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The so-called fish vertebra deformity as manifest in sickle cell disease is shown to be different, both in contour and mode of development, from the familiar type of biconcave deformity commonly seen in the osteoporotic spine. The distinctive structural features which characterize this lesion are described. The deformity is unique in its local topography, its uniformity, and the manner in which it evolves.Evidence based on a consideration of the contour of the defect and its location within the bone indicates that it is produced, not by the destruction and compression of existing bone like the common types of fish vertebra deformity, but by the local inhibition of bone growth as the result of regional ischemia. The "end-plates" of the growing centra where cupping takes place are functionally analogous to metaphyses, and the regional vascular anatomy is such that only the central portion of the growth plate suffers ischemic damage when circulation is impaired through the branches of the nutrient artery. Th...

International audience; The nutrient arteries, located in the long bone diaphysis, are the major blood supply to long bones, especially during the early phases of growth and ossification. Their intersection with the central axis of the medullary area corresponds to the ossification center, and their opening on the outer bone surface to the nutrient foramen. Nutrient arteries/foramen have essentially been analyzed in humans, and only to a much lesser extent in a few mammals. Some studies have taken measurements of the nutrient foramen; others have investigated the shape and orientation of the nutrient canals, although only partially. No studies have analyzed the nutrient canal in three dimensions inside the bone and the relationships between nutrient foramen, nutrient canal, growth, and physiology require further investigation. The current study proposes to investigate in three dimensions the shape of the nutrient canal in stylopod bones of various mammals. Qualitative and quantitative parameters are defined to discuss the diversity in, for example, morphology, orientation, and diameter encountered, resorting to two different datasets to maximize differences within mammals and then analyze variation within morphologically and phylogenetically closer taxa. This study highlights a strong intraspecific variation for various parameters, with limited biological signal, but also shows trends. It notably provides evidence that canals are generally more numerous and relatively thinner in less elongated bones. Moreover, it shows that the growth center is located distally in the humerus and proximally in the femur, and that the canals are essentially oriented towards the faster growing end, so that the nutrient foramen does not indicate the location of the growth center. This result seems general in mammals but cannot be generalized outside of Mammalia. Further analyses of the features of nutrient arteries in reptiles are required to make comparisons with the trends observed in mammals.

Several laboratories, including our own, have investigated the physiology of bone blood flow by perfusion of the tibia via the nutrient artery. Any damage caused to the nerve supply by cannulation of the artery might affect the results. The possible effect of such damage was investigated by measuring blood flow to the dog tibia using a microsphere technique, before and after sympathectomy. No effect was found and the tibial nutrient artery is therefore a suitable vessel for perfusion when estimating nutrient exchange in bone.

SummaryStudies were made of the changes in blood flow in rabbits after localized depletion of femoral marrow or nutrient vessel ligation. Our findings confirm that the nutrient artery is the principal source of flow to medullary tissue in the diaphysis of long bones. They indicate further that (i) there is a highly effective collateral circulation to the medullary cavity, (ii) marrow regeneration is associated with an increased blood flow, and (iii) normal blood flow is restored at a time when the regenerated marrow after a localized depletion is indistinguishable from normal marrow.

The location of the nutrient foramen is important if a free vascularized fibular graft is to include endosteal as well as periosteal blood supply. More than 300 human fibulae were examined to determine the number, location, and size of the foramina in the shaft. Six percent of the bones had no apparent foramen. Ninety-six percent of the foramina were in the middle third of the fibula. In Caucasians this segment of the shaft should be used for free vascularized fibular transfers to increase the likelihood of including the endosteal blood supply.

• The principal nourishment to the rib in a free flap is derived from the nutrient artery that pierces the costal head and terminates in the medullary cavity. A question surrounds the adequacy of the periosteal vessels in providing nourishment to the entire bone. A study of the blood supply and bony metabolism in the osseous portion of four free flaps of rib and attached pleura used to reconstruct the laryngotrachea in four dogs was undertaken. A microvascular anastomosis was attached to the anterior intercostal artery. An intact anastomosis was demonstrated in all four animals with fill of the most distal arborization in the bone in three. Technetium Tc 99m scanning, tetracycline labeling, and light microscopy revealed healthy metabolizing bone. The airway in all four animals was widely patent. ( Arch Otolaryngol 1984;110:99-102)

The point of no return and the beginning of irreversible necrosis becomes evident somewhere between 5 and 30 minutes after the occlusion of a major nutrient artery to the human myocardium. Depending on the subsequent duration of complete obstruction and the time of reperfusion, the pre-existing load on the ventricle (mainly the product of afterload and heart rate) as well as the extent of available collaterals, the size of the infarction distal to the site of obstruction will vary from a minor lesion via major dyskinetic area to ‘sudden death’.

