New buccinator myomucosal island flap: anatomic study and clinical application

The authors studied the vascular anatomy of the buccinator muscle by dissecting fresh cadavers. The anatomy of the buccal branches of the facial artery consistently confirmed the existence of a posterior buccal branch, a few inferior buccal branches, and anterior buccal branches to the posterior, inferior, and anterior portions of the buccinator. The buccal artery and posterior buccal branch anastomose to each other and ramify over the muscle. Several veins originate from the lateral aspect of the muscle, converge into the buccal venous plexus, and drain into the facial vein (from two to four tributaries) or into the pterygoid plexus and the internal maxillary vein (from the buccal vein). These vessels and nerves enter the posterior half of the buccinator posterolaterally. The facial artery and vein are located at variable distances from each other around the oral commissure and the nasal base. Two patterns of buccinator musculomucosal island flaps supplied by these buccal arterial branches are proposed in this article. The buccal musculomucosal neurovascular island flap (posteriorly based), supplied by the buccal artery, its posterior buccal branch, and the long buccal nerve, can be passed through a tunnel under the pterygomandibular ligament for closure of mucosal defects in the palate, pharyngeal sites, the alveolus, and the floor of the mouth. The buccal musculomucosal reversed-flow arterial island flap (superiorly based), supplied by the distal portion of the facial artery through the anterior buccal branches, can be used to close mucosal defects in the anterior hard palate, alveolus, maxillary antrum, nasal floor and septum, lip, and orbit. The authors have used the flaps in 12 patients. There has been no flap necrosis, and results have been satisfactory, both aesthetically and functionally.     

The vascularization of the human tela choroidea of the lateral ventricle

The human tela choroidea of the lateral ventricle is vascularized by arteries arising from the two systems which form the arterial circle of the base, i.e. the internal carotid system and the vertebral basilar system. This blood supply is given by one anterior choroidal artery and by several posterior choroidal arteries. These arteries anastomose to form multiple indirect and remote links between the carotid and vertebral basilar systems. The capillary networks of the tela choroidea of the lateral ventricle consists of a velar network and of a choroidal network. This duality is constantly observed in the choroid formations of the human brain. The venous vascularization of the tela is tributary of the venous circle of the base of the brain through choroidal veins that drain either into the internal cerebral veins or into the basal veins.     

Participation of the cava vein blood flow in forming the total venous return under influence of different modality stimuli on the circulation system

Participation of the anterior and posterior veins cava in forming the total venous return under pressor and depressor effects, stimulation of depressing foci of the medulla's ventral part, enhancement of pulmonary ventilation, hypoxia, hypothermia, administration of acetylcholine, histamine, corinfar, was shown to depend on the blood flow shift direction in each of the veins cava, dynamics of shifts' development in time, and intensity of the stimulus. In systemic responses, the blood flow shifts in the vena cava anterior much contribute to the total venous return at the maximum of the systemic arterial pressure rise (r = 0.87) whereas contribution of the vena cava posterior is the greatest during a later occurring increase in the venous return (r = 0.84). Along with increase in the stimulus intensity the vena cava anterior's part in forming the venous return becomes more limited whereas that of the vena cava posterior is enhanced.     

Intraosseous veins of the maxilla in the newborn]

The intraosseous veins of the maxilla in newborns grow larger with enlargement of the bone and become disposed in three mutually perpendicular planes. The venous plexus of the alveolar process is large. V. v. vallares are thin and interlace forming a network. The veins of interdental septum are well pronounced. The thick venous network of the periosteum and the mucous membrane of the nasal surface of the palatine process includes the vessels transversal and longitudinal to the nasal septum. The venous loops of the incisor part are of triangular, pentagonal and polygonal shape. The veins of the palatine process are connected with 3-4 large vessels falling into the vessels of the tear duct. The transversal and oblique veins of the oral surface of the palatine process are connected with large vessels disposed in parallel to the medial structure of the hard palate. The venous network of the incisor part of the bone is restricted by densified small arc-shaped plexuses. Two-three largest veins lie sagittally and, connected by arc-shaped anastomoses, are tributaries of the vessels of the palate bone, soft palate and pharynx.     

