne besede: možganske arterije; pes; ožiljenost; raznolikost