[Venous Anatomy of the Superior and Inferior Sagittal Sinuses].

The superior sagittal sinus(SSS)is contained within the dura, which consists of the dura propria and osteal dura at the junction of the falx cerebri, in addition to the attachment of the falx to the cranial vault. The SSS extends anteriorly from the foramen cecum and posteriorly to the torcular Herophili. The superior cerebral veins flow into the SSS, coursing under the lateral venous lacunae via bridging veins. Most of the bridging veins reach the dura and empty directly into the SSS. However, some are attached to the dural or existed in it for some distance before their sinus entrance. The venous structures of the junctional zone between the bridging vein and the SSS existed in the dura are referred to as dural venous channels. The SSS communicates with the lateral venous lacunae connecting the meningeal and diploic veins, as well as the emissary veins. These anatomical variations of the SSS are defined by the embryological processes of fusion and withdrawal of the sagittal plexus and marginal sinus.

Cortical and bridging veins of the upper cerebral convexity: a magnetic resonance imaging study.

PURPOSE: There is no study exploring the cortical veins (CVs) and connecting bridging veins (BVs) with neuroimaging modalities. The present study aimed to characterize these veins of the upper cerebral convexity. METHODS: A total of 89 patients with intact cerebral hemispheres and covering meninges underwent thin-sliced, contrast magnetic resonance imaging (MRI). In addition, three injected specimens were dissected in this study. RESULTS: In cadaver dissection, the BVs were observed to course in the arachnoid sheaths, suspended from the dura mater. The medial parts of the BVs, located near the superior sagittal sinus (SSS)-BV junction site, were occasionally exposed subdurally. The CVs were formed by venous channels arising from the cerebral gyri and those emerging from the sulci. On MRI, the CVs and connecting BVs were identified in the medial and latera convexity areas and medial surface of the cerebrum. These veins were highly variable in number, thickness, length, course, and distribution. In the medial convexity area, the CVs arising from the gyri were identified in 58% of patients, while they were found only in 11% of patients in the lateral convexity area. CONCLUSION: In the medial convexity area, involving the parasagittal region, the CVs connect more densely with the BVs that may predispose to injury during neurosurgical procedures. Mechanical impact exerted the area, diameter of the veins in the craniocaudal direction, and number of venous afferences may affect the SSS-BV junctional region in an indirect manner and lead to the development of acute subdural hematoma.

Microsurgical anatomy of the superior sagittal sinus and draining veins.

BACKGROUND: The superior sagittal sinus and the draining cerebral veins are often encountered during the surgery for parasagittal and falx meningiomas and during the interhemisperic transcallosal approaches. A knowledge about the variations from the normally described anatomy helps in anticipating and avoiding problems related to these structures during surgery. AIM: The normal variations in the disposition of the superior sagittal sinus and the number and direction of the draining veins in the Indian population have been studied. SETTINGS AND DESIGN: This is an anatomical study in the fresh cadavers. MATERIALS AND METHODS: Sixty fresh cadavers were examined in the autopsy theatre of the Forensic Medicine Department of the Hospital between March 2011 and February 2013. STATISTICAL ANALYSIS USED: Epi-Info, MS-Excel, and the Statistical Package for the Social Sciences (SPSS) were used for data analysis. RESULTS: The position of the superior sagittal sinus was variable and was up to within 1cm on either side of the sagittal suture. The origin of the superior sagittal sinus varied from the level of foramen caecum to a little posterior from the foramen caecum. The total length of the superior sagittal sagitttal sinus varied from 321 mm to 357 mm (average length 338.77mm); vertical compartments of the sinus were found in three-fourth of the cases studied. Tributaries were found in the herringbone pattern and varied from 13 to 19 on the right and 14 to 19 on the left. The Rolandic vein was the largest draining vein in most of the cases. The superior sagittal sinus drained predominantly to the right transverse sinus in three-fourth of the cases studied. The position of the torcula was variable; often towards the right side and at a higher level. The central sulcus was 49.93 mm posterior to the coronal suture and 130.78 mm anterior to the lambdoid suture. CONCLUSIONS: This is the first study of its kind in Indian population studying the anatomical variations in the anatomy of the superior sagittal sinus that may have a significant bearing on the neurosurgical approaches adopted.

