Left Bend Research Articles

Refining slip distribution in moderate earthquakes using Sentinel-1 burst overlap interferometry: a case study over 2020 May 15Mw 6.5 Monte Cristo Range Earthquake

SUMMARYAzimuth and range measurements from Synthetic Aperture Radar (SAR) images are commonly used to depict the coseismic deformation of large earthquakes. Azimuth measurements associated with moderate-sized earthquakes are hardly applicable due to their limited accuracy. In this paper, we first explored the capability of Sentinel-1 azimuth measurements to map the coseismic deformation of a moderate earthquake. We used both range and azimuth offset measurements to map the coseismic deformation of the 2020 Mw 6.5 Monte Cristo Range earthquake in Nevada. Optimal dip angles of the two main faults and the slip model were obtained. By adding azimuth displacements as constraints, the inverted slip model reveals shallower and more refined slip than models only constrained by InSAR and GPS data, highlighting the importance of introducing the azimuth measurements to the moderate earthquake. The preferred fault model shows a mixture of left-lateral and normal faulting on the western segment and a left-lateral slip on the eastern segment. We found that the inferred faults might verify the clockwise rotation block model, which has been proposed to accommodate fault slip across the Mina deflection. Moreover, a shallow alluvial basin and the young left-lateral fault within the left bend can potentially be responsible for the orientation and normal slip components in the western fault segment, respectively.

Numerical Simulation Analysis of Lumbosacral Joints during Preparation to Lift Barbell

OBJECTIVE: The aim of this study was to analyze the stress characteristics of the lumbosacral segments of the preparation phase of barbell lifting using finite element method and to provide scientific and objective mechanical factors of lumbosacral joint injury in weightlifters for prevention and treatment of lumbar weightlifting injuries. METHOD: The three-dimensional lumbosacral finite element model was established by reverse engineering method based on DICOM data (L5-S5 segments included). The Von Mise stress trends of lumbosacral bone, soft tissue such as intervertebral disc, ligament were analyzed between normal physiological activities when flexion, extension, left bend, right bend and preparation phase of barbell lifting. CONCLUSION: The vertebral body is the main stress-bearing part during lifting and the intervertebral disc plays a major role in transmitting the load. Long-term repeated high-stress stimulation could cause slight fractures of cancellous bone and end-plate of vertebrae. Interspinous ligament bears more load and is more likely to get injured relative to other ligaments. The force imbalance of the left and right ligament also reveal that minimizing spinal flexion and torsion compound action could reduce the possibility of ligament injury.

Musculoskeletal Modeling and Analysis of Trikonasana.

Context:Yoga has origins speculated to date back to pre-Vedic Indian period and is practiced as a common exercise, both in India as well as all around the world. Although the yoga practices are ages old, there is not much research literature available. Moreover, with the advancement in technology, the modern analysis tools are not used up to their full potential.Aims:This research focuses on developing a framework for analyzing trikonasana, using the optical motion capture system, and validating the noninvasive method for analyzing muscle activity in prominent muscles while performing trikonasana.Subjects and Methods:We have adopted the noninvasive analysis method using optical motion capture system OptiTrack™ for recording the human motion and musculoskeletal modeling software LifeMod™ to analyze the muscle activity while performing trikonasana. Surface electromyography (sEMG) studies were performed using Trigno™ (Delsys Inc.) wireless sEMG sensors to validate the LifeMod simulation results pertaining muscle activation.Results:It was observed that the characteristics of the sEMG match to that of the estimated muscle tension from the architecture used in this study. The muscle groups such as external right obliques muscles, rectus abdominis of the front leg, and gluteus maximus and gluteus medius of the rear leg were observed to undergo major activation during an isometric contraction while performing trikonasana. The magnitudes of the muscle tension during the left bend depict a close resemblance to the muscle tension magnitudes during the right bend.Conclusions:The optical motion capture system and musculoskeletal modeling software can be used to analyze muscle activity in any yoga exercise noninvasively. Since the yoga exercises majorly require the practitioner to maintain a certain posture for a considerable duration, our approach can be used to find the important muscles involved and their corresponding muscle tension when they undergo isometric contraction.