The morphology of the gills of a primitive air breather (Amia calva) was examined by light microscopy of semithin sections of gill filaments, and gill perfusion pathways were identified by scanning-electron microscopic analysis of corrosion replicas prepared by intravascular injection of methyl methacrylate. The arrangement of gill filaments and respiratory lamellae is similar to that ot teleosts with the exception of an interfilamental support bar that is fused to the outer margins of lamellae on adjacent filaments. The prebranchial vasculature is also similar to that of teleosts, whereas the postbranchial circulation of arches III and IV is modified to permit selective perfusion of the air bladder. Gill filaments contain three distinct vascular systems: (1) the respiratory circulation which receives the entire cardiac output and perfuses the secondary lamellae; (2) a nutrient system that arises from the postlammelar circulation and perfuses filamental tissues; (3) a network of unknown function consisting of subepithelial sinusoids surrounding afferent and efferent margins of the filament and traversing the filament beneath the interlamellar epithelium. Prelamellar arteriovenous anastomoses (AVAs) are rare, postlammelar AVAs are common especially at the base of the filament where they form a dense network of small tortuous vessels before coalescing into a large filamental nutrient artery. Unlike in most teleosts, the outer vascular margins of the lamellae are embedded in the interfilamental support bar and become the sole vasculature of this tissue. Arterial-arterial lamellar bypass vessels were not observed. Previously observed decreases in oxygen transfer across the gills during air breathing can be explained only by redistribution of blood flow between or within the respiratory lamellae.

We have studied the effect of various drugs on the intramedullary pressure in dog tibia after constant-flow autoperfusion of the nutrient artery by femoral arterial blood. The perfusion pressure and carotid arterial pressure were also recorded. Isoprenaline, acetylcholine, histamine, theophylline always lowered the perfusion pressure but had a variable effect on intramedullary pressure. This results from several factors e.g., perfusion pressure and intraosseous vasomotoricity. Adrenaline always caused a rise of the perfusion pressure and lowered the intramedullary pressure in most of the cases. Such effects were reduced or suppressed by alpha-blocking drugs. Isoprenaline caused a lowering of the perfusion pressure which was suppressed by propranolol. A rise of the intramedullary pressure through beta-induced vasodilatation was shown in some experiments. The effect of adrenaline on the perfusion pressure could be reversed after alpha-blockade. These results show the presence of intraosseous vascular alpha- and beta-adrenoceptors.

Experiments were performed to assess the responsiveness of vessels subserving bone tissue to nerve stimulation and to exogenously administered catecholamines and acetylcholine. Tibias of mongrel dogs were isolated and dissected free; the periosteum was left intact. The main nutrient artery was prepared and cannulated. Ring electrodes were placed around the artery. The preparation was perfused at constant flow with aerated (95% O2 - 5% CO2) Krebs-Ringer solution (37 degrees C) by means of a roller pump. The perfusion pressure was continuously recorded. For each preparation, the flow rate was used at which the response to a standard dose of norepinephrine was the largest. Periarterial electrical stimulation caused frequency-dependent increases in perfusion pressure; because these responses were blocked by phentolamine, they must be due to activation of sympathetic nerves. Injections of norepinephrine caused dose-dependent increases in perfusion pressure that were abolished by phentolamine. Acetylcholine caused dose-dependent, atropine-sensitive decrease of the constrictions caused by norepinephrine infusions. These experiments demonstrate that the isolated perfused tibia of the dog is a satisfactory preparation to investigate the direct effects of sympathetic nerve stimulation and naturally occurring vasoactive amines on bone blood vessels.

Tamai et al. [1] in 1970 first reported successful free transplantation of a large skeletal muscle in dogs using microneurovascular anastomoses. The rectus femoris muscle was transferred to isotopical and heterotopical recipient sites where the nutrient artery and vein and the motor nerve of the muscle were simultaneously coapted with the recipient vessels and motor nerve. A high rate of functional contraction could be obtained by the transferred muscle, and histological findings showed it to have an almost normal structure at five months postoperatively. The method suggested by this excellent laboratory work would seem to present the greatest potential for free transplantation of skeletal muscles which, since Volkmann’s documentation [2], had been believed impossible.

