morphometric anatomy of superficial cerebral veins

Showa Univ. J. Med. Sci. 8(1), 103•`411, June 1996

Original

Morphometric Anatomy of Superficial Cerebral Veins

and Cerebral Sulci

Teru KAWAMATA1), Kiyoshi MATSUMOTO1), Noboru GoTo2)

and Minoru KOHDA3'

Abstract: The morphometric anatomy of the superficial cerebral veins in relation to cerebral gyri was studied in 244 cadaveric cerebral hemispheres. Our morphometry revealed that the position of the central sulcus and that of the

parieto-occipital sulcus near the superior sagittal sinus were at 55% and 83.6% respectively of the half-perimeter running from the frontal pole to the occipital

pole (FO). The drainage position of the central sulcal vein (of Rolando) into the superior sagittal sinus was about 65% of the FO half-perimeter on each side. The three main drainage veins among the superficial cerebral veins are classified into four types: (1) left predominant, (2) right predominant, (3) no laterality, and (4) absent. No laterality predominance was observed regarding the superficial middle cerebral vein (of Sylvius). The inferior anastomotic vein (of Labbe), however, was predominant on the left hemisphere. The superior anastomotic vein (of Trolard) was observed with similar frequency in each type. In conclusion, the superficial cerebral veins can be classified into eight different types according to venous drainages.

Key words: superficial cerebral vein, anastomotic vein, bridging vein, veno-

gram, anatomy

Introduction

Most reports on superficial cerebral veins have been based on angiographic studied1-3).

However, the relationship between superficial cerebral veins and cerebral sulci remains un-

known. It is well known that superficial cerebral veins may frequently vary in size, position,

and connections. It is, therefore, essential to conduct a precise study of the variations of

the superficial cerebral veins in a large number of cadaveric brains. We conducted a study

on 122 Japanese adult cadaveric brains, investigate variations in superficial cerebral veins

in relation to cerebral sulci.

Materials and Methods

Our study of the superficial cerebral veins in relation to cerebral sulci was performed using 266 cerebral hemispheres from 133 Japanese adult cadavers. Formalin was injected through the femoral artery for fixation. After removal of the brain, we observed and measured the location of the superficial cerebral veins in relation to cerebral sulci and gyri.

1) Department of Neurosurgery, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142, Japan. 2) Department of Anatomy

, Showa University School of Medicine. 3) Department of Anatomy , Jikei Medical College.

104 Teru KAWAMATA, et al.

Fig. 1. Schematic diagram showing the perimeter from the frontal pole to the occipital pole (FO), to the central sulcus (FC), and to the parieto-occipital sulcus (FP).

Of the 133 brains, 11 (22 cerebral hemispheres) showed evidence of central nervous disease or damage to the superficial cerebral veins which might have occurred during removal of

the brain and were, therefore, discarded. The remaining 122 brains (244 cerebral hemi-spheres) were obtained from 65 men and 57 women, ranging in age from 41 to 96 years

(average, 73.6 years).Locations were determined from the frontal pole of the central and parieto-occipital sulci

on the perimeter measured near the longitudinal fissure. We measured the half-perimeter from the frontal pole to the occipital pole (FO), from the frontal pole to the central sulcus near the midline (FC), and from the frontal pole to the parieto-occipital sulcus at the ex-ternal end (FP), and the average distance on a straight line from the frontal pole to the occipital pole (FOD) and from the frontal pole to the projection of the preoccipital notch

(preoccipital incisura) on the FO line (FPOD) (Fig. 1).The three main drainage veins among the superficial cerebral veins are the superficial

middle cerebral vein (SMCV), the superior anastomotic vein (SAV), and the inferior ana-stomotic vein (IAV). We also measured the venous diameters where they drained into the dural sinuses, and counted the number of SMCVs, SAVs, IAVs, and other superficial cerebral veins on each side. Superficial cerebral veins were classified for convenience into three groups according to venous diameters: small (less than 1 mm in diameter), medium