Features preoperative preparation and postoperative treatment of chronic colostasis in children with congenital colon

The article presents an algorithm of preoperative preparation and postoperative rehabilitation of children who have been operated on for chronic colostasis. Objective . To develop the algorithm preoperative and postoperative rehabilitation of children operated on for congenital colon. Material and methods . During the period from 2006 to 2015 at the Department of Pediatric Surgery Bukovina State Medical University at the clinic of pediatric surgery (Chernivtsi) with chronic stasis of large intestine not ganglion genesis was operated on 43 children aged 2 to 18 years.To assess the effectiveness of the proposed treatment, the children were divided into two groups, group I (preoperative and postoperative treatment in the traditional way) - Comparative (21 children), II group (offered improved treatment) - research (22 children). The clinical course was allocated on compensated ,decompensated and subcompensated form of colostasis . Results and discussion . The indications for surgical treatment of congenital colon were - disease progression (increase in the duration of constipation, increased pain and symptoms of fecal toxicity), clinical recurrent bowel obstruction, lack of effect of conservative therapy for 1 year, subject to - the presence of dolichosigma in children older than 5 years ,Payra disease in children older than 13 years. Performed surgical interventions. At case of dolichosigma transanal endorectal down the colon with colo-recto-abouchement by Soave-Boley (n = 6); sigmoidectomy with colo-ascendo-abouchement “end to end” with the formation of the distal copula of colon (n = 10); the intersection of the left colo-diaphragma copula; sigmoidectomy, lowering of colon with descendo-recto-abouchement by Soave-Krivchenia (n = 2); the intersection of the left colo-diaphragma copula, sigmoidectomy with colo-recto-abouchement “end to end” with and formation of the distal copula of colon (n = 11). Disease Payra - resection of the transverse colon and overlay anastomosis “end to end”, and fixation of the left bend colon to the back-side of the abdominal wall in the physiological place (n = 13) Cyilaiditi's syndrome - withdrawal from subphrenic space right parts of colon, resection of the colon right bend with ascendo-transperso-abouchement “end to end” and right-hand colon fixing of ascendo-transperso-bend, hepatopexy (n=1). Conclusions . It is expected that the success of surgical treatment of children with chronic colostasis due to congenital colon depends on the individual chosen method of surgery, preoperative preparation and postoperative treatment. Deleting a particular segment of the colon and the child's need to adapt the organism to new physiological conditions anatomical existence of the colon is the basis for the choice of methods of preoperative preparation and postoperative rehabilitation of children with chronic colostasis. In the preoperative period in children with congenital colon appropriate to include retrograde and orthograde cleaning the colon, diet, and medication support for the proposed algorithm. The complex postoperative rehabilitation measures appropriate to add: intravenous infusions of ozonated physiological NaCl solution at a concentration of 2.5 mkg / l and intrarectally electrical stimulation when faecal incontinence.

The effects of a semiconstrained integrated artificial disc on zygapophyseal joint pressure and displacement.

Measurement of zygapophyseal joint pressure and displacement was performed after placement of a semiconstrained integrated artificial disc (SIAD) in a cadaver model. To understand the likelihood of accelerated zygapophyseal joints degeneration as a result of the implant. A SIAD has been developed to treat lumbar spondylosis secondary to segmental disc degeneration and spinal stenosis. The SIAD replaces the stenotic segment's disc. Previous studies have demonstrated that nonconstrained artificial disc (NAD) replacements fail to achieve their optimal long-term outcomes likely because of significantly increased zygapophyseal joint pressure and displacement at the implanted level. Moreover, clinical studies have reported an increased incidence of zygapophyseal joint degeneration after lumbar disc replacement. Eight cadaver lumbar specimens (L2-L5) were loaded in flexion, neutral, extension, left bend, and right rotation. Zygapophyseal joint pressure and displacement were measured during each of the 5 positions at each of the 3 levels with the ratio of deformation calculated under the different loads. An artificial disc was placed at the L3-L4 level, and the measurements were repeated. After L3-L4 segment implantation, the pressure in the zygapophyseal joint at operative segment was not significantly changed by SIAD and NAD implantation in axial compression and flexion, compared with physiological disc. Notable differences in zygapophyseal joint pressure between the SIAD and NAD were identified at the operative level in extension, left bend, and right rotation. The adjacent-level effect of NAD was significantly greater than that of SIAD. The ratio of deformation difference between the 2 discs was increased by load experienced in extension, flexion, left bend, and right rotation. The SIAD provided a superior biomechanical milieu for zygapophyseal joints at the implanted and adjacent levels compared with NAD, which may avoid the acceleration of postoperative zygapophyseal joint degeneration. 1.

