Thick Fat Layer Research Articles

Development and growth of the temporal fascia: a histological study using human fetuses.

The temporal fascia is a double lamina sandwiching a thick fat layer above the zygomatic bony arch. To characterize each lamina, their developmental processes were examined in fetuses. We observed histological sections from 22 half-heads of 10 mid-term fetuses at 14-18 weeks (crown-rump length, 95-150 mm) and 12 near-term fetuses at 26-40 weeks (crown-rump length, 215-334 mm). The superficial lamina of the temporal fascia was not evident at mid-term. Instead, a loose subcutaneous tissue was attached to the thin, deep lamina of the temporal fascia covering the temporalis muscle. At near-term, the deep lamina became thick, while the superficial lamina appeared and exhibited several variations: i) a mono-layered thick membrane (5 specimens); ii) a multi-layered membranous structure (6) and; iii) a cluster of independent thick fasciae each of which were separated by fatty tissues (1). In the second and third patterns, fatty tissue between the two laminae was likely to contain longitudinal fibrous bands in parallel with the deep lamina. Varying proportions of the multi-layered superficial lamina were not attached to the zygomatic arch, but extended below the bony arch. Whether or not lobulation or septation of fatty tissues was evident was not dependent on age. The deep lamina seemed to develop from the temporalis muscle depending on the muscle contraction. In contrast, the superficial lamina developed from subcutaneous collagenous bundles continuous to the cheek. Therein, a difference in development was clearly seen between two categories of the fasciae.

Survival strategies of marine mammals in extreme environments: A study of whales and seals

Extreme environments, characterized by challenges such as sub-zero temperatures, limited sunlight and scarce resources, pose great challenges to organisms, including marine mammals. Marine mammals have evolved to live in extreme environments.These mammals are highly tolerant of cold and stress and can continue to breathe for long periods of time. The method used in this article is literature study by analyzing several articles. Marine mammals such as seals have a thick layer of fat. This adaptation reduces heat loss and helps maintain body temperature in cold environments. Cetaceans, like whales, have undergone fundamental morphological and molecular changes to adapt to the aquatic environment. Characteristic of these whales are their baleen plates and ability to communicate through vocal signals, forage socially, and migrate across much of the globe.

Verification of effect of analytical conditions of shear wave velocity on ability to evaluate microstructure

In this study, the relationship between the analytical conditions of shear wave velocity (SWV) and the evaluation ability of microstructure were verified by FDTD simulation. By adding acoustic radiation force (ARF) to the left edge of the simulation space, which mimicked various fatty livers with different fat mass, shear waves propagating in the lateral direction were simulated in each liver. SWV was calculated using the time difference calculated by the cross-correlation method from two timewaves laterally located in the simulation. By varying the resolution of the SWV evaluation, the effect of scattering and refraction of shear waves in fat droplets, etc. on the macroscopic shear propagation was evaluated. Although shear waves could be evaluated stably when tracking shear waves at the spatial step (time width) of the clinical device level, the effects of individual fatty substances were strongly indicated when tracking in the microscopic sense of 10 μm (50 ns). When there was a thick fat layer or a sparse muscle layer near the body surface, the irradiation of ARFI did not work as expected and the evaluation accuracy of SWV decreased.

Effects of body parameters on renal cortical stiffness measured by shear-wave elastography in patients with kidney transplantation.

