Article abstract
Bilateral intracranial arteriograms of 123 right-handed patients and 38 left-handedpatientswere evaluatedfor: (1) the angulationof the branches of the right and left middle cerebral arteries as they leave the Sylvian fissure, (2) the position of the posterior saggital sinus with respect to the anatomic saggital midline, and (3) the dominant right-sided and left-sided superficial cortical venous drainage (Labbe, Trolard, and Sylvian). Arteriographic evaluations of these points may prove useful in assessing cerebral dominance.
Arte riographic Gorrelates of handedness FRED H. HOCHBERG, M.D., and MARJORIE LE MAY, M.D.
S
ignificant differences have been noted recently in the arteriographic position of the right and left middle cerebral arteries (LeMay and Culebras, 1972l). The angles formed by the posterior sylvian branches of the right middle cerebral artery as they leave the Sylvian fissure were reported to be wider on the right in 38 of 44 unselected right-handed patients. Only three of 18 left-handed individuals showed wider angles on the right. The present study of patients with known handedness was an attempt to determine the functional implications of differences in angulation of the distal Sylvian fissure branches of the middle cerebral arteries. Differences in the flow of the venous channels also were noted and correlated with the arterial pattern.
Methods. Carotid arteriograms performed as part of diagnostic evaluation at several Boston hospitals were collected and evaluated. In each instance the patient’s handedness was known. Carotid arteriograms consisted of bilateral studies performed via the percutaneous or retrograde femoral approaches. All films were evaluated by the two authors. Excluded were patients with gross mass lesions, known major intracranial arterial occlusions, or technically inadequate studies. ~~
~
From Harvard Medical School and the Departments of Neuropathology and Radiology, Massachusetts General Hospital, Boston This work was supported in part by NINDS special fellowship No 1 F11 NS 2578-01 Received for publication September 9, 1974 Dr Le Mays address is Department of Radiology, Massachusetts General Hospital, Fruit Street, Boston, MA 02114
218
NEUROLOGY 25: 218-222, March 1975
Handedness. Each patient or family member was contacted and questioned concerning his dominant hand, eye, and foot. Where hand usage varied according to task (i.e., cutting, kicking, writing, throwing a ball), the preferred hand was considered that which the patient used for writing and cutting food. Sylviun point angulutiorr. The branches of the middle cerebral arteries within the Sylvian fissure were identified i n the frontal projection. The most medial margin of the last branch leaving the Sylvian fissure was identified as the “sylvian point” (Taveras and Wood, 19642). The vessel forming the sylvian point leaves the Sylvian fissure by passing under the parietal operculum. A second point, x, was marked on this vessel 1 cm lateral to the sylvian point, (figure 1). The sylvian point angle was defined as the angle formed by line SX and vertical line SO, as in figure 1. Line SO is drawn through the sylvian point and forms a perpendicular with the superior orbital line. This is not an absolute angle but allows for comparison of the position of the vessels leaving the Sylvian fissure on the right and left sides. Venous druinage. 1. Superior longitudinal sinus. The posterior portion of the superior longitudinal sinus was identified on the frontal projection. The middle of the superior longitudinal sinus was marked at a point 3 cm above the torcule Herophilae (figure 2). The distance of this point from the midline of the cranial vault was noted. I n cases where the posterior end of the superior longitudinal sinus was represented by two channels, the point equidistant between them was chosen as the midpoint. 2. Transverse sinus. The transverse sinuses were
Figure 1. Anterior-posterior view of carotid arteriogram showing the sylvian point angle formed by lines SX and SO.
identified on frontal projections and the drainage into the two sinuses as well as their vertical locations were compared. 3. Superficial cerebral veins. The major superficial cerebral venous channels (Trolard, Labbt, and Sylvian) were identified in both the right and left hemispheres. The predominant vessels draining the two hemispheres were noted.