A possible venous connection between the cranial and nasal cavity.

PURPOSE: The foramen cecum (FC) is a fine bony canal with the aperture located immediately anterior to the crista galli (CG). The venous structures in the regions of the FC and CG have been inconsistently described and are not well understood. Here we explore these veins using magnetic resonance imaging. MATERIALS AND METHODS: We enrolled 101 patients who underwent contrast examinations and exhibited intact skin, skull, dura mater, and intracranial dural sinuses. Imaging data were obtained as thin-sliced, seamless sagittal sections and were transferred to a workstation for analysis. RESULTS: In 84 % of the patients, tubular-shaped venous extensions arose from the rostral end of the falx cerebri and were confirmed to lie in the FC. These extensions were supplied by the superior sagittal sinus or the frontal cortical vein, and were classified into four types: rudimental slight projections, short and straight extensions, long and straight channels, and long and tortuous channels. Furthermore, 27.7 % of the patients exhibited a distinct venous channel between the venous extension in the FC and the median vestibular submucosa of the nasal cavity. Among these channels, 81.5 % were connected to the vein lying in the FC via a short channel that vertically pierced the CG. CONCLUSIONS: The FC contains tubular-shaped venous extensions that are supplied by the rostral end of the superior sagittal sinus or the frontal cortical vein. The cranial cavity, FC, and nasal cavity may be connected by a venous channel.

Determining the morphometry and variations of the confluens sinuum and related structures via a silicone painting technique on autopsy patients.

In this study, we aimed to investigate the morphometric and morphologic structures of the confluens sinuum (CS) and related structures with a silicone painting technique. We studied 30 cadavers. Twelve of them were washed with alcohol and filled with a silicone painting technique via the vena jugularis interna, internal carotid artery, and vertebral artery. The other 18 were autopsied postmortem. The CS and related structures were dissected under microscope. Their anatomy was investigated, and variations were noted. The diameters of the sinus sagittalis superior (SSS), CS, occipital sinus (OS), sinus rectus (SR), and bilateral transverse sinus (TS), and the angle between SSS and SR were measured. The mean diameters were 11.7 mm for SSS, 22.3 mm for CS, 5.25 mm for OS, 7.5 mm for SR, and 9.7 (right) and 9.1 mm (left) for TS. The angle between the SR and SSS was 58°. There was no difference in the bilateral venous structures that drained to the SSS and TS. There was an extra drainage to the CS from the left side in 4 cases. The right TS was located superiorly in 7 cases compared with the left TS, and this process was correlated with the type of CS. A septum in the SSS was detected in 2 cases. In addition, we encountered an OS in 80% of the cases. We conclude that the septum inside the CS affects the dominancy of the TS, the angle between the SSS and SR, and the other venous variations.

Venous lacunae presenting with unusual upward protrusion: an anatomic study using high-resolution magnetic resonance imaging.

PURPOSE: This study aims to investigate the distribution and anatomic features of venous lacuna presenting with unusual upward protrusion (VLUUP) using high-resolution magnetic resonance (MR) imaging. METHODS: This retrospective study included 59 consecutive outpatients who underwent MR imaging with gadolinium. Acquired imaging data were transferred to a workstation for analysis. RESULTS: The 30 male and 29 female subjects were aged from 10 to 76 years. A total of 46 VLUUPs located parasagittally were identified in 36 of the 59 patients, 24 on the right, and 22 on the left; 29 patients had one VLUUP, 4 patients had two, and 3 patients had three. Most VLUUPs (93 %) were distributed in the posterior third of the frontal region and the remainder (7 %) in the middle third. There were no VLUUP found in the anterior third of the frontal region or the parietal or occipital regions. The mean longitudinal and lateral dimensions of the VLUUPs and distance from the midline to the medial margin of the VLUUP were 9.7 mm (3.1-27.6), 6.9 mm (3.1-11.5), and 14.3 mm (1.6-43.5), respectively. CONCLUSIONS: The VLUUPs carry a higher risk of injury when making a bony window in or involving the parasagittal posterior frontal region. High-resolution MR imaging is useful for delineating the VLUUPs.