The results of elastic imaging in evaluating the function and histopathological changes of allogeneic renal transplantation are contradictory, one of the important reasons may be that there are differences in human parameters related to kidney transplantation among individuals. The purpose of this study is to explore the related human body parameters on shear-wave elastography (SWE) effects on quantitative stiffness of graft cortex. From March 2021 to November 2021, a total of 63 patients with allogeneic kidney transplantation in the Department of Ultrasonography, Third Xiangya Hospital, Central South University, were selected to collect the parameters of two-dimensional, color Doppler and SWE. The subjects were divided into a <20% group and a 20%-30% group according to the variation of cortical hardness measurement. Mann Whitney U test was used to compare the differences in relevant human parameters, and Spearman rank correlation was used to analyze the correlation between relevant human parameters and cortical hardness of transplanted kidney. There was no significant difference between the 2 groups in age, sex, postoperative time, resistance index of interlobar artery, SCr, blood uric acid, ratio of fat layer to muscle layer, and BMI (all P>0.05). Compared with the <20% group, the patients in the 20%-30% group had smaller cortical hardness of the transplanted kidney, greater total distance between the transplanted kidney and the skin surface, and thicker fat layer or muscle layer in front of the transplanted kidney (all P<0.05). The age of patients, the total distance from the transplanted kidney to the skin surface, the thickness of fat layer and muscle layer, the ratio of fat layer to muscle layer, BMI, and the variation of cortical hardness were significantly negatively correlated with the cortical hardness of the transplanted kidney (all P<0.05). Human parameters relevant to kidney transplantation affect the accuracy of SWE in measuring the cortical hardness of the transplanted kidney. It is very important to obtain the highly stabile elastic measurement value and interpret the elastic measurement results according to different levels of human body related parameters in combination with individual conditions.

The influence of protected fat in supplements on the performance and carcass characteristics of Nellore beef bulls in tropical pasture.

The finishing stages for uncastrated Nellore beef cattle on tropical pasture often produce high yielding carcasses with minimal fat cover. This study aimed to evaluate the performance and carcass characteristics of uncastrated Nellore beef bulls fed a diet containing rumen-protected fat during the rainy period for 210days. Eighty Nellore beef bulls with 28months of age, and an initial live weight of 416kg ± 16kg, were allocated into eight paddocks (7.0ha), totaling 56ha, at 10 animals/paddock, in a continuous-grazing system. The pasture characteristics, performance production, loin-eye area (cm2), subcutaneous fat thickness (mm), and rump fat thickness were evaluated. There was no effect (P > 0.05) on the average total weight gain (203.00kg) and average daily gain (0.98kg/day). On the other hand, the subcutaneous fat thickness and rump fat thickness were 42.8% and 49.5% greater, respectively, when the animals were fed a diet containing rumen-protected fat inclusion (P < 0.05). Supplementation with rumen-protected fat provided a thicker fat layer in the carcass of Nellore beef bulls grazing on tropical pasture during the rainy period.

Physico-chemical and rheological properties of Lebanese kishk powder, a dried fermented milk-cereal mixture

Kishk is a traditional fermented milk-cereal mixture, widely consumed in Lebanon. Twenty Lebanese kishk powder samples were collected from artisanal producers in four Lebanese regions, in order to assess the effect of milk base and cereals on their physicochemical properties, functional and rheological properties. Milk type affected the fat content and color parameters of kishk samples. Multi-scale exploration of kishk microstructure revealed a complex network of macroconstituents (milk protein and wheat starch) embedded in a thick layer of fat. The mechanism of kishk rehydration was then exploited by analyzing the water sorption isotherms and observing the morphometric changes in the particles of this powder subjected to different relative humidities. From powder rheology measurements, kishk showed an intermediate flowability behavior and cohesiveness, associated to its high fat content as a binder between the particles.