(1 to 3 mm in diameter), and large (more than 3 mm in diameter). We observed the later-ality of their blood flow according to the size group of total venous diameters. Laterality was classified as: (1) left predominant, (2) right predominant, (3) no laterality, or (4) absent. We examined the drainage position of the SAV of Trolard into the superior sagittal sinus. Anastomotic veins were defined as veins that connect veins in different drainage areas. The

Morphometry of Superficial Cerebral Veins 105

Fig. 2. Photograph showing the superficial cerebral veins injected with liquid polyvinyl

acetate with blue dye and polymerized with water.

SAV of Trolard or IAV of Labbe was defined as the largest vein of the superior or inferior cerebral veins that connect the SMCV to the superior sagittal sinus or the transverse sinus. The central sulcal vein (CSV) was defined as a vein that runs along the central sulcus, and

may be identical to the SAV. It gathers venous blood from the parts of the precentral and

postcentral gyri bordering the central sulcus and ascends along the central sulcus to drain into the superior sagittal sinus. Superficial cerebral veins were classified into eight types according to the predominance

of the anastomotic veins: (1) type la, predominant SMCV (Sylvius); (2) type Ib, predominant

SAV (Trolard); (3) type Ic, predominant IAV (Labbe); (4) type IIa, both SAV and IAV

predominant; (5) type Ilb, both SMCV and IAV predominant; (6) type IIc, both SMCV and SAV predomiant; (7) type III, balanced between SMCV, SAV, and IAV; and (8) type IV, rare or absent anastomotic veins.

We introduced an evaluation method using a proportional numbering system for the numbers of superior cerebral veins. Because identifying all superior cerebral veins, includ-ing fine veins, under macroscopic observation is difficult unless the necessary material has been completely injected, we made use of proportional numbers by sizes of veins for venous distribution compared with the number of occipital superior cerebral veins, instead of the absolute number of veins. This was because occipital superior cerebral veins were the fewest and varied the least among superior cerebral veins.


For photographic purposes, superficial cerebral veins in several cadavers were injected one by one with liquid polyvinyl acetate containing blue dye with a syringe connected to a fine flexible catheter (Fig. 2).

Results

The average brain weight was 1,187 g (range, 810 to 1,840 g). The average lengths of

FO, FC, and FP were 229.5•}12.7 mm, 126.3•}12.4 mm and 192.2•}12.4 mm, respectively.

The percentile value of FC lengths to FO lengths and of FO was 55.0±4.3% and 83.6•}

3.7%, respectively. The average distance in a straight line of FOD and FPOD was 155.3•}

7.2 mm and 118.9•}7.6 mm (76.6•}4.0% of FOD), respectively (Fig. 1).

Superficial cerebral veins run in the arachnoid network of the subarachnoid space and

partially follow along sulci. According to our observation, SMCV, SAV, and IAV were

each classified into 4 types (Table 1).

Among the 122 brains, the SMCV was observed in 121 on the left hemisphere (LH),

and in 117 on the right hemisphere (RH) (Table 2). The type frequency of the SMCV was

as follows: (a) left predominant, 29 (23.8%); (b) right predominant, 13 (10.7%); and (c)

no laterality, 80 (65.6%); and (d) absent, 0 (0.0%) (Table 1). The SAV was present on

the left side in 72 brains and on the right side in 67 brains (Table 2). Three brains (1.2%)

had two SAVs, one (0.4%) had three SAVs. The type frequency of the SAV was as follows:

(a) left predominant, 34 (27.9%); (b) right predominant, 29 (23.8%); (c) no laterality, 27

(22.1 %); and (d) absent, 32 (26.2%) (Table 1). The IAV was observed on the left side in

79 brains and on the right side in 51 brains (Table 2). None of the brains had more than

Table 1. Drainage lateralities of the superficial cerebral veins (in 122 cadavers).