Investigation of the human bridging veins structure using optical microscopy.

In this paper, we investigated the brain-sinus junction and especially the bridging veins linking these two organs. Two types of optical microscopy were used: conventional optical microscopy and digital microscopy. We used thin histological sections prepared from a human brain, and stained with Masson's trichrome, hemalun and orcein. Finally we observed the path of the bridging vein inside the brain-skull interface. At smaller scales, wavy collagen fiber bundles were found and characterized inside the vein walls. Taking into account the orientations of the different sections with reference to frontal planes, we found that the bridging vein has a very complex geometry, which increases the difficulty to determine fiber orientations in its walls. Nevertheless, we found that collagen fiber bundles are mainly circumferentially oriented in the superior sagittal sinus walls. In this paper, we were able to characterize precisely the path of the bridging vein from the brain to the sinus, with different magnifications.

Could craniometric measurements explain the growth of the superior sagittal sinus?

OBJECTIVE: The objective of this study was to relate demographic variables and craniometric measures with measurements of the superior sagittal sinus (SSS) at different points along the path of the SSS. The findings were then discussed with regards to theories of skull growth. METHODS: We studied 33 skulls with known demographic characteristics and measured various craniometric parameters and distances related to the specific dimensions of the SSS. These data were statistically analyzed, and the results are presented. RESULTS: Of the 33 cadaver samples, 16 were female and 17 were male, aged between 28 and 87 years at the time of death. The cross-sectional area of the SSS measured at the coronary suture was positively correlated with the biauricular length. In addition, when measured 1.5 cm above the torcula, the cross-sectional area of the SSS was negatively correlated with the distance between the medial epicanthi. CONCLUSIONS: The relationships found may indicate that the growth of the SSS is proportional to the activity of each segment of the SSS that occurs along its path.

Sonographic evaluation of the superior sinus sagittalis.

OBJECTIVE: The aim of this study was to characterize the normal ultrasonographic growth of the fetal superior sinus sagittalis (SSS) throughout gestation. PATIENTS AND METHODS: In a prospective cross-sectional study, measurements of the fetal sinus sagittalis were obtained in patients undergoing elective fetal anatomical surveys or fetal growth scan at between 16.6 and 34.7 weeks of gestation. Special attention was given to the SSS of the fetal brain. On the coronal plane, the SSS may be easily identified immediately below the frontal bone, and anterior to the fetal head parenchyma. RESULTS: 206 fetuses were scanned. A regression line of the SSS was created throughout gestation and a first-degree correlation was found between gestational age (GA) and the SSS height (r = 0.418; p < 0.0001; SSS = -0.015 + 0.0178 × GA). Normal values were established for different gestational weeks. CONCLUSION: We provide ultrasonographic dimensions of the fetal SSS across pregnancy. This data potentially allows for prenatal diagnosis of abnormal appearance of the SSS.

The termination of superior sagittal sinus and drainage patterns of the lateral, occipital at confluens sinuum in newborns: clinical and embryological implications.