The extraosseus and intraosseous circulation to the first ray was evaluated by means of vascular injection techniques. The first metatarsal and metatarsophalangeal joint receive their blood supply from the first dorsal metatarsal artery, the first plantar metatarsal artery, and the superficial branch of the medial plantar artery. These three source arteries provide variable numbers of branches to the base, shaft, and head of the first metatarsal. Ramifications of branches to the head form an extensive capsular network that is more consistent and abundant on the dorsal and lateral aspects of the joint.The source of intraosseous vascularity consists of a diffuse network of fine periosteal arteries enveloping the diaphysis of the metatarsal, a single nutrient artery that perforates the first metatarsal at the lateral aspect of the shaft distally, and a system of metaphyseal and capital arteries that appear to constitute a major source of blood supply to the metatarsal head.

The distribution of blood flow to segments of the leg bones of anaesthetised dogs was studied using radioactive microspheres injected into the heart or the tibial nutrient artery. Following central injection, repeated measurements after an interval showed no change of pattern of distribution. The effects of ligation of the tibial nutrient artery during this interval suggested that 30% of the blood flow to the tibia is normally via this vessel, which predominantly supplies the diaphysis. This deduction differed from that derived from the injection of microspheres during perfusion through a tibial nutrient artery cannula, when half the flow reached the epiphyses. This proportion decreased and the flow to the diaphyseal marrow increased after alternate periods of perfusion and ischaemia, demonstrating the labile nature of bone blood flow distribution.

1 The nutrient artery to the tibia of anaesthetized dogs was perfused at a constant rate by blood from the femoral artery and the perfusion pressure in the artery, the intramedullary pressure of the bone and the pressure in the nutrient vein recorded. 2 Low frequency stimulation (1 to 5 HZ) of the lumbar sympathetic chain always increased the perfusion pressure but the intramedullary pressure sometimes increased, sometimes decreased and sometimes remained unchanged. 3 The alpha-adrenoceptor blocking agents, phentolamine (1 mg/kg i.v.) and dihydroergotamine (0.5 mg/kg i.v.) reduced or abolished these effects whereas the beta-adrenoceptor blocking agent, propranolol (1 mg/kg i.v.) did not modify them. 4 The nutrient vein end pressure did not differ significantly from the intramedullary pressure and underwent similar variations during stimulation of the lumbar sympathetic chain.

A patient with a 29-year history of denture wearing had her mandible augmented with a vascularized rib graft. The rib was contoured to fit the arch of the mandible and vascularized by means of the facial arteries to the intercostal vessels. The nutrient artery was not included in the vascularized bone graft. Cortical cancellous bone chips were packed around the rib to augment the buccal surface of the rib graft. Periosteal perfusion and vascularity of the transferred rib were well documented at 1 week, 1 month, and 6 months postoperatively by radionuclide scintigraphy. It is now 24 months after surgery and the patient began wearing a denture 2 months after the rib transfer. She underwent a split-thickness skin graft vestibuloplasty and floor-of-the-mouth lowering 12 months following the rib transfer with improvement in her denture-wearing capabilities, which has remained constant for 10 months. Vertical resorption of the graft at 3 months was 10 percent, at 6 months 15 percent, and it has stabilized at 25 percent.

Microsurgery opened a completely new field in bone transplantation with the free vascularized bone transfer. Oestrup and Fredrickson (1974) stressed that successful transplantation of bone is dependent on both the endosteal blood supply, i.e., the nutrient blood supply, and the periosteal blood supply. Using microsurgical techniques both blood supplies can be reestablished by anastomosing the donor vessels, artery and vein, to the recipient vessels (Berggren et al. 1982). After restoration of the blood supply the bony segment should be as well vascularized as a living bone, and therefore incorporation of the bone graft should be similar to fracture healing. Non-vascularized bone grafts will undergo complete remodeling until the periosteal and endosteal blood supply is reestablished. However, it is questionable whether, for example in free iliac crest grafts, the endosteal blood supply remains as effective as it was in the original site, since the medulla is no longer supplied by the original nutrient artery and vein.