On the development of the venous system in Polyptems senegalus (Pisces)

In Polyptems senegalus a peculiar venous system exists. The pattern is symmetrical in embryos and in early-larval stages, but soon the asymmetrical development of the Cuvierian ducts, originating from vitelline veins, causes a predominance of the system to the right side. The two posterior cardinal veins coalesce except in the anterior region, where the right vein becomes the direct continuation of the single vein; in later stages the single posterior cardinal vein acquires a peculiar disposition, partially in the left and partially in the right kidney. The inferior jugular veins become asymmetrical as well. The anterior cardinal veins are replaced by lateral cephalic veins. A special vein in the abdomen may be considered as being a vena cava. Other peculiar items are the pulmonary veins. Other veins are more or less similar to those of other fishes.     

Valves of the small coronary veins in porcine hearts

The aim of the study was to investigate the existence of valves in small peripheral coronary veins of porcine hearts. The study was performed on 20 porcine hearts using standard histological methods. The veins in the subepicardial and intramyocardial regions of the anterior and posterior parts of the interventricular septum and in the wall of the right atrium were studied. Valves were present in intramyocardial veins (diameter of 75–180 μm), in the veins located just beneath the external surface of the myocardium (diameter 120–170 μm) and in the terminal segments of the ventricular veins (diameter 250 μm) opening into the stems of the anterior interventricular vein and middle cardiac vein. Valves were also recorded in most veins of the subepicardial space. The described rich presence of valves in the small coronary veins may contribute to a better comprehension of their hemodynamic properties. These findings may also help to improve the understanding of the efficacy of retrograde application of medications, a novel technique in cardiology and cardiac surgery.     

Veins of the human cerebellum

(1) The veins of the human cerebellum, which may be classified into internal and external venous channels, correspond, in this respect, to the veins of the cerebral hemispheres. (2) The external cerebellar veins are arranged in three groups which, in turn, correspond to the three cerebellar surfaces and which communicate extensively. Accordingly, the terminal segments of the cerebellar veins overlap, which implies that no one-to-one relationship exists between the mouths of the individual veins and their respective distributions. (3) The terminal segments of the cerebellar veins are the superior petrosal sinus, the tentorial venous sinuses, the great vein of Galen and the internal vertebral plexus. (4) The tentorial venous channels may form a collateral venous arrangement. (5) The internal cerebellar veins consist of the nuclear veins and the medullary veins. (6) The medullary veins form a cortex-perforating group and a group located in the basal medullary region. The latter form a venous arborization of blood vessels not described thus far. This group of veins opens chiefly into the vein of the lateral recess of the fourth ventricle.(7) Attention is called to a 'venous watershed' corresponding to the one that exists in the cerebral hemispheres. (8) The veins of the dentate nucleus are composed of several venous channels draining its external surface and one single vein draining its internal surface. The latter has not been described thus far. The external veins of the dentate nucleus open into the venous star and the cortex-perforating veins. The internal nuclear vein, on the other hand, emerging from the hilum of the dentate nucleus, runs along the superior cerebellar peduncle. Thus, the term 'vena centralis nuclei dentati' appears to be appropriate to designate this vessel. It ultimately opens into the precentral cerebellar vein. (9) In certain places, various-colored substances used for injection form mixed pools.     

New vascular system in reptiles: anatomy and postural hemodynamics of the vertebral venous plexus in snakes.

Using corrosion casting, we demonstrate and describe a new vascular system--the vertebral venous plexus--in eight snake species representing three families. The plexus consists of a network of spinal veins coursing within and around the vertebral column and was previously documented only in mammals. The spinal veins of snakes originate anteriorly from the posterior cerebral veins and form a lozenge-shaped plexus that extends to the tip of the tail. Numerous anastomoses connect the plexus with the caval and portal veins along the length of the vertebral column. We also reveal a posture-induced differential flow between the plexus and the jugular veins in two snake species with arboreal proclivities. When these snakes are horizontal, the jugulars are observed fluoroscopically to be the primary route for cephalic drainage and the plexus is inactive. However, head-up tilting induces partial jugular collapse and shunting of cephalic efflux into the plexus. This postural discrepancy is caused by structural differences in the two venous systems. The compliant jugular veins are incapable of sustaining the negative intraluminal pressures induced by upright posture. The plexus, however, with the structural support of the surrounding bone, remains patent and provides a low-pressure route for venous return. Interactions with the cerebrospinal fluid both allow and enhance the role of the plexus, driving perfusion and compensating for a posture-induced drop in arterial pressure. The vertebral venous plexus is thus an important and overlooked element in the maintenance of cerebral blood supply in climbing snakes and other upright animals.     