Results. Arteriograms from 159 patients were studied. There were 123 right-handed patients (66 male) and 36 left-handed patients (27 male). Two of the left-handers were from a veteran’s hospital where the patients are predominantly male, but the other patients were from general hospitals in which there is no significant sex differential i n the population. The mean age of the right-handed patients was 5 1 years (male 53, female 49) and the mean age of the left-handed patients was 44 years. The arteriograms were not normal in every case but abnormalities were not marked and were restricted to areas not under consideration. Diagnosis included thrombotic or embolic infarcts (23), transient ischemic attacks (8), aneurysms ( 1 3 , small subdurals (4), tumors (3,dementia (S), and injury (4). Sylviun point ungles in right-handed putients. The sylvian point angles were determined bilaterally in 106 right-handed patients, 53 male and 53 female (table I ) . In 71, the right hemispheric sylvian point angle was greater than the left hemispheric sylvian point angle by more than 10 degrees. Twenty-seven of the 106 patients had
Figure 2. Schematic representation of the superior longitudinal sinus (SLS)and the transverse sinus (TS) illustratingthe point of measurement of the SLS position.
NEUROLOGY March 1975 219
Arteriographic correlates of handedness
Table 1. Right-sided (R) versus left-sided (L) sylvian point angulation (SPA) in right-handersand left-handers
Table 2. Position of midpoint of lower end of superior longitudinal sinus
comparatively equal right and left sylvian point angles, and eight had greater angulation on the left than on the right. There was no distinct relationship between sylvian point angle and the patients’ sex. The mean right sylvian point angle for the right-handed patients was 93 degrees versus 69.5 degrees for the left sylvian point angle. The mean difference between the right and left sylvian point angle was 23.5 degrees. The mean right sylvian point angle in right-handed patients less than 30 years old was 104 degrees versus 9 I . 8 degrees for individuals above 30 years. The left sylvian point angle in the group under 30 years was 84 degrees versus 68.1 degrees for those above 30 years. It is uncertain whether these differences are significant.
Table 3. The relationship between right-side sylvian point angulation (RSPA) and left-side sylvian point angulation (LSPA) and sagittal sinus position in right-handed and left-handed males and females
220
NEUROLOGY March 1975
Sylvian point angles in left-handed patients. The sylvian point angles were determined bilaterally in 28 left-handed patients. In only six patients was the right sylvian point angle greater than the left by more than 10 degrees (table I ) . In 20 of the patients the right and left sylvian point angles were within 10 degrees. The mean difference of the right-sided and left-sided sylvian point angle was 6.6 degrees. Acknowledged right-handers have significantly greater differences between right-sided and left-sided sylvian point angles than do left-handers. Insufficient data is available on the relationship between age and sylvian point angle in left-handed patients. Position qf the lower end of the superior longitutlinal sinus. The position of the midpoint of the superior longitudinal sinus measured 3 cm above the torcula was noted in 123 right-handed and 33 left-handed patients. In two cases the superior longitudinal sinus was divided at its posterior end and the point equidistant from both was marked as the midpoint. The superior longitudinal sinus was found to be to the right of the midline in 50 percent of right-handers and 40 percent of left-handers (table 2). It was to the right in 53 percent of males and 47 percent of females. The positions of the superior longitudinal sinus and both sylvian point angles were noted in 137 patients (2 1 left-handed and 1 16 right-handed). Table 3 indicates the position of the lower end of the superior longitudinal sinus in relation to the right versus left sylvian point angle in these individuals. Sixty-two percent of the 55 patients in whom there was less than a 10 degree difference between right and left sylvian point angles (group B , table 3), or in whom left sylvian point angle was greater than right sylvian point angle by more than 10 degrees (group C, table 3 ) , had their sagittal sinus in the midline or to the left of the midline. Forty-two of the 63 patients (67 percent) with the sagittal sinus to the right of the midline had their right sylvian point angle greater than the left sylvian point angle by over 10 degrees. In contrast, 40 of 74 patients (54 percent) with an superior longitudinal sinus in the midline or to the left of the midline had their right sylvian point angle greater than their left sylvian point angle by more than 10 degrees. Transverse sinus. 1. Major flow. The major transverse sinus recipient of superior longitudinal sinus flow was determined in 1 1 1 patients (101 right-handed and 10 left-handed). The main flow was to the right in 61 percent
of patients (table 4). No significant relationship existed between transverse sinus flow and handedness, sex, or sylvian point angle difference. 2. Relative vertical position. The relative vertical position of the right and left transverse sinuses could be determined in 118 patients (16 left-handers). Fifty-five of the 102 right-handed persons (54 percent) had the right transverse sinus above their left. In left-handed individuals 11 of 16 (69 percent) had transverse sinuses of equal height, or the left was above the right. There was no significant relationship between sylvian point angle difference, sex, and relative vertical transverse sinus position. Superficial cerebral venous circulation. The main draining veins were determined bilaterally in 114 patients, 101 right-handed and 13 left-handed (table 5). In right-handed persons, irrespective of sex or the difference in sylvian point angles, Trolard was the major draining vein in the right hemisphere in 3 1 percent and on the left in 20 percent. Labbe was the prominent draining vein in the left hemisphere in 32.7 percent and on the right in 15 percent. Trolard was involved in the right hemispheric drainage in 72 percent of the right-handers (versus 53 percent for Labbe). Seventy-one percent of the right-handers had significant Labbe drainage of the left hemisphere versus 61 percent for Trolard. Sylvian drainage was not significant in either hemisphere. Data on left-handers was insufficient to draw conclusions (table 5 ) . There was no relationship between right and left hemisphere superficial venous drainage and sylvian point angle differences in both right-handers and left-handers.