Drainage patterns of dural venous sinuses at confluens sinuum are variable and clinically significant. It has been generally investigated in adults; however, we thought that neonatal cadaver study might be more informative in views of embryological and clinical. A total of 33 skull bases of neonatal cadavers were resected to identify termination patterns of lateral sinus (LS), superior sagittal sinus (SSS) and occipital sinus (OS) at the confluens sinuum. Termination patterns of these sinuses were classified into six types: the SSS showed continuity with right transverse sinus (TS) (with OSs) (30.3%) (Type I); or multiple OSs (21.2%) (Type II). The SSS continued with left TS (with OSs) (12.1% (Type III); or with multiple OSs (6.1%) (Type IV). The SSS shows continuity with both TS (9.1%) (Type V). SSS symmetrically bifurcated, the confluens sinuum has a large OS (21.2%) (Type VI). Understanding of the cerebral venous drainage and large variation of the posterior fossa dural sinuses is crucially important for planning surgical intervention to some tumors in the neck which may require ligation of the internal jugular vein.

The diploic venous system: surgical anatomy and neurosurgical implications.

OBJECT: There are few systematic investigations of the dissected surgical anatomy of the diploic venous system (DVS) in the neuroanatomical literature. The authors describe the DVS relative to different common neurosurgical approaches. Knowledge of this system can help avoid potential sources of unacceptable bleeding and may impact healing of the cranium. METHODS: Using a high-speed drill with a 2-mm bit, the authors removed the outer layer of the compact bone in the skull to expose the DVS in 12 formalin-fixed cadaver heads. Pterional, supraorbital, and modified orbitozygomatic craniotomies were performed to delineate the relationship of the DVS. RESULTS: The draining point of the frontal diploic vein (FDV) was located near the supraorbital notch. The draining point of the anterior temporal diploic vein (ATDV) was located in all pterional areas; the draining point of the posterior temporal diploic vein (PTDV) was located in all asterional areas. The PTDV was the dominant diploic vessel in all sides. The FDV and ATDV could be damaged during supraorbital, modified orbitozygomatic, and pterional craniotomies. The anterior DVS connected with the sphenoparietal and superior sagittal sinus (SSS). The posterior DVS connected with the transverse and sigmoid sinuses and was the dominant diploic vessel in all 24 sides. Of all the major diploic vessels, the location and pattern of distribution of the FDV were the most constant. The parietal bone contained the most diploic vessels. No diploic veins were found in the area delimited by the temporal squama. CONCLUSIONS: The pterional, orbitozygomatic, and supraorbital approaches place the FDV and ATDV at risk. The major anterior diploic system connects the SSS with the sphenoparietal sinus. The posterior diploic system connects the SSS with the transverse and sigmoid sinuses.

Endoscopic and microscopic anatomy of the superior sagittal sinus and torcular herophili.

Surgery of the superior sagittal sinus (SSS) is a challenging areas for neurosurgeons. To better understand the anatomy of the SSS, we examined the chordae and arachnoid granulations in the lumen of the SSS and torcular herophili with the aid of an endoscope and a microscope, and re-evaluated the role of the chordae Willisii in preventing blood backflow. We prepared 10 SSS from fresh human cadavers during autopsies. After the cranial vaults were removed, an endoscope was inserted into the lumen of the sinus to examine the structures and morphological features of the chordae Willisii, and the topographic distribution of the arachnoid granulations. The sinuses were subsequently opened using standard anatomical methods and the intraluminal structures of the dural sinus were subjected to microanatomic analysis. In another five formalin-embalmed cadaver heads, blue latex was injected from the posterior end of the SSSs to observe filling of the SSS tributaries. We identified three types of chordae in the lumen of the SSS: valve-like chordae (48.3% of all chordae), followed by trabecular (31.5%) and laminar (20.2%) chordae. The laminar chordae at the posterior end of the SSS divide the sinus into two separate channels of different sizes. Similar structures were also seen in the lumen of the torcular herophili. The majority of arachnoid granulations were found as digitations in the lumen at the lateral wall or lateral recess of the middle segment of the SSS. Microscopic examination of the intraluminal structures of the SSS confirmed endoscopic findings. In the injection test we found that the SSS tributaries could be filled retrogradely with artificial dye, suggesting that the function of valve-like chordae in preventing the backflow of blood is restricted only to physiological conditions. Thus, we could visualize and examine endoscopically the intact intraluminal structures of the SSS, which may have therapeutic or diagnostic significance.