Abnormalities of cardiac rhythm have been reported by others in patients with a persistent left superior vena cava. We present the histological findings from postmortem examination of the cardiac conduction system of two such patients. The first patient was a schoolboy who died suddenly and unexpectedly. His sinus node was abnormally small, his A-V node contained numerous venous lacunae and was stretched out beneath the enlarged coronary sinus, both A-V node and His bundle were dispersed in the central fibrous body in a fetal pattern, and isolated fragments of A-V nodal tissue were connected to the myocardium at the crest of the interventricular septum. The second patient complained of palpitations many months prior to surgical correction of an interventricular septal defect; his postoperative course included multiple arrhythmias and he died suddenly on the 16th postoperative day. Although his sinus node was histologically normal, the nutrient artery contained a polypoid fibromuscular mass virtually occluding its lumen; his A-V node and His bundle were also dispersed in the central fibrous body in the fetal pattern, and the A-V node contained numerous venous lacunae as well as being histologically disorganized in its cytological pattern. These anatomical findings may indicate a basis for various forms of cardiac electrical instability, and deserve consideration in the future evaluation of any patient found to have a persistent left superior vene cava, but particularly if there is clinical evidence suggesting an arrhythmia or conduction disturbance.

The arterial blood supply to the head, neck and tubercle of the caudal ribs in the adult dog was studied by means of microangiography. While the tubercle and the neck are supplied solely by medullary branches of the main nutrient artery, the rib head receives an additional supply via two groups of epiphyseal arteries. This vascular pattern is discussed with special reference to the free microvascular transfer of composite posterior rib grafts.

An efficient method to evaluate the patency of microvascular anastomoses and to predict flap viability is crucial when free flaps are used in reconstructive surgery. We report a study of 60 neurovascular island flaps in rats where the nutrient artery and/or vein were transected and anastomosed. Fluorescein dye was injected immediately after anastomosis, and the uptake and elimination of dye were quantified at 5-minute intervals with the fiberoptic perfusion fluorometer. Analysis of dye delivery clearly identified six hypofluorescent flaps presumed to be ischemic. In five of these flaps, revision was attempted. Three evidenced improved fluorescein uptake and elimination on reinjection of dye. These flaps survived, whereas the other two necrosed. Of the 54 flaps deemed patent after the first injection, two evidenced poor fluorescence on reinjection 3 hours later. These flaps necrosed and evidenced venous thrombosis (which probably occurred during the 3 hours between the first and second injections). Fiberoptic fluorometry can be employed to assess a free flap immediately after vascular anastomosis and throughout the critical hours postoperatively. Assessment of uptake and elimination after single or serial injections reflects flap perfusion and predicts viability with a high degree of accuracy.

The effect of regional hypercalcemia on histamine-induced gastric acid secretion from chambered fundic segments was studied in five anesthetized mongrel dogs. This preparation allowed direct infusion of calcium into the nutrient artery of the gastric segment whereby venous effluent calcium levels were maintained in excess of 14 mg%, while systemic calcium levels were within a normal range. Blood flow, as measured by a venous effluent technique, did not change. Acid secretion decreased from 43.03 ± 7.13 to 12.20 ± 5.72 μEq/min during calcium infusion and rose to 37.04 ± 3.83 μEq/min when the infusion was terminated. These results provide clear evidence that calcium has a direct and reversible inhibitory effect on histamine-induced parietal cell secretion from exteriorized fundic segments of dog stomach.

A technique is described using the rabbit as the 'animal model' to measure the rate of extraction of the bone-seeking agent, technetium labelled ethane-1-hydroxy-1, 1-diphosphonate (99Tcm-EHDP) following constant-rate infusion into the femoral nutrient artery. The extraction is shown to be approximately linear for a period of 60 min. Washout of the tracer from bone was followed for a further 60 min period and graphical analysis shows that each curve could be resolved into two distinct exponential functions. The 2-h residue of 99Tcm-EHDP in bone has been examined and is found to be dependent upon its route of administration. A high residue (43.7 +/- 5.1%) results when the infusate is delivered directly into the nutrient artery and the single muscular branch is tied off. Retrograde infusion via the femoral artery results in a lower residue (7.8 +/- 2.3%). The close correlation of these results in the rabbit with our previous findings in the dog suggested that the rabbit model described can be used to study the kinetics of other radiopharmaceuticals during their passage through bone.

The extraction of ceftazidime has been measured in bone by means of the outflow dilution technique following injection into the perfused nutrient artery of the canine tibia. The instantaneous extraction was found to be 0.71 +/- 0.18 and the net extraction was 0.55 +/- 0.25 (mean +/- S.D. n = 5). The extraction of this antibiotic is relatively high and this experiment demonstrates the fact that antibiotics leave capillaries in bone and pass into the fluid spaces where they can act on pathogenic organisms.