Localization of the sites of pulmonary vasomotion by use of arterial and venous occlusion

In this study, we present a new approach for using the pressure vs. time data obtained after various vascular occlusion maneuvers in pump-perfused lungs to gain insight into the longitudinal distribution of vascular resistance with respect to vascular compliance. Occlusion data were obtained from isolated dog lung lobes under normal control conditions, during hypoxia, and during histamine or serotonin infusion. The data used in the analysis include the slope of the arterial pressure curve and the zero time intercept of the extrapolated venous pressure curve after venous occlusion, the equilibrium pressure after simultaneous occlusion of both the arterial inflow and venous outflow, and the area bounded by equilibrium pressure and the arterial pressure curve after arterial occlusion. We analyzed these data by use of a compartmental model in which the vascular bed is represented by three parallel compliances separated by two series resistances, and each of the three compliances and the two resistances can be identified. To interpret the model parameters, we view the large arteries and veins as mainly compliance vessels and the small arteries and veins as mainly resistance vessels. The capillary bed is viewed as having a high compliance, and any capillary resistance is included in the two series resistances. With this view in mind, the results are consistent with the major response to serotonin infusion being constriction of large and small arteries (a decrease in arterial compliance and an increase in arterial resistance), the major response to histamine infusion being constriction of small and large veins (an increase in venous resistance and a decrease in venous compliance), and the major response to hypoxia being constriction of the small arteries (an increase in arterial resistance). The results suggest that this approach may have utility for evaluation of the sites of action of pulmonary vasomotor stimuli.     

The development of the septum primum relative to atrial septation in the mouse heart

The septum primum in the mouse originates as a thickened primordium with a straight rather than a sickle-shaped ventral border. It is covered on its ventral border by anterior cushion material which is continuous over the roof of the atrium with the principal anterior cushion mass. A process of cavitation thins the septum primum and precedes actual fenestration. This process shifts the membranous septum to the left thereby providing room for the septum secundum to overlap on the right side. The septum primum cannot contact the posterior cushion until closure of the sinus venosus gutter which is described. The closure of the interatrial foramen, later the foramen primum, is accomplished by cell growth of the anterior cushion material. The ventral thick border of the septum primum contributes to the ventral limbus and the caudal thickened boundary of the fossa ovalis with some contribution from the left venous valve. These boundaries as well as the membranous portion of the interatrial septum are derived from the same primordium, namely the septum primum.     

Blood supply of the rat hypothalamus. VI. Posterior region of the hypothalamus (nucleus hypothalamicus posterior, nuclei praemammillares, nucleus supramammilaris, mammilary body).

It was shown by the double ink-filling technique that the arteries of the rat premammillary region and mammillary body arise from the a. communicans posterior while these areas are drained by the anterior interpeduncular vein. Disregarding some minor overlaps and anastomoses, the blood supplies of the two territories are independent of each other and from the neighbouring areas of the hypothalamus, diencephalon and mesencephalon. Arteries of the premammillary region arise from the premammillary artery, except for some branches of the posterior tuberal and interpeduncular arteries. The mammillary body is supplied by three mammillary arteries (anterior, posterior and lateral). The premammillary region drains into the anterior and posterior premammillary veins. Venous blood of the mammillary body is collected by the anterior and posterior mammillary veins which end in the anterior interpeduncular vein. The circulation of individual premammillary and mammillary nuclei is described in detail.     

The intrarenal and pericapsular venous systems of kidneys of the ringed seal, Phoca hispida

The kidneys of Phoca hispida are comprised of many closely adherent renculi, each of which is a small kidney, functionally independent of its neighbours except with respect to venous drainage. Venous blood from the rencular parenchyma drains to the periphery through interlobular veins. These interlobular veins empty into a perirencular plexus comprised of subcapsular veins on the free surface of the renculus, interrencular veins on adjoined surfaces, and marginal subcapsular veins lying in the furrows between adjoined renculi. A pericapsular plexus of large veins overlies the marginal subcapsular veins and has frequent connections with them. Blood drains from the pericapsular plexus into large superficial collecting veins that converge over the surface of the kidney toward the divided hilum and connect directly to the paired trunks of the posterior vena cava. There are also connections to other major venous systems of the region. There is no arcuate venous system, no major vein at the rencular hilum, and no vein of consequence emerging from the renal hilum. Venous outflow is virtually entirely directed to the peripheral plexuses. The venous pattern differs from that of most mammals in which blood drains from the renal parenchyma to arcuate veins and leaves the kidney through a renal vein, or veins, emerging from the hilum. The walls of veins in the kidney are remarkably thin in comparison to their size. Subcapsular veins up to 0.5 mm wide have walls on the parenchymal side that in places consist only of a thin, fenestrated endothelium and a basal lamina.     

