THE ANGIOARCHITECTURE OF HUMAN ANTERIOR AND POSTERIOR CENTRAL GYRI / 解剖学报

The angioarchitecture of both anterior and posterior central gyri of thirty human brains was studied by means of scanning electron microscopy, double injection method and alkaline phosphatase method. The study was divided into two parts. (a) Pial vessels: The branching pattern of pial arteries on the gyrus surface could be classified into 4 types. Type Ⅰ (bilateral branching type) accounted for 44.44% of the total, type Ⅱ (unilateral branching) 17.99%, type Ⅲ (comb-like) 16.93% and type Ⅳ (irregular) 20.63%. Each gyrus was supplied by several main branches, forming various areas separated by poorly vascularized lines. Two types of anastomoses (general and straight anastomoses) were found. (b) Intracerebral vessels: based on the degree of their penetration, intracerebral arteries and veins were divided into 5 groups, respectively. They were short, intermediate and long cortical, subcortical and medullary vessels. Arteries gave off forward, horizontal and recurrent branches. There were more long cortical arteries in the anterior central gyrus and more intermediate arteries in the posterior. The arteries were not accompanied by veins. Though rich blood supply was found in layer Ⅲ-Ⅳ, there was a broad vascular network with large meshes in layer Ⅴ and Ⅵ in the anterior central gyrus. Problems in distinguishing arteries from veins and particular vascular features were discussed.

MICROANATOMY OF THE MESENCEPHALIC VEINS OF THE CHINESE / 解剖学报

A new method known as continuous arterio-venous perfusion and clearing of thick sections according to Mulligan's procedure Were applied. After the vessels of the mesencephalon were perfused, arteries revealed red colour and the -veins blafck. Under SXP-1 stereo-microscope, the morphology, rate of occurrence, tributaries and drainage of the interpeduncular veins, the posterior communicating vein, the lateral peduncular veins, the circumpeduncular veins, the veins of the pontomesencephalic sulcus, the lateral mesencephalic veins, the veins of the brachium conjunctivum, the precentral cerebellar vein and the quadrigeminal veins of 27 (54 sides) adult mesencephala were observed. The origin, course, drainage and outlet of internal veins such as antero-medial, anterolateral, lateral and posterior veins of 10 adult mesencephala were investigated and compared with 3 venograms of mesencephalon from other specimens. The clinical significance of some of the above vessels were discussed.

MICROANATOMY AND SEM OBSERVATIONS OF INTRACEREBRAL VESSELS / 解剖学报

Intracerebral vessels from 10 hemispheres of children were perfused with ABS and observed under the 6212-Ⅲ surgical microscope and TSM-Ⅰ scanning electron microscope.1. The arterial network of the pia mater shows irregular anastomoses. Many terminal branches in the meshwork do not form anastomosis but perforate into the brain tissue at right angle. Most of the points where the arteries perforate are longit udinally arranged along the gyri.2. The venous network of the pia mater usually lies deeper than the arteries and becomes superficial to the latter after joining together to form larger vessels.3. The cortical arteries have an average diameter of 44.3?m. They are densely distributed like hairs of a brush.4. The tributaries of the cortical veins join to form larger veins assuming the shape of an inverted fir tree.5. The medullary arteries are different in length and in diameter. The diameter averages 158.2?m. The arteries perforating through the top of the gyrus are straight but those from the sulcus bend to a certain degree after they pass through the cortex. Branches from the middle segments come out vertically and form "T"-shape branches. The deep segments send out branches like the roots of a tree and form widespread anastomoses with the central arteries. Wavy, tortuous medullary arteries can be also found. The casts of these arteries were observed under the SEM.The medullary veins and central arteries have been studied and described microanatomically.