Sportoló és nem sportoló fiúk regionális zsíreloszlásának mintázata

The study deals with the connection between sexual maturation and fat accumulation during male puberty. The purposes were: (1) to follow the alterations in regional body adiposity during genital development; (2) to reveal the differences in fat patterning of athletes and non-athletes, (3) to analyze the influence of genital maturation and sport activity on the indices of fatness in pubertal boys. The subjects were athlete (n=803) and non-athlete (n=989) boys. They were grouped by the stages of genital development. Regional fat distribution was examined on the basis of skinfolds. The amount of subcutaneous and visceral abdominal adipose tissues was assessed by regression equations of Brambilla and co-workers. The effect of genital development and sport activity on fat compartments was studied by multivariate ANOVA. The centralization tendency in adipose tissue was revealed by the progressing of genital development. Non-athletes accumulated more relative subcutaneous fat on their extremities, while athletes did it on their trunk. Adjusted to the absolute body fat mass, visceral adipose tissue increased faster in athletes than in non-athletes. The multivariate model proved that genital maturation affected the regional fat distribution. During sexual maturation the regional apposition trend of body fat was similar for athletes and non-athletes. The differences between athletes’ and non-athletes’ fat pattering emerged in the relative distributions. The relatively thicker fat layer on the trunk served better the extended energy supply for athletes. The effect of sexual maturation was the largest on the visceral adipose tissue, while sport activity influenced the subcutaneous adipose tissue better on the extremities.

Optical-resolution photoacoustic imaging through thick tissue with a thin capillary as a dual optical-in acoustic-out waveguide

We demonstrate the ability to guide high-frequency photoacoustic waves through thick tissue with a water-filled silica-capillary (150 μm inner diameter and 30 mm long). An optical-resolution photoacoustic image of a 30 μm diameter absorbing nylon thread was obtained by guiding the acoustic waves in the capillary through a 3 cm thick fat layer. The transmission loss through the capillary was about −20 dB, much lower than the −120 dB acoustic attenuation through the fat layer. The overwhelming acoustic attenuation of high-frequency acoustic waves by biological tissue can therefore be avoided by the use of a small footprint capillary acoustic waveguide for remote detection. We finally demonstrate that the capillary can be used as a dual optical-in acoustic-out waveguide, paving the way for the development of minimally invasive optical-resolution photoacoustic endoscopes free of any acoustic or optical elements at their imaging tip.

CLSM study of layers in laminated dough: Roll out of layers and elastic recoil

It has been thought that all fat and dough layers in laminated dough had the same thickness at the end of lamination. Moreover dough rheology (taking into account elastic recoil) is too complex to generalize calculation of the final thickness of the dough after lamination. Confocal laser scanning microscopy can differentiate the fat from the dough when combined with fluorophore staining (Nile Red and Alexa), and an algorithm was applied to quantify their respective thicknesses. When fat consistency was close to that of dough, the median thickness of fat was fairly close to theoretical values. Successive sheeting steps resulted in homogenization of layer thicknesses. The surface area of fat in relation to paste was greater than expected, especially for low numbers of sheeting steps, and also for samples with higher numbers of sheeting steps, presenting an exceptionally thick layer of fat (including that produced by back flow). Elastic recoil was between 20 and 90% higher than the targeted roll out; no significant effect of a harder fat consistency was found. Elastic recoil was less when the amount of fat in the sample was greater.

Shoulder ulcers in sows are genetically correlated to leanness of young pigs and to litter weight

The aim of this study was to estimate the heritability for shoulder ulcers (SU) and sows' body condition at weaning (BCw), and the genetic correlations between these traits and some production and reproduction traits included in the current breeding goal of sow lines. The analyses were based on data on Swedish purebred Yorkshire from nucleus as well as multiplier herds. The estimated heritabilities were for BCw 0.21, and for SU 0.13. Significant genetic correlations were found between sidefat thickness (at 100 kg) and BCw (thicker fat layer at 100 kg – better condition at weaning), between sidefat thickness and SU (thicker fat layer – less SU), between litter weight at 3 weeks and BCw (heavier litter – lower body condition) and between litter weight at 3 weeks and SU (heavier litter – more SU). The genetic correlation between BCw and SU was also significant (lower body condition – more SU).