Feasibility and accuracy of a voxel-based neuronavigation system with 3D image rendering in preoperative planning and as a learning tool for young neurosurgeons, exemplified by the anatomical localization of the superior sagittal sinus.

It is essential for a neurosurgeon to know individual anatomy and the corresponding anatomical landmarks before starting a surgery. Continuous training, especially of young neurosurgeons, is crucial for understanding complex neuroanatomy. In this study, we used a neuronavigation system with 3D volumetric image rendering to determine the anatomical relationship between the sagittal suture and the superior sagittal sinus (SSS) in patients with intracranial lesions. Furthermore, we discussed the applicability of such system in preoperative planning, residency training, and research. The study included 30 adult patients (18 female/12 male) who underwent a cranial computed tomography (CT) scan combined with venous angiography, for preoperative planning. The position of the sagittal suture in relation to the SSS was assessed in 3D CT images using an image guidance system (IGS) with 3D volumetric image rendering. Measurements were performed along the course of the sagittal sinus at the bregma, lambda, and in the middle between these two points. The SSS deviated to the right side of the sagittal suture in 50% of cases at the bregma, and in 46.7% at the midpoint and lambda. The SSS was displaced to the left of the sagittal suture in 10% of cases at the bregma and lambda and in 13% at the midpoint. IGSs with 3D volumetric image rendering enable simultaneous visualization of bony surfaces, soft tissue and vascular structures and interactive modulation of tissue transparency. They can be used in preoperative planning and intraoperative guidance to validate external landmarks and to determine anatomical relationships. In addition, 3D IGSs can be utilized for training of surgical residents and for research in anatomy.

Morphological study of sinus flow in the confluence of sinuses.

The confluence of sinuses (CS; torcular herophili) is represented by the junction of the superior sagittal (SSS), straight (SS), occipital (OS), and two transverse sinuses (TS). The objective of this study was to interpret sinus flow around the CS by morphological investigation of the sinuses. This study is based on visual examination of dural venous sinuses in the region of the CS in 31 adult cadavers. In the inflow zone, we examined the direction of SSS and SS flow. In the communication zone, we examined the extent to which outflow sinuses communicate with other sinuses. In the outflow zone, we used the diameters of outflow sinuses to determine anatomical dominance. The SSS entered the CS via the right TS in 16 cases (51.6%) and via the center of the CS in 14 cases (45.2%). The SS entered via the center of the CS in 18 cases (58.1%) and via the left TS in 11 cases (35.5%). Outflow sinuses communicated freely in 26 cases (83.8%) and communicated partially in five cases (16.2%). Partial communication was the result of a septate CS. In terms of outflow, the right TS was dominant in 11 cases (35.5%), and in 18 cases (58.1%), outflow was symmetrical. The direction of SSS inflow was different from that of SS inflow, and partial communication was observed in five cases (16.1%). Therefore, the presence of a septum may be considered an anatomical factor, with implications in diagnosis or in the sacrifice of the outflow sinus of the CS.

Extracranial outflow of particles solved in cerebrospinal fluid: Fluorescein injection study.