THE DISTRIBUTION OF INTRACEREBRAL ARTERIES IN THE NEWBORN / 解剖学报

Intracortical distribution of arteries were studied on thick sections prepared from brains of 11 newborns after injection and fixation. The results are as follows.1. Branches from the cerebral arteries form a pial arterial network on the cortical surface. The larger pial arteries are supplied with vasa-vasorum and perivascular vessels. They send out cortical and medullary arteries penetrating the cortex vertically from the surface.2. The distribution of arteries in the entire cortical area can be represented by the pattern observed in a single gyrus, which serves as a general rule. The cortical arteries arising from the pial arteries penetrate into the cortex vertically and are arranged regularly which appear as a brush border that curves with the cerebral surface in sections. The diameter of the long cortical arteries is 16～31 ?m, while that of the short ones is 7.5～15.4 ?m. All these arteries send out branches at right angles which anastomose with one another to form a dense polygonal or irregular vascular network.The medullary arteries pass directly through the cortex into medulla. The diameter of the long medullary arteries is 48～61 ?m and that of the short ones, 35～47 ?m. Those entering from the top of each gyrus pass directly to the deep medulla, whereas those from the sulcus to the junction between the cortex and medulla exhibit various degrees of curvature. The medullary arteries send out branches at right angle, which, in turn, form T-shaped bifurcations, interconnecting each other in an oblong lattice framework.3. The central arteries penetrate the base of the brain, fan out and arch upward to reach the corpus striatum. Arteries may penetrate into the thalamus from posteriolateral, inferio-medial or superior surface. They branch with acute angles and form dense network with polygonal, triangular, circular and irregular interspaces. The arteries of the internal capsule also branch at right angles, show "T" bifurcations after a short distance and form an oblong vascular network.

AN OBSERVATION ON VENAE CEREBRI PROFUNDAE OF THE CHINESE / 解剖学报

For the study of venae cerebri profundae of the Chinese, 50 previously fixed adult cerebral hemispheres and 11 brains of the newborn were investigated. The adult cerebral hemispheres were dissected under the stereoscopic microscope. All the 11 brains of the newborn were treated within 24 hours after death. Six percent gelatin solution containing 6% vermilion was injected into arteria carotis interna while a mixture of Indian ink with 3% gelatin was injected into vena jugularis interna. The specimens were fixed, sectioned into slices of 1～3 mm thick, cleared and observed under stereoscopic microscope. The findings were summarized as follows:1. vena cerebri interna was mostly formed by the continuation of v. thalamostriata superior after it curved inward and backward. In 38.00%?6.86 of the cases it united with v. choroidea superior and v. septi pellucidi at the site of the curvature. In 32.00%?6.6 it didn't receive any veins. In 12.00%?4.60 it united with v. septi pellucidi and 80.00%?3.84 with v. choroidea superior, while other occurrences were rare.In 80.00%?5.66 of the cases, Vena cerebri interna took its course at the posterior margin of the interventricular foramen. The rest started at the anterior one third (12.00%?4.60)and middle one third (8.00%?3.84) of the thalamus respectively.The source, position and course of v. thalamostriata superior, v. choroidea superior, v. septi pellucidi and v. ventriculi lateralis medialis were observed and described.2. v. basalis was formed by the union of the v. cerebri anterior, v. cerebri media profunda and v. ventricularis lateralis inferior. 70% of v. cerebri anterior emptied into v. basalis whereas the other 30% into the adjacent venous sinuses. v. cerebri media profundae, most of which received vv. thalamostriata inferior, emptied into v. basalis in 68.00%?6.60 cases and the adjacent venous sinuses in 32.00%?6.60 v. ventricularis lateralis inferior emptied into v. basalis in 96.00%?2.77 cases and into v. cerebri magna in 2.00%?1.98, while in 2.00%?1.98 it was absent.3. The longitudinal anastomotic vein. was formed by the "T" shaped bifurcations of the small branches of v. thalamostriata superior, v. septi pellucidi and v. ventricularis lateralis medialis in the white matter within an area of 2 mm by the lateral angle of the lateral ventricle. It received numerous radially arranged small veins in the medulla of the cerebral hemisphere. The longer ones of these veins might extend to the cortex and anastomoses between them and superficial cortical veins were demonstrated.

MICROSURGICAL ANATOMY OF THE ARTERIES OF BRAIN STEM——THE ARTERIES OF MESENCEPHALON AND MEDULLA OBLONGATA / 解剖学报

The continuous artery-vein infusion method was used for the study of the origin, number, course, anastomosis, point of penetration and distribution of external arteries on 60 sides and internal arteries on 18 sides of the brain stem (mesencepha- lon and medulla oblongata) in Chinese under magnifiers (10-16?). The arteries of the brain stem can be divided into four groups: the anteromedial, anterolateral, lateral and posterior arteries. Each group originates from several different arteries. The spot where external arteries penetrate into the substance of brain stem is called the point of penetration, several points of penetration concentrating together make the dense penetrating area. The dense penetrating areas on mesencephalon are the interpeduncular fossa and sulcus lateralis and those on the medulla oblongata are the fissurae mediana anterior and sulcus posterior to olive. There are fine arterial networks in the pia mater of the brain stem. In the mesencephalon and the closed portion of the medulla oblongata, the internal arteries traverse centripetally while in the open portion of the medulla oblongata, they course towards the floor of the fourth ventricle. The calibre of arteries in each group decreases anteroposteriorly. A comparatively constant blood supply area is available to each group.