Extra-alveolar veins are contiguous with, and leak fluid into, periarterial cuffs in rabbit lungs.

We previously observed physiological evidence that arterial and venous extra-alveolar vessels shared a common interstitial space. The purpose of the present investigation was to determine the site of this continuity to improve our understanding of interstitial fluid movement in the lung. Orange G and Evans blue dyes were added to the arterial and venous reservoirs, respectively, of excised rabbit lungs as they were placed 20 cmH2O into zone 1 (pulmonary arterial and venous pressures = 5 cmH2O, alveolar pressure = 25 cmH2O). After 10 s or 4 h the lungs were fixed by immersion in liquid N2, freeze-dried, cut into 5-mm serial slices, and examined by light macroscopy. Serial sections of 0.25-0.5 mm were subsequently examined by scanning electron microscopy. In the animals subjected to the zone 1 stress for 4 h, arterial and venous extra-alveolar vessels were surrounded by cuffs of edema. The edema ratio (cuff area divided by vessel lumen area) was greater around arteries than veins and decreased with increasing vessel size. Periarterial cuffs usually contained orange dye and frequently contained both orange and blue dye. Lymphatics containing orange or blue dye were frequently seen in periarterial cuffs. Scanning electron microscopy demonstrated that extra-alveolar veins of approximately 100 microns diameter were anatomically contiguous with arterial extra-alveolar vessel cuffs. In rabbit lungs, both arterial and venous extra-alveolar vessels (and/or alveolar corner vessels) leak fluid into perivascular cuffs surrounding arterial extra-alveolar vessels, and lymphatics located in the periarterial cuff contain fluid that originates from both the arterial and venous extra-alveolar vessels.     

Vascular anatomy of the anterolateral thigh flap

Arterial and venous anatomy and their relation to the anterolateral thigh flap were examined in 10 specimens of six fresh cadavers in which radiopaque materials were injected into both the arterial and venous systems. Territories and positions of individual perforating arteries were measured, and the venous drainage pathway of the flap was analyzed. All specimens were radiographed stereoscopically to observe the three-dimensional structure of the arteries and veins. The territory of each perforating artery was smaller than expected. Most of the venous blood that had perfused the dermis was considered to pool in a polygonal venous network located in the skin layer and to enter the descending branch of the lateral circumflex femoral artery through large descending veins. The venous territories were considered different from the arterial territories. The findings in this study suggest that the design of the anterolateral thigh flap should be based on the venous architecture rather than on the arterial architecture and that the flap survival rate might be improved if thinning is performed appropriately.     

Status of the circulatory bed of the vascular membrane of the eyeball and retrobulbar structures during experimental venous stasis

In 43 test animals the state of the blood bed in the retrobulbar formations and the eyeball vasular tunic has been studied under venous congestion produced by ligation of the anterior vena cava (in dogs) and both external jugular veins (in rabbits). A complex of histological, histotopographic, morphometric and variation-statistical techniques has been used. The results obtained demonstrate that disturbances in the venous outflow in the anterior vena cava system produce certain responses in all parts of the retrotubular adipose tissue, of the eyeball muscles, of the optic nerve tunics, of the vascular tunic. Certain stageness is noted in the course of venous congestion. Places of the greatest morphological changes in the eyeball vascular tunic are determined. They are zones of vorticose veins formation and the area corresponding to the posterior pole of the eyeball. The analysis of the specific areas of the intermuscular arteries and veins cross sections demonstrates that in the reaction of these vessels to the different venous outflow in the anterior vena cava system these is certain unevenness in different ofthalmic muscles.     

Blood supply of the trachea and bronchi in the rat

Existence of longitudinal and circular arterio-arterial anastomoses are stated, as well as various ways of outflow from the veins of the organs studied; this demonstrates essential compensatory abilities of this bed in blood supply regulation and draining at inflow and outflow from the microcirculatory system bed. Different topography of the arterial sources, venous plexuses, capillary fields allows to suppose different histophysiology of the tracheal zones mentioned: the anterior (laryngotracheal), middle and posterior (bifurcational). For the tracheal microcirculatory bed, metamerically repeated microcirculatory areas are peculiar. Distribution of the bronchial arteries takes place up to the terminal bronchi. In the area of the latter, anastomoses of the bronchial vessels with the pulmonary artery are observed.     