Table 4. Major transverse sinus flow correlated with (right-side versus left-side) sylvian point angle (R:L SPA) difference in right-handers and left-handers
Table 5. Major right and left hemispheric draining veins in right-handers and left-handers
NEUROLOGY March 1975 221
Arteriographic correlates of handedness
Discussion. Despite the extensive literature dealing with hemispheric functional differences, little has been written about morphologic hemispheric differences. Physical anthropologists have indirectly appreciated such differences by noting asymmetries in the cranial vault. Inglessis ( 1 9253), Kavue ( I 93 14), and Gundara and Zivanovic ( 1968*) noted that the impression on the vault caused by the occipital lobes was two to four times more often deeper on the left than on the right. This indicated a greater length of the left hemisphere than of the right. Smith (19076) pointed out that the "area striata" (posterior parietal-occipital cortex) was significantly greater on the left side in 10 brains studied. I n g l e s ~ i sin , ~a large series of brains obtained from a mental institution, noted that in 63.5 percent the left cerebral hemisphere weighed more than' the right and that in 66.8 percent the left lateral ventricle had a greater capacity. McRae, Branch, and Milner (1968') reported finding statistically significant hemispheral differences in the occipital horns of the lateral ventricles. In right-handed individuals with asymmetrical occipital horns, the left occipital horn was five times more often larger than the right. In left-handed persons showing asymmetry in the occipital horns, there was an equal chance of the right or left occipital horn being longer. The present study confirms the earlier report of predictable hemispheral differences in the middle cerebral arteries as they leave the Sylvian fissures. In 67 percent of right-handed individuals in the present study, the angle formed by the vessels leaving the posterior end of the Sylvian fissure was greater on the right than on the left by over 10 degrees. The mean difference between right and left sylvian point angles was 23.5 degrees. In only 21.4 percent of left-handed persons, on the other hand, was the right sylvian point angle larger than left by over 10 degrees. The mean difference between the right and left sylvian point angles was 6.6 degrees. The differences in the branches of the right and left middle cerebral arteries leaving the distal end of the Sylvian fissures reflect the anatomic differences in the right and left Sylvian fissures. These differences were noted by Cunningham (18928), who showed that the posterior end of the right Sylvian fissure was commonly higher than the left, reflecting the fact that the right parietal operculum is commonly smaller than the left. In addition, Geschwind and Levitsky (196g9) found that the planum temporale was larger on the left than on the right in 65 of 100 brains, and larger on the right in only 1 1 brains. These hemispheral differences in the Sylvian fissures are present in fetal life (Cunningham, 1892R; LeMay and Culebras, 1972l). Just as the greater bulk of the left parietal operculum appears to be reflected by the smaller left sylvian point angle, the distal superior sagittal sinus appears to be influenced by the relative bulk of the right and left occipital poles. This occipital pole asymmetry was first noted by Smith6 and was extended by Inglessis,3 who showed that the superior longitudinal sinus bends to the right in 60 percent of brains. Streeter (1 9 15l o ) has reported this preferential position in a 20 mm embryo. In our study, the most common position of the 222
NEUROLOGY March 1975