AN OBSERVATION OF THE ARTERIAL SYSTEM OF CHINESE BRAIN Ⅲ. THE CEREBELLAR ARTERIES / 解剖学报

The cerebellar arteries including the arterial supply to the dentate nucleus had been studied on 103 Chinese brians (80 adults, 23 children) by dissection, angiography, clearing method and dissection under stereoscopic microscope. The following results were obtained:1. The superior cerebellar artery which arose mostly from the upper end of the basilar artery near the posterior cerebral artery was one(82.52?2.68％)or two (17.48?2.68％) in number on each side. It was grouped into simple-trunk type (one trunk on each side 69.90?4.52％), double-trunks type(two trunks on each side 4. 86?2.13％), and mixed type (one trunk on one side and two on the other 25.24?4.28％).It passed backward around the cerebral peduncle and was more frequently divided into lateral and medial branches.2. Most of the anterior inferior cerebellar arteries sprang from lower third (66.49?3.29％) and middle third (12.14?2.69％) of the basilar artery. The rest (15.06?2.69％) sprang from posterior inferior cerebellar and vertebral arteries and upper segment of the basilar artery. It was absent in 6.31?1.69％.3. The posterior inferior cerebellar artery arose mostly from the vertebral artery (77.18?2.92％)and was absent in 6.80?1.95％. It formed a loop at its original segment and gave off 1～4 branches to medulla oblongata.4. The middle inferior cerebellar artery was present in 17.48?3.95％ and occurred on both sides in two cases.The course, position, distribution of all arteries mentioned above and their interrelationships were observed.5. The arteries to the dentate nucleus might be derived mainly from the superior cerebellar artery, but the anterior and posterior inferior cerebellar arteries also contributed some branches to it. These branches were found mostly 5～6 in number on the superior surface and 3～5 in number on the inferior surface.

ANGIOARCHITECTURE OF HUMAN VISUAL CORTEX / 解剖学报

In order to observe the pial and intracortical vessels in the upper and lower lips of calcarine sulcus, the normal human visual cortex of 15 brains (30 sides) were studied with scanning electron microscope (SEM), staining for alkaline phosphatase activity, continuous arterio-venous perfusion and clearing of thick sections according to Malligan's procedure. The results are: (1) Superficial pial arteries on visual cortex originate from calcarine artery, parieto-occipital artery, and inferior posterior temporal artery. Their branches destribute on the surface of the upper and lower lips of the calcarine sulcus resembling a comb. Two types of arterial anastomoses were found. The pial veins of the upper lip of the calcarine sulcus empty into the medial parieto-occipital vein, while those of the lower lip empty mostly into the medial occipital vein. (2) Intracortical arteries might be divided into five groups, i.e, short cortical artery, middle cortical artery, long cortical artery, subcortical artery and medullary artery. In general, they send out forward and recurrent branches. Veins might also be classified into five groups accordingly. There are four layers of vascular network within the striate cortex. The 3rd layer was clearly divided into sublayer 3a, 3b, 3c. The capillary density of the sublayer 3b is with lower density, which is just situated in Gennari's band. Angioarchitecture in the unstriate cortex is loosely arranged. The vascular density of each layer has been measured. The relationship between the blood supply of visual cortex and its clinical significance has been discussed as well.

AN OBSERVATION OF THE ARTERIAL SYSTEM OF THE CHINESE BRAIN Ⅳ. THE INTRACRANIAL PORTION OF THE VERTEBRAL ARTERIES AND THE BASILAR ARTERY / 解剖学报

The intracranial portion of the vertebral arteries and the basillar artery of 103 Chinese (80 adults and 23 children) brains have been studied. The diameter of the intracranial portion of the vertebral artery on the left side is usually greater than that on the right side. The anterior spinal artery comes off mostly from the vertebral artery. It descends, slants medially and unites with the opposite artery to form a single anterior spinal artery in front of the anterior median fissure of the medulla oblongata. The vertebral artery usually gives off 1～3 medullary branches, which enter the medulla oblongata mostly through the posteriolateral sulcus. The blood supply of medulla oblongata has been discussed.In 57.50?5.53% of the adults, the union of the right and left vertebral arteries to form the basilar artery was found at the level of pons, while in children, 47.83?10.39% was found at the level of the lower border of pons. The labyrinth arteries arise mostly from the anterior inferior cerebellar arteries (77.50?2.95), and in rare cases, from the superior cerebellar or vertebral arteries. The pontine branches coming off from each side of the basilar artery are usually 3～4 in number.