Numerical study of 3D flow at right-angled confluences with and without upstream planform curvature

The purpose of this paper is to study the individual and combined effect of upstream planform curvature and difference in bed elevations at the tributary entrance to the confluence on the flow in the confluence hydrodynamics zone. To do this, flow at right-angled confluences with three planforms and four values of bed elevation discordance ratio (ΔzT/hd) is simulated using a three-dimensional (3D) numerical model. Three confluence planforms include confluences with the (1) straight tributary canal (SC), (2) right bend (RB) and (3) left bend (LB) in the tributary. Four ΔzT/hd values in the range [0.0, 0.5] include both concordant and discordant beds' confluences. Overall, nine cases with the straight main canal are considered. Special attention is paid to the flow deflection and flow separation zones since the former affects transfer of momentum from the tributary to the main canal and the latter affects transport capacity of the post-confluence channel. Comparison of the results reveals that the influence of RB in the tributary is practically negligible in comparison to the straight canal case. With the increasing difference in bed elevations between the tributary and main canals (ΔzT), the presence of LB strengthens 3D flow and the structure of the recirculation zone is destroyed.

Biomechanical Evaluation of the X-Stop Device for Surgical Treatment of Lumbar Spinal Stenosis

Controlled experimental study. To evaluate the kinematical effects of X-Stop device on the spinal process at the operated and the adjacent segments before and after X-Stop surgeries during various weight-bearing postures in elderly patients with lumbar spine stenosis. The mechanism of interspinous process (ISP) devices is to directly distract the ISP of the implanted level to indirectly decompress the intervertebra foramen and spinal canal. Few studies have investigated the changes of ISP gap caused by X-Stop implantation using magnetic resonance imaging or radiography, but the effect of X-Stop surgery on the kinematics of spinous processes during functional activities is still unclear. Eight patients were tested before and, on average, 7 months after surgical implantation of the X-Stop devices using a combined computed tomography/magnetic resonance imaging and dual fluoroscopic imaging system during weight-bearing standing, flexion-extension, left-right bending, and left-right twisting positions of the torso. The shortest distances of the ISPs at the operated and the adjacent levels were measured using iterative closest point method and was dissected into vertical (gap) and horizontal (lateral translation) components. At the operated levels, the shortest vertical ISP distances (gap) significantly (P<0.05) increased by 1.5 mm during standing, 1.2 mm during left twist, 1.3 mm during extension, and 1.1 mm during flexion, whereas they also increased yet not significantly (P>0.05) in right twist, left bend, and right bend after the X-Stop implantation. The lateral translations were not significantly affected. At both cephalad and caudad adjacent levels, the ISP distances (vertical and horizontal) were not significantly affected during all postures after X-Stop implantation. The findings of this study indicate that implantation of the X-Stop devices can effectively distract the ISP space at the diseased level without causing apparent kinematic changes at the adjacent segments during the studied postures.

Basin geometry and cumulative offsets in the Eastern Transverse Ranges, southern California: Implications for transrotational deformation along the San Andreas fault system

The Eastern Transverse Ranges, adjacent to and southeast of the big left bend of the San Andreas fault, southern California, form a crustal block that has rotated clockwise in response to dextral shear within the San Andreas system. Previous studies have indicated a discrepancy between the measured magnitudes of left slip on through-going east-striking fault zones of the Eastern Transverse Ranges and those predicted by simple geometric models using paleomagnetically determined clockwise rotations of basalts distributed along the faults. To assess the magnitude and source of this discrepancy, we apply new gravity and magnetic data in combination with geologic data to better constrain cumulative fault offsets and to define basin structure for the block between the Pinto Mountain and Chiriaco fault zones. Estimates of offset from using the length of pull-apart basins developed within left-stepping strands of the sinistral faults are consistent with those derived by matching offset magnetic anomalies and bedrock patterns, indicating a cumulative offset of at most ~40 km. The upper limit of displacements constrained by the geophysical and geologic data overlaps with the lower limit of those predicted at the 95% confidence level by models of conservative slip located on margins of rigid rotating blocks and the clockwise rotation of the paleomagnetic vectors. Any discrepancy is likely resolved by internal deformation within the blocks, such as intense deformation adjacent to the San Andreas fault (that can account for the absence of basins there as predicted by rigid-block models) and linkage via subsidiary faults between the main faults.