The microarchitecture of the rat metaphyseal nutrient artery, the major blood supply to the calcifying epiphyseal growth plate, was studied by light microscopic serial sections, model reconstruction of serial sections, and scanning electron microscopy of plastic corrosion castings. These techniques illustrate how the metaphyseal artery undergoes extensive arborization and anastomosis upon route through the metaphysis. From this vascular network, closed capillary sprouts abut hypertrophic chondrocytes bordered by scaffolds of mineralized matrix.

The survival of a bone graft is a struggle, a race against impending death. It is generally accepted that the most peripheral cells of the graft are able to survive by diffusion if the recipient site is favourable and these cells exercise a conductor function. The success of all standard bone-grafting procedures is totally dependent on the slow revascularisation of the graft from the bone ends and the surrounding soft tissues, followed by slow resorption of the old bone within the existing framework and its subsequent replacement with new Haversian systems. Primary graft circulation is thought to be dependent either on the ingrowth of new vessels of host origin, i.e. revascularisation, or on anastomoses between host and pre-existing graft vessels, i.e. recirculation.

This report based on delineation of the arterial system with 3 component plastic material on 10 human cadavers describes the arterial supply to the clavicle. The study was performed in 2 parts. One part, which showed the total arterial supply to the clavicle and one part with selective injections of the relevant arteries, with the intention of finding a central nutrient arterial supply to the clavicle. Three arteries were found to supply the clavicle: the suprascapular a.; the thoracoacromial a.; and the internal thoracic (mammary) a. The main supply was primarily periosteal. No nutrient artery was found.

In 44 anesthetized rabbits the femur was perfused in situ through the nutrient artery by blood led through an extracorporal perfusion arrangement from the left carotid artery. Blood inflow, perfusion pressure and intramedullary venous pressure were recorded. At perfusion pressures of 110 to 150 cm of saline (80 to 110 mm of Hg) blood flow in the different animals ranged from 0.1 to 1.2 ml/minXg wet marrow tissue, and intramedullary venous pressure from 10 to 80 cm of saline (7 to 60 mm of Hg). Flow and intramedullary venous pressure both increased with the perfusion pressure whereas flow decreased and intramedullary venous pressure increased when the venous pressure outside the bone increased, showing that in the bone marrow both an arterial and a venous resistance were present. The predominant effect of noradrenaline was to constrict, and of acetylcholine to dilate arterial vessels. No reactive hyperemia could be demonstrated upon occlusion of the arterial inflow. The arterial vessel showed only a weak ability to autoregulate flow. The venous resistance varied greatly from one preparation to another, differing from only a small fraction of-to more than half the total vascular resistance in the bone marrow. It stayed constant or increased with increasing perfusion pressure, thereby causing the pressure-flow relationship curves to differ from convex against the pressure- to convex against the flow axis. The hemodynamic properties demonstrated were explained as being due to the unusual vascular anatomy and the rigid enclosement of the bone marrow

This chapter focuses on the osteogenesis and growth of epiphyseal cartilage. From the time the advancing vessels of the shaft reach a position near the area to be later occupied by the growth cartilage, they slow down their invasiveness as if detained by the incipient columnar arrangement of the chondrocytes. While the Haversian system of the osteons becomes established, the epiphyseal growth cartilage is taking over the responsibility for carrying on the skeletal growth that in the early stages had been assigned to the cartilaginous anlage of the long bones. At the age of two to three years, when most of the growth cartilages are finally organized, the thin layer of bone and calcified cartilage, known as the bone plate, separates the epiphyseal cancellous bone from the immediately adjacent first row of cartilage cells. Over four-fifths of the vessels reaching the growth plate from the M-side are the last ramification of the nutrient artery evenly distributed over the central part of the growth plate.

This chapter discusses the vascular anatomy of bone. It is well known that the blood supply to a long bone comes from three sources: (1) the nutrient artery, (2) the epiphyseal–metaphyseal arteries, and (3) the periosteal arteries. The nutrient arteries vary in number and in position from one bone to another and from one species to another. The ascending branch of the nutrient artery of the tibia is longer and larger than the descending one and, after passing downward and medially, it turns abruptly upward, forming a single or double loop. The accessory nutrient artery, which is smaller than the nutrient artery and somewhat less constant, is occasionally replaced by a branch from the descending artery. The anterior tongue-like portion of the upper tibial epiphysis, which later forms the tibial tuberosity, also receives its arterial supply from the anastomosis behind the quadriceps tendon, by a number of small branches passing down behind the tendon into the epiphysis.