IAV: inferior anastomotic vein (Labbe); L: left; R: right; SAV: superior anastomotic vein (Trolard); SMCV: superficial middle cerebral vein (Sylvius).

Table 2. Frequencies of the superficial cerebral veins (in 244 hemispheres).

CSV: central sulcal vein (Rolando), See Table 1 for other abbreviations.


Table 3. Drainage positions of the superior anastomotic vein (of Trolard)

in 122 cadavers.

CS: central sulcus; L: left; R: right.

Table 4. Classification of the superficial cerebral veins (in 244 hemispheres).

The explanation of types is given in the text and in Fig. 3.

one IAV of Labbe. The type frequency of the IAV was as follows: (a) left predominant, 54 (44.3%); (b) right predominant, 27 (22.1 %); (c) no laterality, 12 (9.8%); and (d) absent, 29 (23.8%) (Table 1).

In the 122 brains observed, the frequencies of location of the SAY of Trolard were as follows: (a) anterior to the central sulcus in 16 LHs (13.1 %) and in 21 RHs (17.2%); (b) along the central sulcus in 23 LHs (18.9%) and 15 RHs (12.3%); and (c) posterior to

the central sulcus in 34 LHs (27.9%) and 31 RHs (25.4%) (Table 3). According to our data, the location of the SAY of Trolard can be noted in the order of (a) posterior to,

(b) along, and (c) anterior to, the central sulcus.The CSV was observed on the LH in 79 cases (64.8%) and on the RH in 80 case (65.6%)

(Table 2). Its average diameter was 2.7 mm (range, 1.0 to 5.0 mm) near the superior sagittal sinus. The frequency of each of the eight types among the 122 brains is listed in Table 4 and

the schema of each type is shown in Fig. 3. According to our data, the superficial cerebral veins can be described by the total type frequencies in the order of: (1) type IIc in 24 LHs

(19.7%) and 42 RHs (34.2%); (2) type III in 34 LHs (27.9%) and 24 RHs (19.7%); and (3) type lib in 29 LHs (23.8%) and 19 RHs (15.6%). From the viewpoint of the type frequencies, the venous anastomoses are in the order of: type III, type IIb, and type IIc on the left side and type IIc, type III, and type IIb on the right side.

Superior cerebral veins were most frequently observed on the frontal and parietal lobes. There were few on the occipital lobe. Following an inferior cerebral vein on the temporal lobe macroscopically was sometimes very difficult. According to the criteria of venous size


described above, venous distributions were evaluated from lobe to lobe. On the frontal

lobe, small or medium veins were most frequently observed on the left, while large veins

were most frequent on the right. On the parietal and occipital lobes, small veins were abun-dant on the left, while medium or large veins were most frequently observed on the right. As far as whole superior cerebral veins are concerned, rather slender veins, such as small

and medium veins, were more frequent on the left side than on the right, while thick veins

(large veins) were observed more frequently on the right than were other sizes. As for the number of superior cerebral veins concerned, the average was small, 0.98; medium, 3.9; and large, 2.0 on the LH, and small, 0.74; medium, 3.9; and large, 2.1 on the RH. The

proportional number of veins per lobe was assessed on the basis of veins on the occipital lobe. On the frontal lobe, the proportional number was small, 2.5; medium, 4.0; and large,

7.7 on the LH and small, 2.1; medium, 3.2; and large, 5.8 on the RH. On the parietal lobe, it was small, 1.1; medium, 3.0; and large, 6.5 on the LH, and small, 0.8; medium, 3.1; and large, 5.4 on the RH.

Discussion

In spite of its clinical importance, the relationship of the locations of superficial cerebral

veins and cerebral sulci remains unknown. We performed an anatomic study of the location of superficial cerebral veins in relation to cerebral sulci to obtain precise knowledge of venous drainage, so that the relationship between veins and cerebral sulci could be more easily judged from venograms.