end of the sagittal sinus was to the right of the midline. In addition, the transverse sinus was higher on the right in 54 percent of right-handed patients versus only 3 1 percent of left-handed patients. This reflects the greater bulk of the posterior portion of the left hemisphere in right-handed patients. A relationship appears to exist between sylvian point angulation and the position of the posterior e'nd of the superior longitudinal sinus. The posterior end of the superior longitudinal sinus tended to be in the midline or to the left of the midline in patients with nearly equal sylvian point angles than in patients with right sylvian point angle larger than left sylvian point angle. The superficial veins of the brain have been the subject of several studies (Wold, 196311; DiChiro, 196212; Matsubara, 19611 3 ; Gvozdanovic, 195614). Changes in flow pattern in these vessels are common in pathologic situations."~13~14 Since most of the studies are in patients with disease, it is difficult to be certain of the venous flow in normal brains. We found, as have others,13 that the drainage on the two sides of the brain tends to be similar. DiChiroI2 correlated the superficial draining veins with cerebral dominance. In 53 percent of his patients with left hemispheral dominance by Wada test, the dominant draining of the left hemisphere was the vein of Labbe, while in 66 percent of patients with right cerebral dominance Labbe was the dominant vein of the right. In our study 32.7 percent of the right-handed patients had Labbe as the prominent draining vein of the left hemisphere and 15 percent had Labbe as the prominent vein of the right hemisphere. The number of left-handed patients in our study in whom superficial venous drainage could be determined was too small to be of significance. REFERENCES 1. LeMay M, Culebras A: Human brain - morphologic differences in the hemispheresdemonstrableby carotid arteriography.N Engl J Med 287:168-170, 1972 2. Taveras JM, Wood EH: Diagnostic Neuroradiology. Baltimore, The Williams & Wilkins Company, 1964 3. lnglessis M: Uber Katazitasul-evscheideder linken und rechten Halfte am Schadel bei Menschen uber Hirn asymmetrian. ZGes Neurol Psych 97:354-373, 1925 4. Kavue I: Normale assymetrie des menschildchen Schadels. Phil dissertation, Berlin-Leipzig, quoted in Gundara5, 1968 5. Gundara N, Zivanovic S: Asymmetry in East African skulls. Am J Phys Anthropology 28:331-338, 1968 6. Smith GE: On the asymmetry of the caudal poles of the cerebral hemispheres and its influence on the occipital bone. Anat Anz 30:574-578, 1907 7. McRae DL, Branch CL, Milner B: The occipital horns and cerebral dominance. Neurology (Minneap) 18:95-98, 1968 8. Cunningham DJ: Contribution to the Surface Anatomy of the Cerebral Hemispheres. Dublin, Royal Irish Academy, 1892 9. Geschwind N. Levitsky W: Human brain: Left-right asymmetries in temporal speech region. Science 161:I 86-187, 1968 10. Streeter GL: Venous sinuses of the dura mater. Am J Anatomy 181145-178,1915 11. Wold BS, Huang YP, Newman CM: The superficial sylvian venous drainage system. Am J RoentgenolRadium Ther Nucl Med 49:398-410, 1963 12. DiChiro G: Angiographic patterns of cerebral convexity veins and superficial dural sinuses. Am J Roentgenol Radium Ther Nucl Med 87:308-321, 1962 13. Matusubara T: An observation on cerebral phlebograms with special reference to the changes in superficial veins. Nagoya J Med Sci 23186-94,1961 14. Gvozdanovic V: Changes in the superficial veins in cases of intracranial expanding processes. Acta Radio146:195-202, 1956
Arteriographic correlates of handedness FRED H. HOCHBERG and MARJORIE LE MAY Neurology 1975;25;118 DOI 10.1212/WNL.25.3.118 This information is current as of March 1, 1975 Updated Information & Services
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Neurology ® is the official journal of the American Academy of Neurology. Published continuously since 1951, it is now a weekly with 48 issues per year. Copyright © 1975 by the American Academy of Neurology. All rights reserved. Print ISSN: 0028-3878. Online ISSN: 1526-632X.