Morphology, structure and evolution of California Continental Borderland restraining bends

Abstract Exceptional examples of restraining and releasing bend structures along major strike-slip fault zones are found in the California continental Borderland. Erosion in the deep sea is diminished, thereby preserving the morphology of active oblique fault deformation. Long-lived deposition of turbidites and other marine sediments preserve a high-resolution geological record of fault zone deformation and regional tectonic evolution. Two large restraining bends with varied structural styles are compared to derive a typical morphology of Borderland restraining bends. A 60-km-long, 15° left bend in the dextral San Clemente Fault creates two primary deformation zones. The southeastern uplift involves ‘soft’ turbidite sediments and is expressed as a broad asymmetrical ridge with right-stepping en echelon anticlines and local pull-apart basins at minor releasing stepovers along the fault. The northwest uplift involves more rigid sedimentary and possibly igneous or metamorphic basement rocks creating a steep-sided, narrow and more symmetrical pop-up. The restraining bend terminates in a releasing stepover basin at the NW end, but curves gently into a transtensional releasing bend to the SE. Seismic stratigraphy indicates that the uplift and transpression along this bend occurred within Quaternary times. The 80-km-long, 30–40° left bend in the San Diego Trough–Catalina fault zone creates a large pop-up structure that emerges to form Santa Catalina Island. This ridge of igneous and metamorphic basement rocks has steep flanks and a classic ‘rhomboid’ shape. For both major restraining bends, and most others in the Borderland, the uplift is asymmetrical, with the principal displacement zone lying along one flank of the pop-up. Faults within the pop-up structure are very steep dipping and subvertical for the principal displacement zone. In most cases, a Miocene basin has been structurally inverted by the transpression. Development of major restraining bends offshore of southern California appears to result from reactivation of major transform faults associated with Mid-Miocene oblique rifting during the evolution of the Pacific–North America plate boundary. Seismicity offshore of southern California demonstrates that deformation along these major strike-slip fault systems continues today.

Effects of polyaxial pedicle screws on lumbar construct rigidity.

Pedicle screw constructs have been shown to increase fusion rates in the lumbar spine. Manufacturers have created pedicle screws with one or two degrees of freedom built into the screw head to allow for easier incorporation of the interlocking rod, but the effects of these screws on construct stiffness has not been tested. The purpose of this study is to compare and contrast the stiffness of lumbar pedicle screw constructs with and without the use of polyaxial pedicle screws. Nontapered, self-taping pedicle screws (6.0-mm diameter x 30-mm length, titanium) were used in the fixation of porcine spines from L3-L5. Group 1 (n = 5) contained six standard pedicle screws from one manufacturer. Group 2 (n = 5) contained six standard pedicle screws from a second manufacturer. Group 3 (n = 5) contained four standard pedicle screws placed at L3 and L5, as well as two polyaxial screws placed at L4. Group 4 (n = 5) contained six polyaxial pedicle screws. A rotational variable differential transformer was used to record angular displacement between vertebrae in the construct as it is loaded in flexion, extension, right bend, left bend, clockwise torque, and counterclockwise torque. Stiffness curves were linear throughout the range of applied force. The average r2 value for the generated stiffness graphs was 0.94 (SD = 0.06). No construct failure occurred during any of the testing. There were no significant differences (p < 0.05, two-way analysis of variance) in moment versus angle noted in any of the four groups tested. For torque tests, the all-polyaxial screw constructs showed significantly increased stiffness compared with the other groups. The current study has shown that the incorporation of polyaxial screws in pedicle screw constructs did not significantly decrease the construct stiffness. There is a suggestion that the use of all polyaxial screws may increase the resistance to torque by allowing better purchase of intervertebral rods.

Abrupt along‐strike change in tectonic style: San Andreas Fault zone, San Francisco Peninsula