First, we identified the central sulcus and parieto-occipital sulcus and measured the half-

perimeters from the frontal pole to these points on a lateral view. The proportion of FC to FO was 55% near the midline. In other words, the central sulcus near the midline is located slightly behind the midpoint of the half-perimeter from the frontal pole to the oc-cipital pole. The proportion of FP to FO was about 84% . The parieto-occipital sulcus, :which lies mainly in the medial side of the cerebral hemisphere between the parietal and occipital , lobes, is located within one fifth of the FO perimeter from the occipital pole.

Using the knowledge of perimeter or distance proportions described above (FC, FP, FOD, and FPOD), one can easily determine the area of each lobe with plain X-rays, angiography,

computed tomography, or magnetic resonance imaging. There were considerable variations in the size and position of all individual cortical veins, even among those on opposite hemispheres of the same brain, and not only for the three main drainage veins: SAVs, IAVs and SMCVs. According to cerebral angiographic data re-

ported by Di Chiro2,4), the vein of Trolard predominates on the dominant hemisphere, while the vein of Labbe predominates on the nondominant hemisphere. He discovered through cerebral angiography a left-side dominance of the vein of Labbe in 55% of cases and of the vein of Trolard in 18.4% of cases; right-side dominance was found in 24.6% and 46%, respectively. Delmas et al.2,5) observed a similar difference in superficial cerebral veins from bilateral phlebograms in 175 cases. Their data showed the vein of Labbe was distinctly larger on the left side in 42% of cases and on the right side in 21 %. The vein of Trolard was distinctly larger on the left in 24% of cases and on the right in 52% of caess2,5,6). We conducted a similar study, using 122 cadaveric brains. In our present study the left-side IAV dominance was slightly less (44.3%) than that reported by Delmas et al. (55%). On the SAV too, there was a slight difference in dominance frequency between our data (27.9%)


and the angiographic data of Delmas et al. (18.4%). No angiographic data have been re-

ported for the SMCV, but our anatomic data showed a left-side dominance of 23.8%. There are no angiographic data regarding absent types either, although they were obviously

anatomically present. In Di Chiro's study of the hemispheric incidence of predominant superficial pathways of venous drainage, the superficial venous channel on the left hemisphere was the vein of Labbe, equivalent to our type Ic, while the vein of Trolard , equivalent to our type Ib, predominated on the right4). If we compare our venous anastomotic types with

angiographic venous drainage pathways, we notice anatomically proved cases with more than two main superficial venous channels, such as type II or type III , occur more frequently than with angiographic observations. Even when veins are anatomically present , they can not always be filled with contrast medium so as to appear on angiography . The reason for this could be a problem connected to hemodynamic balance . The frequencies of the CSV were so high that they were observed bilaterally in about 65% of cases. We should keep in mind that one third of cases were without CSV and one fourth of cases were without the SAV. The diameters of the CSV ranged from 1.0 to 5.0 mm (average, 2.7 mm). On the basis of our calculation of a 55% perimeter proportion of FC to F0, frontal lobe veins can be easily distinguished from parietal lobe veins with angiography . Several textbooks7' describe the vein of Trolard as being located along a certain sulcus, for example, the pre-central sulcus. However, we found that it was not always true . Consequently, it is impor-tant to realize that the position of the SAV of Trolard is not always fixed to a certain sulcus.

According to our observation, there were at least three kinds of drainage positions for the SAV of Trolard: anterior to the central sulcus (mostly along the central sulcus, and posterior to the central sulcus (mostly along the postcentral sulcus). Regarding the drainage

positions of the SAV of Trolard, posterior to the central sulcus was most common. Angio-

graphic studies have not mentioned the drainage position into the superior sagittal sinus in relation to the location of the central sulcus, although this is an important element for

preoperative evaluation. From the viewpoint of venous drainage, we can classify the super-ficial cerebral veins into eight groups, as mentioned above (Fig . 3). Of them, type IIc was the most frequent. As far as laterality is concerned , type III was most frequent on the left, and type IIc on the right. Rare anastomotic vein groups , such as type IV or type I, were found more frequently in older brains. This finding supports the view that hemorrhagic infarction in the aged might occur more frequently than in a young person when the birdg-ing vein is sacrificed during an operation. In other words, the small bridging veins can be sacrificed if necessary, as there are abundant collateral veins, such as type II or type III.