Bilateral intracranial arteriograms of 123 right-handed patients and 38 left-handedpatientswere evaluatedfor: (1) the angulationof the branches of the right and left middle cerebral arteries as they leave the Sylvian fissure, (2) the position of the posterior saggital sinus with respect to the anatomic saggital midline, and (3) the dominant right-sided and left-sided superficial cortical venous drainage (Labbe, Trolard, and Sylvian). Arteriographic evaluations of these points may prove useful in assessing cerebral dominance.
Arte riographic Gorrelates of handedness FRED H. HOCHBERG, M.D., and MARJORIE LE MAY, M.D.
S
ignificant differences have been noted recently in the arteriographic position of the right and left middle cerebral arteries (LeMay and Culebras, 1972l). The angles formed by the posterior sylvian branches of the right middle cerebral artery as they leave the Sylvian fissure were reported to be wider on the right in 38 of 44 unselected right-handed patients. Only three of 18 left-handed individuals showed wider angles on the right. The present study of patients with known handedness was an attempt to determine the functional implications of differences in angulation of the distal Sylvian fissure branches of the middle cerebral arteries. Differences in the flow of the venous channels also were noted and correlated with the arterial pattern.
Methods. Carotid arteriograms performed as part of diagnostic evaluation at several Boston hospitals were collected and evaluated. In each instance the patient’s handedness was known. Carotid arteriograms consisted of bilateral studies performed via the percutaneous or retrograde femoral approaches. All films were evaluated by the two authors. Excluded were patients with gross mass lesions, known major intracranial arterial occlusions, or technically inadequate studies. ~~
~
From Harvard Medical School and the Departments of Neuropathology and Radiology, Massachusetts General Hospital, Boston This work was supported in part by NINDS special fellowship No 1 F11 NS 2578-01 Received for publication September 9, 1974 Dr Le Mays address is Department of Radiology, Massachusetts General Hospital, Fruit Street, Boston, MA 02114
218
NEUROLOGY 25: 218-222, March 1975
Handedness. Each patient or family member was contacted and questioned concerning his dominant hand, eye, and foot. Where hand usage varied according to task (i.e., cutting, kicking, writing, throwing a ball), the preferred hand was considered that which the patient used for writing and cutting food. Sylviun point angulutiorr. The branches of the middle cerebral arteries within the Sylvian fissure were identified i n the frontal projection. The most medial margin of the last branch leaving the Sylvian fissure was identified as the “sylvian point” (Taveras and Wood, 19642). The vessel forming the sylvian point leaves the Sylvian fissure by passing under the parietal operculum. A second point, x, was marked on this vessel 1 cm lateral to the sylvian point, (figure 1). The sylvian point angle was defined as the angle formed by line SX and vertical line SO, as in figure 1. Line SO is drawn through the sylvian point and forms a perpendicular with the superior orbital line. This is not an absolute angle but allows for comparison of the position of the vessels leaving the Sylvian fissure on the right and left sides. Venous druinage. 1. Superior longitudinal sinus. The posterior portion of the superior longitudinal sinus was identified on the frontal projection. The middle of the superior longitudinal sinus was marked at a point 3 cm above the torcule Herophilae (figure 2). The distance of this point from the midline of the cranial vault was noted. I n cases where the posterior end of the superior longitudinal sinus was represented by two channels, the point equidistant between them was chosen as the midpoint. 2. Transverse sinus. The transverse sinuses were
Figure 1. Anterior-posterior view of carotid arteriogram showing the sylvian point angle formed by lines SX and SO.
identified on frontal projections and the drainage into the two sinuses as well as their vertical locations were compared. 3. Superficial cerebral veins. The major superficial cerebral venous channels (Trolard, Labbt, and Sylvian) were identified in both the right and left hemispheres. The predominant vessels draining the two hemispheres were noted.