The microcirculation in the bone marrow has been studied in the femur, tibia, and humerus of guinea pigs, rats, and rabbits. Used were whole mounts of bone with bone marrow in situ, perfused and not perfused with India ink, thick sections (0.5 to 1.0 mm) of the same material, and also serially cut histological sections. It is concluded that the major blood supply to the bone marrow is transosteal. Direct intramyeloid connections of the arborizations of the nutrient artery with the sinusoids are rare. The great majority of the terminal capillaries of the nutrient artery enter the bone, where they anastomose with the intraosteal vessels which in turn connect with the sinusoidal network at the osteomyeloid junction. In addition, numerous direct links exist between the periosteal vessels and the vessels in the osteal canals.

This chapter focuses on relative contribution of the three systems of vessels to the blood supply of the long bones. Because of the very large anastomoses, to cause evident changes, vascular suppression must be radical, with the danger of damaging the venous as much as the arterial flow. The chapter presents a study in which 20 animals were used: 15 young and 5 adults. The nutrient vessels were cut, and the blood flow of the bone marrow from the metaphyseal vessels was prevented by plugging the drill holes made at each end of the shaft with the polythene sheath as reported. Necrotic changes appear on the first day following the vascular interruption in the bone marrow cells. All the radii examined showed good filling of the stem of the nutrient artery and of many of its branches.

In fifteen rabbits heniatopoiesis was stimulated by a grave phenylhydrazine anemia. When the hematopoietic activity was maximal as judged from the reticulocyte counts, 6 or 7 days after the first injection of phenylhydrazine, the left femur was perfused in situ through the nutrient artery by blood led through an extracorporal perfusion arrangement from the left carotid artery of the anesthetized animal. The blood flow, the nutrient artery perfusion pressure and the intramedullary venous pressure were recorded. The bone marrow blood flow was greater and varied less than in non-anemic animals. The arterial vessels exhibited a weak ability to auto-regulate flow and acetylcholine caused arterial dilatation showing that neither the grave anemia nor the great hematopoietic activity had brought about a maximal dilatation of the arterial vessels. The venous resistance to bone marrow blood flow was constantly small whereas it has previously been shown to vary greatly in non-anemic animals.

1. Periosteal bone is supplied by periosteal vessels and endochondral bone by the nutrient artery. 2. In the earliest stages of development the metaphysis is supplied by vessels derived only from the nutrient artery. Later, metaphysial arteries derived from the periosteum take over the supply of its peripheral part, the extent of their area of supply progressively increasing. 3. In injected specimens the blood vessels approaching the epiphysial cartilaginous plate end in saccular dilations. Histological sections show these dilations to be blood-filled cartilage lacunae, with no endothelial lining and into which open the blood vessels approaching the epiphysial plate.

In over 90% of 800 experiments in 75 dogs injection directly into the sinus node artery produced sinus bradycardia. Studies to explain this phenomenon included control of temperature, pH, osmolarity, oxygen, and ionic content of injecting solutions. Although unphysiologic variations of any of these are known to produce marked alterations in the sinus mechanism, sinus bradycardia from injection still occurred when they were controlled. Neurogenic mechanisms were excluded by bilateral cervical vagotomy, and by direct perfusion of the sinus node with atropine, hexamethonium, and trimethaphan. Because of the unique anatomic structure of the sinus node, which completely surrounds its nutrient artery, it is suggested that the sinus bradycardia may simply be the consequence of distending the sinus node artery. Implications concerning autoregulation of the normal heart rate are discussed.