Small superior cerebral veins were the most frequent on the frontal lobe. Occipital su-perior cerebral veins were the least common. It is natural that the lobe with the fewest veins is the most favorable for surgical operations . These data are important for investi-gating cerebral blood flow and for solving problems in the future.

It is well known that special care must be taken of the superior cerebral vein on the frontal lobe during an interhemispheric surgical approach . According to our study, the shortest distance from the most lateral part of the bridging vein to the midline was 25 mm . This information is of the utmost importance to avoid venous damage when we open the dura mater during a surgical operation.

Finally, when we analyze the venous phase on cerebral angiograms, it is extremely im-

portant to understand the anatomy of the veins, especially for operations on arteriovenous


Fig. 3. Diagrams illustrating superficial cerebral veins and their classifications (lateral views). Type Ia: predominant superficial middle cerebral vein (Sylvius); type Ib: predominant

superior anastomotic vein (Trolard); type Ic: predominant inferior anastomotic vein (Labbe); type ha: predominant superior and inferior anastomotic veins (Trolard and

Labbe); type IIb: predominant superficial middle cerebral (Sylvius) and inferior anastomotic (Labbe) veins; type IIc: predominant superficial middle cerebral (Sylvius) and superior anastomotic (Trolard) veins; type III: balanced between the superficial middle cerebral (Sylvius), superior anastomotic (Trolard) and inferior anastomotic (Labbe) veins; type IV: rare anastomotic veins. CS: central sulcus; FL: frontal lobe; FP frontal pole; LS: lateral sulcus; OL: occipital lobe; OP: occipital pole; PL: parietal lobe; PON: preoccipital notch; POS: parleto-occipital sulcus; TL: temporal lobe.


malformations, brain tumors (for example, f alx meningiomata) and other intracranial dis-

orders, given the possibility of structural displacement. Precise anatomical knowledge of

the cerebral veins can foster accurate comprehension of diseases, therapies and outcomes.

Acknowledgements

The authors wish to thank Prof. Hiroshi Yamashita, Department of Anatomy, Jikei Medical College for

his encouragement during the present study.

References

1) Crosby EC, Humphrey T and Lauer EW: Cerebral veins. In: Correlative Anatomy of the Nervous System, The Macmillan Co., New York, pp 565-571 (1962) 2) Krayenbi hl HA and Yasargil MG: The cerebral veins. In: Cerebral angiography, George Thieme

Verlag, New York, pp 181-251 (1982) 3) Newton TH and Potts DG: Superficial supratentorial veins and dural sinuses. In: Radiology of

the Skull and Brain Angiography, The C. V. Mosby Co., Saint Louis, Vol. Two/Book 3, pp 1851-1902 (1974)

4) Di Chiro G: Angiographic pattern of cerebral convexity veins and superficial dural sinuses. Am J Roentgenol, 87: 308-321 (1962)

5) Delmas A, Pertuiset B and Bertrand G: Les veines du lobe temporal. Rev Otoneuroophthalmol (Paris), 23: 224-230 (1951)

6) Oka K, Rhoton AL Jr, Barry M and Rodriguez R: Microsurgical anatomy of the superficial veins of the cerebrum. Neurosurgery, 17: 711-748 (1985)

7) Ohta T, Matsutani M, Aruga T, Onomura T, Manaka S and Nishimura S: Cerebral Angiography. In: Neurosurgery, Kinpodo, Kyoto, pp 327-344, 899 (1991) (in Japanese)

[Received November 29, 1995: Accepted January 22, 1996]

morphometric anatomy of superficial cerebral veins

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