Results. Arteriograms from 159 patients were studied. There were 123 right-handed patients (66 male) and 36 left-handed patients (27 male). Two of the left-handers were from a veteran’s hospital where the patients are predominantly male, but the other patients were from general hospitals in which there is no significant sex differential i n the population. The mean age of the right-handed patients was 5 1 years (male 53, female 49) and the mean age of the left-handed patients was 44 years. The arteriograms were not normal in every case but abnormalities were not marked and were restricted to areas not under consideration. Diagnosis included thrombotic or embolic infarcts (23), transient ischemic attacks (8), aneurysms ( 1 3 , small subdurals (4), tumors (3,dementia (S), and injury (4). Sylviun point ungles in right-handed putients. The sylvian point angles were determined bilaterally in 106 right-handed patients, 53 male and 53 female (table I ) . In 71, the right hemispheric sylvian point angle was greater than the left hemispheric sylvian point angle by more than 10 degrees. Twenty-seven of the 106 patients had
Figure 2. Schematic representation of the superior longitudinal sinus (SLS)and the transverse sinus (TS) illustratingthe point of measurement of the SLS position.
NEUROLOGY March 1975 219
Arteriographic correlates of handedness
Table 1. Right-sided (R) versus left-sided (L) sylvian point angulation (SPA) in right-handersand left-handers
Table 2. Position of midpoint of lower end of superior longitudinal sinus
comparatively equal right and left sylvian point angles, and eight had greater angulation on the left than on the right. There was no distinct relationship between sylvian point angle and the patients’ sex. The mean right sylvian point angle for the right-handed patients was 93 degrees versus 69.5 degrees for the left sylvian point angle. The mean difference between the right and left sylvian point angle was 23.5 degrees. The mean right sylvian point angle in right-handed patients less than 30 years old was 104 degrees versus 9 I . 8 degrees for individuals above 30 years. The left sylvian point angle in the group under 30 years was 84 degrees versus 68.1 degrees for those above 30 years. It is uncertain whether these differences are significant.
Table 3. The relationship between right-side sylvian point angulation (RSPA) and left-side sylvian point angulation (LSPA) and sagittal sinus position in right-handed and left-handed males and females
220
NEUROLOGY March 1975
Sylvian point angles in left-handed patients. The sylvian point angles were determined bilaterally in 28 left-handed patients. In only six patients was the right sylvian point angle greater than the left by more than 10 degrees (table I ) . In 20 of the patients the right and left sylvian point angles were within 10 degrees. The mean difference of the right-sided and left-sided sylvian point angle was 6.6 degrees. Acknowledged right-handers have significantly greater differences between right-sided and left-sided sylvian point angles than do left-handers. Insufficient data is available on the relationship between age and sylvian point angle in left-handed patients. Position qf the lower end of the superior longitutlinal sinus. The position of the midpoint of the superior longitudinal sinus measured 3 cm above the torcula was noted in 123 right-handed and 33 left-handed patients. In two cases the superior longitudinal sinus was divided at its posterior end and the point equidistant from both was marked as the midpoint. The superior longitudinal sinus was found to be to the right of the midline in 50 percent of right-handers and 40 percent of left-handers (table 2). It was to the right in 53 percent of males and 47 percent of females. The positions of the superior longitudinal sinus and both sylvian point angles were noted in 137 patients (2 1 left-handed and 1 16 right-handed). Table 3 indicates the position of the lower end of the superior longitudinal sinus in relation to the right versus left sylvian point angle in these individuals. Sixty-two percent of the 55 patients in whom there was less than a 10 degree difference between right and left sylvian point angles (group B , table 3), or in whom left sylvian point angle was greater than right sylvian point angle by more than 10 degrees (group C, table 3 ) , had their sagittal sinus in the midline or to the left of the midline. Forty-two of the 63 patients (67 percent) with the sagittal sinus to the right of the midline had their right sylvian point angle greater than the left sylvian point angle by over 10 degrees. In contrast, 40 of 74 patients (54 percent) with an superior longitudinal sinus in the midline or to the left of the midline had their right sylvian point angle greater than their left sylvian point angle by more than 10 degrees. Transverse sinus. 1. Major flow. The major transverse sinus recipient of superior longitudinal sinus flow was determined in 1 1 1 patients (101 right-handed and 10 left-handed). The main flow was to the right in 61 percent
of patients (table 4). No significant relationship existed between transverse sinus flow and handedness, sex, or sylvian point angle difference. 2. Relative vertical position. The relative vertical position of the right and left transverse sinuses could be determined in 118 patients (16 left-handers). Fifty-five of the 102 right-handed persons (54 percent) had the right transverse sinus above their left. In left-handed individuals 11 of 16 (69 percent) had transverse sinuses of equal height, or the left was above the right. There was no significant relationship between sylvian point angle difference, sex, and relative vertical transverse sinus position. Superficial cerebral venous circulation. The main draining veins were determined bilaterally in 114 patients, 101 right-handed and 13 left-handed (table 5). In right-handed persons, irrespective of sex or the difference in sylvian point angles, Trolard was the major draining vein in the right hemisphere in 3 1 percent and on the left in 20 percent. Labbe was the prominent draining vein in the left hemisphere in 32.7 percent and on the right in 15 percent. Trolard was involved in the right hemispheric drainage in 72 percent of the right-handers (versus 53 percent for Labbe). Seventy-one percent of the right-handers had significant Labbe drainage of the left hemisphere versus 61 percent for Trolard. Sylvian drainage was not significant in either hemisphere. Data on left-handers was insufficient to draw conclusions (table 5 ) . There was no relationship between right and left hemisphere superficial venous drainage and sylvian point angle differences in both right-handers and left-handers.