Seismicity and high‐resolution aeromagnetic data are used to define an abrupt change from compressional to extensional tectonism within a 10‐ to 15‐km‐wide zone along the San Andreas fault on the San Francisco Peninsula and offshore from the Golden Gate. This 100‐km‐long section of the San Andreas fault includes the hypocenter of the Mw = 7.8 1906 San Francisco earthquake as well as the highest level of persistent microseismicity along that ∼470‐km‐long rupture. We define two distinct zones of deformation along this stretch of the fault using well‐constrained relocations of all post‐1969 earthquakes based a joint one‐dimensional velocity/hypocenter inversion and a redetermination of focal mechanisms. The southern zone is characterized by thrust‐ and reverse‐faulting focal mechanisms with NE trending P axes that indicate “fault‐normal” compression in 7‐ to 10‐km‐wide zones of deformation on both sides of the San Andreas fault. A 1‐ to 2‐km‐wide vertical zone beneath the surface trace of the San Andreas is characterized by its almost complete lack of seismicity. The compressional deformation is consistent with the young, high topography of the Santa Cruz Mountains/Coast Ranges as the San Andreas fault makes a broad restraining left bend (∼10°) through the southernmost peninsula. A zone of seismic quiescence ∼15 km long separates this compressional zone to the south from a zone of combined normal‐faulting and strike‐slip‐faulting focal mechanisms (including a ML = 5.3 earthquake in 1957) on the northernmost peninsula and offshore on the Golden Gate platform. Both linear pseudogravity gradients, calculated from the aeromagnetic data, and seismic reflection data indicate that the San Andreas fault makes an abrupt ∼3‐km right step less than 5 km offshore in this northern zone. A similar right‐stepping (dilatational) geometry is also observed for the subparallel San Gregorio fault offshore. Persistent seismicity and extensional tectonism occur within the San Andreas right stepover region and at least 15 km along‐strike both to the SE and NW. The 1906 San Francisco earthquake may have nucleated within the San Andreas right stepover, which may help explain the bilateral nature of rupture of this event. Our analysis suggests two seismic hazards for the San Francisco Peninsula in addition to the hazard associated with a M = 7 to 8 strike‐slip earthquake along the San Andreas fault: the potential for a M ≈ 6 normal‐faulting earthquake just 5–8 km west of San Francisco and a M = 6+ thrust faulting event in the southern peninsula.

Rise and fall of the southern Santa Cruz Mountains, California, from fission tracks, geomorphology, and geodesy

The Santa Cruz Mountains are closely associated with a left bend along the right‐lateral San Andreas fault. The Loma Prieta area on the northeast side of the San Andreas consists of fault‐bounded blocks that rise along active, deeply rooted, reverse and oblique‐slip faults. Six samples from a transect across this area yield concordant apatite fission track ages averaging 4.6±0.5 Ma. These ages date the time of cooling below ∼110°C and suggest that about 3 km of unroofing has occurred over the last 4.6 m.y. Allowing for current elevations of about 1 km, this suggests an average uplift rate of the order of 0.8 mm/yr over the last 4.6 m.y. To further define the extent and distribution of this young uplift, we used morphometric analyses of the youthful topography of the area. Steep drainage slopes and high local relief indicate that the area northeast of the San Andreas forms a well‐defined zone of high uplift. In contrast, the region on the southwest side of the San Andreas is characterized by broad upwarping and folding, more subdued topography, old fission track ages, and mean Quaternary uplift rates of 0.1–0.4 mm/yr. Geodetic data (1906 San Francisco earthquake and subsequent strain transients, 20 years of interseismic deformation, 1989 Loma Prieta earthquake, and 2 years of post‐Loma Prieta earthquake strain) show that the Southern Santa Cruz Mountains repeatedly rise and subside through a complex sequence of bay area deformation events. An additional deformation element that involves reverse slip averaging 2–3 mm/yr along the Foothills thrust system must occur to explain the longer‐term uplift pattern in the Loma Prieta area since the late Pliocene. The asymmetry in deformation on opposite sides of the San Andreas probably reflects the contrasting rock types on opposite sides of the fault, the influence of preexisting structures, and the interaction with neighboring faults of the San Andreas system.

Effect of Immobilization and Configuration on Lumbar Adjacent-Segment Biomechanics

The motion and facet load changes at the adjacent segment after lumbosacral immobilization (with different angles) were quantified in vitro using canine spines. Changes were examined under flexion, extension, and lateral bending. An increase (extension: 62%; flexion: 85%; left bend: 30%; right bend 26%) in motion at the adjacent segment was found for all motions after immobilization. Adjacent-segment facet load remained constant under any load state or immobilized configuration. For all configurations, the facet contact site impinged in extension, remained unchanged in left bending, and moved superiorly in right bending. This study has shown that after immobilization the facet contact patterns at the adjacent segment changed, load was unchanged, and segmental motion increased when the lumbar spine reproduced the same range of motion. The configuration of the immobilized segments had no effect on these changes.