Accurary of Oxygen Desaturation of Hemoglobin in Muscle by Near-Infrared Oximeters

Dear Editor-in-Chief A recent article (1) has demonstrated that maximal lactate steady state can be accurately determined in healthy subjects in response to an incremental cycling test up to exhaustion based on measures by near-infrared spectroscopy (NIRS) of vastus lateralis deoxygenated hemoglobin concentration (HHb) (considered as an index of O2 extraction). Although the proposed method is very interesting in sports science, the presentation of the NIRS technique and the NIRS muscle oxygenation data are incomplete and raise questions about some of the conclusions drawn by the authors. For measuring muscle oxygenation, Bellotti et al. (1) used a multidistance frequency-domain oximeter (rather than a continuous-wave instrument as stated by the authors), commercially introduced in 1998, and equipped with a rigid muscle probe in which four source-detector distances ranging from 2 to 3.5 cm implement a multidistance data collection (2). Given typical values of the near-infrared optical properties in muscle tissue (absorption coefficient approximately 0.08 cm−1, reduced scattering coefficient approximately 6 cm−1), the mean and maximal penetration depths can be estimated at about 1 and 2–2.5 cm, respectively (5). Accordingly, the continuous-wave technique adopted in the most recent portable/wearable/wireless devices provides a typical depth sensitivity of approximately 1.5 cm (3) and not 3 cm as stated by Bellotti et al. (1). Although NIRS undoubtedly offers several advantages for muscle studies (4), some questions (other than its applicability to subjects with a thick fat layer) are still open: for instance, 1) the contribution of myoglobin desaturation to the NIRS signal during exercise; 2) the effect of scattering changes during exercise; 3) the effect of changes in skin perfusion, particularly during prolonged exercise; and 4) the lack of standardization for NIRS instrumentation (3). Bellotti et al. (1) as well as other researchers in the past have evaluated the kinetics of muscle oxygenation using continuous-wave or frequency-domain oximeters and have drawn the physiological conclusions of their studies on the basis of the interpretation of the changes in HHb only. HHb changes (reported erroneously by the authors in their Fig. 1 as millimolar instead of micromolar) might represent tissue oxygenation changes only when tHb (tHb = O2Hb + HHb) is stable (3). Unfortunately, Bellotti et al. (1) did not report or comment on changes in tHb that are necessary for a correct interpretation of muscle oxygenation changes. NIRS oximeters offer the great advantage to also provide measurements of muscle hemoglobin saturation (SmO2), expressed in percent (%). This parameter reflects the dynamic balance between O2 supply in the muscle microcirculation and O2 consumption demand by the muscle. In addition, SmO2 measurements are unaffected by a systematic bias in absorption measurements and, compared with HHb measurements, are not as sensitive to the optical coupling to tissue and to the superficial skin/fat layers. As recently suggested (6), the combined measurement of changes in HHb, O2Hb, and SmO2 allows for novel comparisons of these variables during exercise. Considering the significant physiological information content of NIRS measurements, we recommend that NIRS studies report HHb, O2Hb, and SmO2 data for a comprehensive characterization and thorough discussion of the results. Valentina Quaresima Marco Ferrari Department of Life, Health, and Environmental Sciences University of L’Aquila L’Aquila, Italy Sergio Fantini Department of Biomedical Engineering Tufts University Medford, MA