Table 4. Major transverse sinus flow correlated with (right-side versus left-side) sylvian point angle (R:L SPA) difference in right-handers and left-handers
Table 5. Major right and left hemispheric draining veins in right-handers and left-handers
NEUROLOGY March 1975 221
Arteriographic correlates of handedness
Discussion. Despite the extensive literature dealing with hemispheric functional differences, little has been written about morphologic hemispheric differences. Physical anthropologists have indirectly appreciated such differences by noting asymmetries in the cranial vault. Inglessis ( 1 9253), Kavue ( I 93 14), and Gundara and Zivanovic ( 1968*) noted that the impression on the vault caused by the occipital lobes was two to four times more often deeper on the left than on the right. This indicated a greater length of the left hemisphere than of the right. Smith (19076) pointed out that the "area striata" (posterior parietal-occipital cortex) was significantly greater on the left side in 10 brains studied. I n g l e s ~ i sin , ~a large series of brains obtained from a mental institution, noted that in 63.5 percent the left cerebral hemisphere weighed more than' the right and that in 66.8 percent the left lateral ventricle had a greater capacity. McRae, Branch, and Milner (1968') reported finding statistically significant hemispheral differences in the occipital horns of the lateral ventricles. In right-handed individuals with asymmetrical occipital horns, the left occipital horn was five times more often larger than the right. In left-handed persons showing asymmetry in the occipital horns, there was an equal chance of the right or left occipital horn being longer. The present study confirms the earlier report of predictable hemispheral differences in the middle cerebral arteries as they leave the Sylvian fissures. In 67 percent of right-handed individuals in the present study, the angle formed by the vessels leaving the posterior end of the Sylvian fissure was greater on the right than on the left by over 10 degrees. The mean difference between right and left sylvian point angles was 23.5 degrees. In only 21.4 percent of left-handed persons, on the other hand, was the right sylvian point angle larger than left by over 10 degrees. The mean difference between the right and left sylvian point angles was 6.6 degrees. The differences in the branches of the right and left middle cerebral arteries leaving the distal end of the Sylvian fissures reflect the anatomic differences in the right and left Sylvian fissures. These differences were noted by Cunningham (18928), who showed that the posterior end of the right Sylvian fissure was commonly higher than the left, reflecting the fact that the right parietal operculum is commonly smaller than the left. In addition, Geschwind and Levitsky (196g9) found that the planum temporale was larger on the left than on the right in 65 of 100 brains, and larger on the right in only 1 1 brains. These hemispheral differences in the Sylvian fissures are present in fetal life (Cunningham, 1892R; LeMay and Culebras, 1972l). Just as the greater bulk of the left parietal operculum appears to be reflected by the smaller left sylvian point angle, the distal superior sagittal sinus appears to be influenced by the relative bulk of the right and left occipital poles. This occipital pole asymmetry was first noted by Smith6 and was extended by Inglessis,3 who showed that the superior longitudinal sinus bends to the right in 60 percent of brains. Streeter (1 9 15l o ) has reported this preferential position in a 20 mm embryo. In our study, the most common position of the 222
NEUROLOGY March 1975