Compliance and smooth muscle reactivity of rainbow trout (Oncorhynchus mykiss) vessels in vitro

Systemic veins have a profound influence on cardiac output in mammals. Venoregulatory mechanisms have not been adequately studied in fish and their existence has been questioned. In the present study, two characteristics of vascular mechanics, compliance and agonist-induced tension development, were investigated in rainbow trout vessels in vitro. Rapid compliance in the anterior cardinal vein and efferent branchial artery was calculated from step-wise changes in the volume-pressure curve of isolated vessel segments. Agonist-induced tension development was examined in four veins; anterior and posterior cardinals, intestinal and duct of Cuvier. Venous compliance was not altered in response to epinephrine, norepinephrine or angiotensin II, while efferent branchial artery compliance was decreased by 10^-6 mol·l^-1 epinephrine and norepinephrine but not angiotensin II. The ratios of venous to arterial compliance in vessels from two rainbow trout strains were similar (21:1 and 32:1) and consistent with the ratio reported for mammalian viens (24:1). Trout veins contracted in response to agonists in both an, agonist- and vesselspecific manner. The greatest tension per vessel wet weight was produced in anterior cardinal vein. The response pattern of anterior cardinal vein and duct of Cuvier were similar; acetylcholine, arginine vasotocin, epinephrine and norepinephrine, and the thromboxane A₂ agonist, U-44,069, produced approximately identical contractions, whereas angiotensin II was virtually ineffective. Conversely, angiotensin II was more potent than epinephrine in posterior cardinal vein. In cumulative dose-response experiments, epinephrine was equipotent in anterior cardinal vein and duct of Cuvier, whereas the latter was less sensitive to acetylcholine. Both atrial natriuretic peptide and sodium nitroprusside relaxed precontracted veins. This is the first study to determine compliance in fish vessels and the contractile nature of different rainbow trout veins. These findings suggest that venous tone and therefore cardiac output in fish may be regulated by neural or humoral mechanisms.Abbreviations ACH acetylcholine - ACV anterior cardinal vein - ANG II salmon asn¹-val⁵ angiotensin II - ANP rat atrial natriuretic peptide - AVT arginine vasotocin - DNR Department of Natural Resources - DOC duct of Cuvier - EBA efferent branchial artery - EC₅ threshold dose producing 5% maximal contraction - EC₅₀ dose producing 50% maximal contraction - EPI epinephrine - HI K⁺ 80 mmol·l^-1 - KCl IV, intestinal vein - NEPI norepinephrine - PBS phosphate buffered saline - PCV posterior cardinal vein - SNP sodium nitroprusside - U-44,069 thromboxane A₂ agonist     

Flow regulates arterial-venous differentiation in the chick embryo yolk sac

Formation of the yolk sac vascular system and its connection to the embryonic circulation is crucial for embryo survival in both mammals and birds. Most mice with mutations in genes involved in vascular development die because of a failure to establish this circulatory loop. Surprisingly, formation of yolk sac arteries and veins has not been well described in the recent literature. Using time-lapse video-microscopy, we have studied arterial-venous differentiation in the yolk sac of chick embryos. Immediately after the onset of perfusion, the yolk sac exhibits a posterior arterial and an anterior venous pole, which are connected to each other by cis-cis endothelial interactions. To form the paired and interlaced arterial-venous pattern characteristic of mature yolk sac vessels, small caliber vessels of the arterial domain are selectively disconnected from the growing arterial tree and subsequently reconnected to the venous system, implying that endothelial plasticity is needed to fashion normal growth of veins. Arterial-venous differentiation and patterning are controlled by hemodynamic forces, as shown by flow manipulation and in situ hybridization with arterial markers ephrinB2 and neuropilin 1, which show that expression of both mRNAs is not genetically determined but plastic and regulated by flow. In vivo application of ephrinB2 or EphB4 in the developing yolk sac failed to produce any morphological effects. By contrast, ephrinB2 and EphB4 application in the allantois of older embryos resulted in the rapid formation of arterial-venous shunts. In conclusion, we show that flow shapes the global patterning of the arterial tree and regulates the activation of the arterial markers ephrinB2 and neuropilin 1.