Treatment of Posttraumatic Fingertip Pain Using a Great Toe Pulp Graft

Complications of fingertip injury include pain, hyper- or dyssensitivity, cold intolerance, and fingertip atrophy. Especially in cases of soft-tissue defect or atrophy which result from crushing injury, fingertip pain often occurs when a finger touches the objects. To overcome this problem, several techniques including local flaps or free flaps were suggested. But these methods require intricate and multistaged procedures.Twelve patients who had fingertip pain with pulp atrophy were treated with pulp graft between March 2004 and March 2006. Under the local anesthesia, we made a fish-mouth incision at the most prominent portion of fingertip and elevated volar flaps. Composite tissue was harvested from the lateral aspect of great toe, and inserted between the previously elevated volar flaps. The harvested composite pulp tissue contained about 3- to 5-mm thick fat layer. Moisture dressing was performed. The visual analogue scale (VAS) was used to evaluate the degree of pain postoperatively. The follow-up period was in the range between the 12 and 24 months (average, 19 months). Pre- and postoperative differences in VAS scores were analyzed for statistical significance, using the Wilcoxon rank sum test. In addition, patients were asked about their level of satisfaction with the procedure. To evaluate the postoperative sensation of the graft, we performed the Semmes-Weinstein monofilament test, and static and dynamic 2-point discrimination test at 1 year postoperatively.The size of the graft was ranged from 276 mm (12 × 23 mm) to 750 mm (25 × 30 mm). At final follow-up review, 5 patients were very satisfied and 7 were satisfied. Atrophy of the fingertip was also improved. Fingertip pain reduced from 8.5 preoperative to 3.1 postoperative on VAS. These improvements were statistically significant. Semmes-Weinstein monofilament test was green (∼2.83) in 9 patients (75%) and blue (3.22-3.61) in 3 of 12 patients (25%). Static and dynamic 2-point discrimination test results came out as 6 and 5 mm, respectively.Composite graft applied to the fingertip is a simple technique, and gives few complications. This procedure can be performed under local anesthesia and gives a fairly high degree of satisfaction to patients. We believe this method is useful for treating fingertip pain with atrophy of pulp.

Evaluation of alignment error due to a speed artifact in stereotactic ultrasound image guidance

Ultrasound (US) image guidance systems used in radiotherapy are typically calibrated for soft tissue applications, thus introducing errors in depth-from-transducer representation when used in media with a different speed of sound propagation (e.g. fat). This error is commonly referred to as the speed artifact. In this study we utilized a standard US phantom to demonstrate the existence of the speed artifact when using a commercial US image guidance system to image through layers of simulated body fat, and we compared the results with calculated/predicted values. A general purpose US phantom (speed of sound (SOS) = 1540 m s−1) was imaged on a multi-slice CT scanner at a 0.625 mm slice thickness and 0.5 mm × 0.5 mm axial pixel size. Target-simulating wires inside the phantom were contoured and later transferred to the US guidance system. Layers of various thickness (1–8 cm) of commercially manufactured fat-simulating material (SOS = 1435 m s−1) were placed on top of the phantom to study the depth-related alignment error. In order to demonstrate that the speed artifact is not caused by adding additional layers on top of the phantom, we repeated these measurements in an identical setup using commercially manufactured tissue-simulating material (SOS = 1540 m s−1) for the top layers. For the fat-simulating material used in this study, we observed the magnitude of the depth-related alignment errors resulting from the speed artifact to be 0.7 mm cm−1 of fat imaged through. The measured alignment errors caused by the speed artifact agreed with the calculated values within one standard deviation for all of the different thicknesses of fat-simulating material studied here. We demonstrated the depth-related alignment error due to the speed artifact when using US image guidance for radiation treatment alignment and note that the presence of fat causes the target to be aliased to a depth greater than it actually is. For typical US guidance systems in use today, this will lead to delivery of the high dose region at a position slightly posterior to the intended region for a supine patient. When possible, care should be taken to avoid imaging through a thick layer of fat for larger patients in US alignments or, if unavoidable, the spatial inaccuracies introduced by the artifact should be considered by the physician during the formulation of the treatment plan.

TU‐C‐351‐02: Alignment Error Due to Speed Artifact in Stereotactic Ultrasound Image Guidance