end of the sagittal sinus was to the right of the midline. In addition, the transverse sinus was higher on the right in 54 percent of right-handed patients versus only 3 1 percent of left-handed patients. This reflects the greater bulk of the posterior portion of the left hemisphere in right-handed patients. A relationship appears to exist between sylvian point angulation and the position of the posterior e'nd of the superior longitudinal sinus. The posterior end of the superior longitudinal sinus tended to be in the midline or to the left of the midline in patients with nearly equal sylvian point angles than in patients with right sylvian point angle larger than left sylvian point angle. The superficial veins of the brain have been the subject of several studies (Wold, 196311; DiChiro, 196212; Matsubara, 19611 3 ; Gvozdanovic, 195614). Changes in flow pattern in these vessels are common in pathologic situations."~13~14 Since most of the studies are in patients with disease, it is difficult to be certain of the venous flow in normal brains. We found, as have others,13 that the drainage on the two sides of the brain tends to be similar. DiChiroI2 correlated the superficial draining veins with cerebral dominance. In 53 percent of his patients with left hemispheral dominance by Wada test, the dominant draining of the left hemisphere was the vein of Labbe, while in 66 percent of patients with right cerebral dominance Labbe was the dominant vein of the right. In our study 32.7 percent of the right-handed patients had Labbe as the prominent draining vein of the left hemisphere and 15 percent had Labbe as the prominent vein of the right hemisphere. The number of left-handed patients in our study in whom superficial venous drainage could be determined was too small to be of significance. REFERENCES 1. LeMay M, Culebras A: Human brain - morphologic differences in the hemispheresdemonstrableby carotid arteriography.N Engl J Med 287:168-170, 1972 2. Taveras JM, Wood EH: Diagnostic Neuroradiology. Baltimore, The Williams & Wilkins Company, 1964 3. lnglessis M: Uber Katazitasul-evscheideder linken und rechten Halfte am Schadel bei Menschen uber Hirn asymmetrian. ZGes Neurol Psych 97:354-373, 1925 4. Kavue I: Normale assymetrie des menschildchen Schadels. Phil dissertation, Berlin-Leipzig, quoted in Gundara5, 1968 5. Gundara N, Zivanovic S: Asymmetry in East African skulls. Am J Phys Anthropology 28:331-338, 1968 6. Smith GE: On the asymmetry of the caudal poles of the cerebral hemispheres and its influence on the occipital bone. Anat Anz 30:574-578, 1907 7. McRae DL, Branch CL, Milner B: The occipital horns and cerebral dominance. Neurology (Minneap) 18:95-98, 1968 8. Cunningham DJ: Contribution to the Surface Anatomy of the Cerebral Hemispheres. Dublin, Royal Irish Academy, 1892 9. Geschwind N. Levitsky W: Human brain: Left-right asymmetries in temporal speech region. Science 161:I 86-187, 1968 10. Streeter GL: Venous sinuses of the dura mater. Am J Anatomy 181145-178,1915 11. Wold BS, Huang YP, Newman CM: The superficial sylvian venous drainage system. Am J RoentgenolRadium Ther Nucl Med 49:398-410, 1963 12. DiChiro G: Angiographic patterns of cerebral convexity veins and superficial dural sinuses. Am J Roentgenol Radium Ther Nucl Med 87:308-321, 1962 13. Matusubara T: An observation on cerebral phlebograms with special reference to the changes in superficial veins. Nagoya J Med Sci 23186-94,1961 14. Gvozdanovic V: Changes in the superficial veins in cases of intracranial expanding processes. Acta Radio146:195-202, 1956
Arteriographic correlates of handedness FRED H. HOCHBERG and MARJORIE LE MAY Neurology 1975;25;118 DOI 10.1212/WNL.25.3.118 This information is current as of March 1, 1975 Updated Information & Services
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Neurology ® is the official journal of the American Academy of Neurology. Published continuously since 1951, it is now a weekly with 48 issues per year. Copyright © 1975 by the American Academy of Neurology. All rights reserved. Print ISSN: 0028-3878. Online ISSN: 1526-632X.