W ith the advent of operative approaches to the arteries came the necessity for an exact localization of the lesions of arteriosclerosis. So far, more of such data are available for the lower extremities than for other parts of the body. As more information is gained, it becomes apparent that certain patterns of the arterial involvement may be expected in certain clinical situations. As examples, I may cite the youth of patients with occlusion commencing in the aortic bifurcation, the tendency for diffuse arterial involvement in diabetes, and the association of pulmonary arteriosclerosis with previous pulmonary embolism for hypertension. These associations strongly suggest that arteriosclerosis is not a disease per se, but rather the end result of a variety of causative disease states. There are additional indications that some sites of initial involvement are associated with relative discreteness of disease, others with diffuseness. This, in turn, carries an implication of varying prognosis, since diffuse disease involves many areas in the body, and also shows a tendency to a more rapid progression of disease. I will attetipt in this paper to review what is known of the locations of arteriosclerosis, with some consideration of the means of recognizing the lesions in these places, and I will mention the varying prognoses which attach to different sites of involvement. Anatomic factors in the efects of occlusion. Peculiarities in the anatomic pattern of the arteries, particularly with respect to their anastomotic connections, are important in varying the effects of occlusion from one site to another, and between individuals as well. Ischemia of a limb often fails to follow a glove or stocking distribution because of a relative circumscription that exists for the blood supply to muscle, nerve, and even to portions of the integument.ga For this reason, ischemia may be limited to parts of an extremity, as may be seen in interruption to the vessels of a viscus in the abdominal cavity. Thus, because of occlusion of the hypogastric artery, claudication often persists in the buttock after successful restoration of flow to the rest of the limb. Similarly, a neuritis or a cutaneous infarct may be due to an occlusion of the nutrient artery to those parts quite out of proportion to the vascular status of the limb as a whole. Unexpectedly severe ischemia may occur in organs with multiple sources of supply if the anastomoses between these sources are imperfect. -A detailed consideration

1. Direct injection of contrast material into bone indicates its extreme vascularity, particularly near an epiphysis, and emphasises the extraordinary capacity of the minute periosteal vessels. The nutrient artery of a long bone appears to play little part in its nourishment and may be regarded as a vestigeal structure. 2. The vascular pattern of bone tumours may be investigated by injection of the appropriate artery, and sometimes, if a haemangioma is suspected, by direct injection into the lesion. 3. The examination is easily and quickly carried out by direct arterial puncture under local anaesthesia and injection of 35 per cent diodone. A tourniquet applied distally at the appropriate level is often helpful. 4. A study of the vascular pattern of suspected bone tumours has provided useful information in a positive and negative way, assisting both the diagnosis and the planning of treatment. The pathological diagnosis of some tumours, notably osteosarcomas and haemangiomas, may be made with such assurance that possible dissemination of the tumour by biopsy may be avoided.

This study evaluated the anatomic relationship between the femur and the vessels that arise from the deep femoral artery, that is, the perforating arteries and the nutrient artery. Blue silicone dye was injected through the common femoral artery in 20 fresh human cadavers. An anteromedial and a posterolateral dissection were performed to identify the femoral perforating arteries and the nutrient artery of the femur. The length of the femur and the distances between the tip of the greater trochanter and the perforating arteries and nutrient artery were measured. This study showed that a reliable, clinically applicable topographic relationship exists between the femur and the perforating arteries and the nutrient artery.

Streaming potential is considered one of the most important mechanisms to moderate the function of osteoblasts and osteocytes in bone growth, remodeling and fracture repair. The present study was designed to demonstrate the fluid flow pattern in the cortical bone matrix in an animal model using undecalcified histological techniques. Immediately after injection of ferritin into the tibia nutrient artery of four adult goats, the animals were euthanized. Undecalcified transverse and longitudinal blocks of cortical bone obtained from the tibial diaphysis were immersed in Perl's reagent and embedded in methyl methacrylate. Sections were cut and ground to 30–50 μm thickness for histomorphological evaluation at different magnifications and focusing levels. A serial grinding technique was used to validate the observations made at different focusing levels. As expected, ferritin was observed in the interstitial compartment in both transverse and longitudinal sections. In osteons sectioned transversely, the pattern of centrifugal movement of ferritin marker was demonstrated as single or multiple halos around the Haversian canal. The most apparent halo in osteons with multiple halos was the one found closest to the Haversian canal. The total number of identifiable single or multiple halos increased or was altered when counting was made with higher magnification or at different focusing levels, respectively. Irregular and incomplete ferritin halos indicated structural complexity of the osteons. Overall, the pattern of ferritin movement was consistent with bulk interstitial fluid flow influenced by both hydrostatic pressure and transudation. This study demonstrated for the first time multiple concentric halos of the fluid flow marker ferritin around Haversian canals in the cortical interstitial compartment. The results suggest that the undecalcified technique might be a useful method for qualitative and quantitative studies on cortical fluid flow. Anat Rec 255:380–387, 1999. © 1999 Wiley-Liss, Inc.