Cerebrospinal fluid is thought to be mainly absorbed into arachnoid granules in the subarachnoid space and drained into the sagittal sinus. However, some observations such as late outbreak of arachnoid granules in fetus brain and recent cerebrospinal fluid movements study by magnetic resonance images, conflict with this hypothesis. In this study, we investigated the movement of cerebrospinal fluid in fetuses. Several kinds of fluorescent probes with different molecular weights were injected into the lateral ventricle or subarachnoid space in mouse fetuses at a gestational age of 13 days. The movements of the probes were monitored by live imaging under fluorescent microscope. Following intraventricular injection, the probes dispersed into the 3rd ventricle and aqueduct immediately, but did not move into the 4th ventricle and spinal canal. After injection of low and high molecular weight conjugated probes, both probes dispersed into the brain but only the low molecular weight probe dispersed into the whole body. Following intra-subarachnoid injection, both probes diffused into the spinal canal gradually. Neither probe dispersed into the brain and body. The probe injected into the lateral ventricle moved into the spinal central canal by the fetus head compression, and returned into the aqueduct by its release. We conclude this study as follows: (i) The movement of metabolites in cerebrospinal fluid in the ventricles will be restricted by molecular weight; (ii) Cerebrospinal fluid in the ventricle and in the subarachnoid space move differently; and (iii) Cerebrospinal fluid may not appear to circulate. In the event of high intracranial pressure, the fluid may move into the spinal canal.

A hypothesis of cerebral venous system regulation based on a study of the junction between the cortical bridging veins and the superior sagittal sinus. Laboratory investigation.

OBJECT: The cerebral venous regulation involved in various physiological and pathological processes has received little attention. Here the authors describe the anatomy of the junction between the cortical vein and the superior sagittal sinus (SSS) and propose a new theory of cerebral venous regulation. METHODS: Ten adult human cadaveric heads (20 sides), including five specimens into which stained latex had been injected, were used for anatomical study. Formalin-fixed cadaver heads were dissected to demonstrate the cortical veins along the SSS. The characteristics of the cortical bridging veins and their openings into the SSS were established by anatomical, histological, immunohistochemical, and ultrastructural study of the junction. RESULTS: After their subarachnoid course, the cortical bridging veins penetrated the SSS at different points in the dura mater depending on their rostrocaudal position. The venous endothelium stretched beyond the sinus endothelium. The orientation of the collagen fibers changed at the level of the venous openings, with the luminal diameter becoming narrow and oval-shaped. The major finding was the organization of the smooth-muscle cells at the end of each cortical vein. At this site and particularly in the frontoparietal region, the vessel resembled a myoendothelial "sphincter." The authors hypothesize that this organization is involved in cerebral venous system regulation. CONCLUSIONS: The point of convergence between the cortical veins and the SSS is a key area. The authors also hypothesize that the myoendothelial junction acts as a smooth sphincter and that it plays a role in cerebral venous hemodynamics and pathological conditions.

An anatomic study of the occipital transtentorial keyhole approach.

OBJECTIVE: To provide an anatomic basis of the occipital transtentorial keyhole approach (OTKA), then explore its feasibility and surgical indication. METHODS: Eight cadaveric heads were prepared for this anatomic study. A longitudinal linear 4-cm skin incision that begun at the upper margin of the transverse sinus, 1.5 cm away from the superior sagittal sinus. This was designed for the OTKA. The keyhole craniotomy and conventional craniotomy were performed sequentially for observation and measurement. RESULTS: The interhemispheric corridor and the supratentorial corridor can be used in the OTKA. The surgical field extended superior to the splenium, inferior to the superior medullary velum, ipsilateral to the middle and posterior parts of the medial and inferior temporal lobe, contralateral to the pulvinar, and anterior to the massa intermedia in the third ventricle. The exposure area of the OTKA was 72.05 ± 6.26 mm(2) and 182.97 ± 14.65 mm(2) before and after the tentorial incision, respectively. The exposure area of the conventional craniotomy was 187.28 ± 20.16 mm(2), which had no significant difference to the OTKA. The working angles of the five target points were all smaller for the OTKA than for the conventional approach. The depth of the posterior third ventricle that could be observed was 14.70 ± 2.54 mm with the OTKA. CONCLUSIONS: Compared with the conventional approach, the OTKA is a more minimally invasive surgical procedure for treatment of the lesions in the pineal region and the middle and posterior parts of the medial and inferior temporal lobe. However, the working angles are relatively narrow.

Intracranial MR venography using low-field magnet: normal anatomy and variations in Nepalese population.