Purpose: US image guidance systems which are calibrated for soft tissue applications will introduce errors in depth‐from‐transducer representation when used in media with a different speed of sound propagation (e.g. fat). In this study we utilized a standard US phantom to demonstrate the existence of the speed artifact when using a commercial US image guidance system to image through simulated layers of body fat, and compared the results with calculated/predicted values. Method and Materials A General Purpose Ultrasound Phantom (speed of sound‐SOS = 1540 m/s) Model ATL 040 (CIRS, Norfolk, VA) was imaged on a LightSpeed RT CT scanner (GE Health Care, Waukesha, WI) at 0.625‐mm slice thickness and 0.5mm pixel. Target‐simulating wires inside the phantom were contoured and later transferred to the BAT Sxi unit (Nomos Corp., Cranberry, PA). Various thicknesses (1–8cm) of fat simulating material (SOS = 1435 m/s), manufactured by CIRS, were placed on top of the phantom to study the depth‐related alignment error. In order to demonstrate that the speed artifact is not caused by adding additional layers on top of the phantom, we repeated these measurements in an identical setup using tissue simulating material (SOS=1540 m/s) for the top layers. Result and Discussion: For the fat simulating material used in this study, we observed the magnitude of the depth‐related alignment errors resulting from this speed artifact to be 0.73 mm per cm of fat imaged‐through. The measured alignment errors caused by the speed artifact agreed with the calculated values within measurement uncertainties for the five different thicknesses of fat simulating material studied here. Conclusion: We demonstrated the depth‐related alignment error due to speed artifact when using US image guidance for radiation treatment alignment. When possible, care should be taken to avoid imaging through a thick layer of fat for larger patients in US alignments.

A standardized, comprehensive magnetic resonance imaging protocol for rapid and precise quantification of HIV‐1‐associated lipodystrophy

Although multiple methods have been proposed, there is no current gold standard for assessing HIV-1-associated lipodystrophy. HIV-1-infected participants were randomly enrolled and surveyed about changes in the abdomen, thigh, cheek and neck areas. Magnetic resonance imaging (MRI) sequences of these sites were obtained. Participants were grouped according to survey results, and the MRI measurements were compared between groups. One hundred participants were included in the study, of whom 79% reported any body fat changes. Persons reporting increased abdominal girth had higher visceral ([mean+/-standard deviation] 142+/-75 vs. 59+/-48 cm2; P<0.0001) and total abdominal adipose tissue than those reporting no change (344+/-119 vs. 201+/-95 cm2; P<0.0001). The amount of localized fat was less for persons reporting sunken cheeks and reduced diameter of the legs compared with those who noted no changes (5.9+/-3.6 vs. 9.3+/-3.8 cm2; P<0.0001, and 35+/-28 vs. 112+/-56 cm2; P<0.0001). Participants reporting increased neck girth had a thicker fat layer in the dorsocervical region compared with those reporting no change (4.0+/-1.8 vs. 2.3+/-1.4 cm; P<0.0002). MRI is a precise method for rapidly surveying body regions affected by HIV-1-associated lipodystrophy. Our proposed protocol provides a rapid, comprehensive survey of these areas, without the need to combine multiple modalities or to expose subjects to radiation.

Aging time effect on quality meat from buffaloes fed on two different diets

The aim was to investigate the effect of two different diets on buffalo meat aging. The trial was carried out on 14 male buffaloes subdivided in two groups. During the finishing period the first group was fed mainly on alfalfa hay (AH), while the second group on maize silage (MS).The animals were slaughtered at 16 months of age and at 3 hours from slaughter the longissimus thoracis muscle was removed and stored at 2+1 °C until 14 days, to evaluate the effect of aging times on meat quality. The animals fed on maize silage, because of thicker fat layer, showed slower temperature fall and faster pH fall (5.53 vs 5.56 respectively for MS vs AH on 48 hours). Shear force value was higher for the animals fed on alfalfa hay during whole aging period (from 5.78 kg to 3.32 kg for AH and from 4.70 kg to 2.63 kg for MS) and their meat showed lower lightness particularly at 48 hours from slaughter (39.0 vs 41.2) and higher percentage of oxymyoglobin. Diet affect on aging performances, particularly for tenderness and also if the MS meat showed lower shear force it appeared more degraded and not very bright.