Effect of Immobilization and Configuration on Lumbar Adjacent-Segment Biomechanics

The motion and facet load changes at the adjacent segment after lumbosacral immobilization (with different angles) were quantified in vitro using canine spines. Changes were examined under flexion, extension, and lateral bending. An increase (extension: 62%; flexion: 85%; left bend: 30%; right bend 26%) in motion at the adjacent segment was found for all motions after immobilization. Adjacent-segment facet load remained constant under any load state or immobilized configuration. For all configurations, the facet contact site impinged in extension, remained unchanged in left bending, and moved superiorly in right bending. This study has shown that after immobilization the facet contact patterns at the adjacent segment changed, load was unchanged, and segmental motion increased when the lumbar spine reproduced the same range of motion. The configuration of the immobilized segments had no effect on these changes.

Tectonic geomorphology of the San Andreas fault zone in the southern Indio Hills, Coachella Valley, California

Geomorphic investigation of the San Andreas fault zone in the Indio Hills indicates many tectonically produced landforms, including beheaded streams, right-lateral deflected and offset streams, sags, shutter ridges, pressure ridges, and fault scarps. Near Biskra Palms, an alluvial fan-pediment complex has an apparent cumulative offset of about 0.7 km along the Mission Creek fault zone (north branch, San Andreas fault). Many of the tectonic landforms, as well as the fracture pattern that has developed during the Pleistocene, are explainable by simple shear or uplift associated with a small left bend in the main trace of the Mission Creek fault. The ratio of vertical to horizontal displacement in the vicinity of the bend is about 0.04. Exposed in Pushawalla Canyon, 5 km northwest of the alluvial fan-pediment complex, are: (1) a sequence of stream terraces, (2) folded Plio-Pleistocene fanglomerates, and (3) an example of stream capture following a right lateral deflection or offset of several hundred metres. A left step of the Mission Creek fault in Pushawalla Canyon is a probably cause of folds and sporadic uplift that produced the stream terraces. Possible cause of recent stream capture are: (1) juxtaposition of Pushawalla Canyon with a relict canyon moving northwestward along the Mission Creek fault, or (2) right-lateral deflection or offset of Pushawalla Canyon along the fault, with simultaneous headward erosion of a shorter, steep stream flowing toward the Coachella valley. Estimation of a slip rate and identification of paleoseismicity for the San Andreas fault in the Indio Hills is difficult. However, degree of topographic dissection, formation, and preservation of desert pavement, and relative soil profile development suggest that the age of the offset fan may be as old as 70,000 yr but that most likely it is on the order of 20,000 to 30,000 yr. These age estimates for the offset fan indicate a minimum slip rate for the San Andreas fault of 10 to 35 mm/yr, with about 23 to 35 mm/yr the most likely. The pattern of observed offset drainages is complex, but suggests that during the past few thousand years creep events or moderately large earthquakes have periodically produced several metres of right-lateral displacement.

THE HANDITOME: A SIMPLE DEVICE FOR CUTTING SECTIONS

To facilitate the cutting of sections without the use of a microtome, I have devised a simple instrument which is called a handitome. In principle the handitome is a clamp 11 cm. long and 2.5 cm. high, except 2 cm. from the jaw where the height is 1 cm. The clamp is held together by a screw and a spring which are placed 5 cm. from the tip of the jaw. The distal 0.5 cm. of the left jaw and 1 cm. of the right jaw are bent so that, when the clamp is open 0.5 cm., the right and left bend are in line and form a right angle with the straight arms (fig. 1). The essential requirements which must be observed in the construction of the handitome are that the angles must be sharp and the lateral flares be on a straight line when the jaws are

THE PURPOSES OF URETER-CATHETERISM— PRESENTATION OF URETER-CYSTOSCOPE FOR MALE AND FEMALE.

The purposes of ureter-catheterism in connection with the cystoscope are twofold: For diagnosis and for treatment. DIAGNOSIS. To locate the origin of pus, blood, tubercular products or bacilli, the various pyogenic infections, abnormally desquamated epithelium, etc., as to whether they come from (a) the bladder, (b) the right ureter, (c) the left ureter, (d) the right kidney (e) the left kidney, (f) the right or (g) the left peri-renal space and communicating with the corresponding kidney or ureter. To recognize and locate obstructive conditions in the right or left ureter, from (a) stricture, (b) stone, (c) adjacent tumors, (d) bend or kink in the ureter from movable or dislocated kidney, (e) valvular junction of ureter and pelvis. To determine (a) the presence of two kidneys, (b) if only one, which is absent. To determine the number of ureters present. To determine the functional activity of each kidney separately and relatively,