INTRODUCTION: Magnetic resonance (MR) venography is considered a reliable imaging modality for the evaluation of intracranial venous system. The purpose of this study was to evaluate the normal venous anatomy and its variations in Nepalese population using low field MR technique. METHODS: One hundred patients with normal MR imaging of brain underwent MR venographic study. MR venograms were performed in 0.35 T MR scanner using a contiguous 2D time-of-flight MR angiographic technique. RESULTS: The flow gaps in the transverse sinus were seen in 47% of population, of which 91% occurred in the non-dominant side. Right transverse sinus was dominant in 73% population. Flow gap was observed in bilateral transverse sinus in one case, while it was seen in the dominant right transverse sinus in 6.3% population. Inferior sagittal sinus was observed in 11% cases. Internal cerebral vein was seen in 60 cases. Occipital sinus was observed in 4% of the cases. The basal vein of Rosenthal was observed in 34% of the cases, whereas vein of Labbe seen in 8% cases. Unilateralflow gap in the sigmoid sinus was seen in 5 cases. CONCLUSIONS: MR angiography done at low field MR unit is a reliable tool in cerebral venous sinus assessment, particularly major dural sinuses. The flow gaps in transverse sinus are frequently encountered anatomic variation. Visualization of small veins like inferior sagittal sinus, basal vein of Rosenthal, vein of Labbe, internal cerebral vein was inferior in our study compared to other studies done in high field MR unit.

A primo vascular system underneath the superior sagittal sinus in the brain of a rabbit.

The primo vascular systems (PVS) observed in the central nervous system have been limited to the ones floating in the cerebrospinal fluid. In those experiments, it was difficult to obtain the same results because the PVS was not fixed in a given anatomical position. In the current work, we report a finding of a PVS in a well-defined location, namely, underneath the superior sagittal sinus in the sagittal fissure, so that repetition of the experiments is possible. This provides a cornerstone for PVS research because the lack of reproducible sample-taking hindered a deeper study of the PVS, such as RNA sequencing or RNA microarray. This obstacle can be overcome through the discovery in the current work. This PVS showed characteristics of the PVS observed in other organs. It showed the bundle structure of subvessels, the parallel distributions of F-actins, and the rod-shaped nuclei. Furthermore, it had a primo node in front of the confluence of sinuses above the pineal body. It had branches shooting off from the main primo vessel in the subarachnoid space toward the cerebral hemispheres. The results indicate that this PVS underneath superior sagittal sinus has proper features to function as a flowing channel.

Morphometric evaluation of parasagittal venous anatomy for intracranial approaches: a cadaveric study.

AIM: Obstruction of superior sagittal sinus (SSS) and collateral bridging veins is a well-known reason of postoperative brain edema and brain infarct, however, morphometric anatomic studies done in the light of surgical landmarks aren't sufficient in number. Object of this study is to describe venous structures related to SSS with silicon injected cadaveric models. MATERIAL AND METHODS: This study was on 6 silicon injected cadaveric heads at Anatomy Department. Duramater was removed and veins on parasagittal area were examined. SSS morphology, veins draining into SSS, their size, number and distance were evaluated. RESULTS: Mean vein number draining into SSS is 2.9±1.5 at anterior to coronal suture (CS), between CS and vertex is 3.2±0.8, between vertex and lambdoid suture (LS) is 2.3±0.9, between LS and confluens sinuum 0.3±0.5. There was no statically difference between right and left sides (p=0.140, p > 0.05). Diameter of veins was 2.4±1.0 mm at anterior to CS, 3.0±1.2 mm at between CS and vertex, 2.4±0.7 mm at between vertex and LS, and 2.2±0.5 mm at between LS and confluens sinuum. CONCLUSION: Knowing details of anatomic structures of SSS and venous structures draining into it may protect the patients from many surgical complications. SSS and related structures with surgical landmarks are valuable for neurosurgeons.