Der Einfluß von Bauchwandzusammensetzung und Bauchwanddicke auf das Ultraschall-B-Bild

Using a tissue-mimicking phantom and a computerised sonography system an ultrasound b scan analysis was performed. The images were acquired with different fat-muscle combinations as ultrasound wave path. These are simulations of a different composition or thickness of the abdominal wall. The analysis of the ultrasound images was performed using mathematical statistical parameters for ultrasound tissue characterisation. We examined the influence of the thickness or composition of the abdominal wall on ultrasound image brightness, microtexture and macrotexture. A dependence of ultrasound image brightness and microtexture on the thickness of the fat path was observed. Muscle tissue shows only a weak influence on the microtexture of the ultrasound image. These data demonstrate that a thick fat layer leads to a darker and diffuse image. This disturbs the evaluation e.g. of the liver parenchyma by analysis of the echo structure and may lead to false diagnoses especially in adiposity.

Deep-heating characteristics of an RF capacitive heating device.

An RF capacitive heating device was constructed and its deep-heating characteristics were studied using three mini-pigs. The deep-heating ability of RF capacitive heating was found to be improved by enlarging the electrodes, driving at 8 MHz, cooling the skin under the electrodes, inserting a bolus between the body and the electrodes and considering the anatomical structure of the body. The heating characteristics obtained were as follows. When applicators were placed on both sides of the abdomen of a mini-pig, 7 mm in fat layer thickness and 23 cm in lateral chest thickness, the increase in temperature of the deep part was greater than that of the fat layer. When applicators were placed on the posterior and anterior abdomen, overheating was noted in the fat and muscle near the back. The temperature was highest in a mock tumour, made by blocking blood flow to the spleen. The bio-heat equation revealed that RF capacitive heating accompanied by surface cooling at 10 degrees C could heat the deep portion of the body to 42 degrees C without excessive heating of a 1.6 cm thick fat layer.

Structure of bursae ovaricae surrounding the ovaries of golden hamster.

The ovaries of many mammals lie within membranous sacs called bursae ovaricae. In this study, we have examined the morphology of the bursa surrounding the hamster ovary using light and electron microscopy. The bursa is composed of three layers: (1) an inner, discontinuous bursal epithelium that faces the ovary; (2) a middle layer of connective tissue that contains fibroblasts, bundles of smooth muscle cells, and blood vessels; and (3) an outer, continuous epithelium that faces the peritoneal cavity. One side of the bursa has a thin layer of connective tissue, and because the ovary may be seen through it, we refer to this region of the bursa as the "window.' Elsewhere a thick layer of fat joins the connective tissue and blocks visualization of the ovary. Tracers (Evans blue and lanthanum) applied to the peritoneal surface do not penetrate beyond the peritoneal epithelium. Tracers injected into the bursal cavity penetrate all layers of the bursa, but do not pass through the peritoneal epithelium. Therefore, the bursa prevents tracer exchange between the bursal and peritoneal cavities, but exchange does take place between the bursal cavity and blood vessels within the bursa. We suggest that bundles of smooth muscle cells within the bursa may serve to regulate fluid volume and pressure within the bursal cavity. Possible functions of the complete bursa in the hamster are discussed.

Semilateral Decubitus Breast Examination

To the Editor.— Early detection of breast neoplasms is a tantamount factor in curability. The routine physical examination is, at times, deficient. Diagnostic acuity can be increased by adding bilateral semilateral decubitus or oblique positions to the usual examination. Lesions deep within the medial aspects, upper outer quadrants, or axillary tail, especially in large breasts, may be hidden within dense parenchyma or a thick layer of fat or may sink between ribs onto intercostal muscles when examined in the usual erect and supine positions (Fig 1). By using right and left semilateral decubitus positions (Fig 2) with both of the patient's arms elevated, both breasts will fall dependently, thereby thinning the lateral aspects, upper outer quadrant, and axillary tail of the upper breasts and the medial aspect of the lower breast (Fig 3). This allows for improved detection of small lesions hidden below a thickness of fat and breast or between ribs. Even with mammography, Lundgren 1 found that 7% of breast lesions