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Introduction: Diastasis rectus abdominis (DRA) is defined as an increased distance between the left and right muscle of the m. rectus abdominis. Pregnancy-related factors are assumed to be dominant factors in the occurrence of DRA. However DRA is not only found in peri-partum women but also in men and nulliparous women with back or pelvic pain. This study provides an inventory of the incidence of DRA in subjects with chronic back and pelvic pain. If DRA is common in both men and women then other factors besides pregnancy, like impaired motor control, should be explored as cause for DRA. Material and Methods: This study was conducted with data from 849 back pain patients. Results from ultrasound assessment of the abdominal wall were combined with anamnestic data on age, gender, medical history and pregnancies (in women). Results: There was no difference in Inter Rectus Distance cranial of the umbilicus (IRD above umbilicus) between men and women. Almost half of all women and men (45% and 43%, respectively) exhibit an increased IRD above umbilicus. The incidence of an increased IRD above umbilicus is twice as high in women below 30 years, compared to men below 30 years old. This difference is not observed for men and women above 30 years old. Discussion: DRA occurs in women during pregnancy and increases with an increasing number of pregnancies. However, this condition does not affect significantly more women than men. Increased IRD above umbilicus already occurs in young men (mean age 30). Over 30 years of age, cranial of the umbilicus there is no difference in IRD between women and men. An alternative etiological mechanism is suggested., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 van Wingerden, Ronchetti and Kleinrensink.)

Background and Purpose: This work reports on the results of a survey performed on the use of computed tomography (CT) imaging for motion management, surface guidance devices, and their quality assurance (QA). Additionally, it details the collected user insights regarding professional needs in CT for radiotherapy. The purpose of the survey is to understand current practice, professional needs and future directions in the field of fan-beam CT in radiation therapy (RT)., Materials and Methods: An online institutional survey was conducted between 1-Sep-2022 and 10-Oct-2022 among medical physics experts at Belgian and Dutch radiotherapy institutions, to assess the current status, challenges, and future directions of motion management and surface image-guided radiotherapy. The survey consisted of a maximum of 143 questions, with the exact number depending on participants' responses., Results: The response rate was 66 % (31/47). Respiratory management was reported as standard practice in all but one institution; surface imaging during CT-simulation was reported in ten institutions. QA procedures are applied with varying frequencies and methodologies, primarily with commercial anatomy-like phantoms. Surface guidance users report employing commercial static and dynamic phantoms. Four main subjects are considered clinically important by the respondents: surface guidance, CT protocol optimisation, implementing gated imaging (4DCT, breath-hold), and a tattoo-less workflow., Conclusions: The survey highlights the scattered pattern of QA procedures for respiratory motion management, indicating the need for well-defined, unambiguous, and practicable guidelines. Surface guidance is considered one of the most important techniques that should be implemented in the clinical radiotherapy simulation workflow., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

Background and Purpose: To obtain an understanding of current practice, professional needs and future directions in the field of fan-beam CT in RT, a survey was conducted. This work presents the collected information regarding the use of CT imaging for dose calculation and structure delineation., Materials and Methods: An online institutional survey was distributed to medical physics experts employed at Belgian and Dutch radiotherapy institutions to assess the status, challenges, and future directions of QA practices for fan-beam CT. A maximum of 143 questions covered topics such as CT scanner availability, CT scanner specifications, QA protocols, treatment simulation workflow, and radiotherapy dose calculation. Answer forms were collected between 1-Sep-2022 and 10-Oct-2022., Results: A 66 % response rate was achieved, yielding data on a total of 58 CT scanners. For MV photon therapy, all single-energy CT scans are reconstructed in Hounsfield Units for delineation or dose calculation, and a direct- or stoichiometric method was used to convert CT numbers for dose calculation. Limited use of dual-energy CT is reported for photon (N = 3) and proton dose calculations (N = 1). For brachytherapy, most institutions adopt water-based dose calculation, while approximately 26 % of the institutions take tissue heterogeneity into account. Commissioning and regular QA include eleven tasks, which are performed by two or more professions (29/31) with varying frequencies., Conclusions: Dual usage of a planning CT limits protocol optimization for both tissue characterization and delineation. DECT has been implemented only gradually. A variation of QA testing frequencies and tests are reported., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

Introduction: Therapeutic efficacy of disease-modifying therapies (DMTs) for multiple sclerosis (MS) is often hindered by poor persistence and adherence, impacted by patient-perceived efficacy concerns, adverse effects, inconvenience, and forgetfulness. This study measured persistence, adherence, and time to switching to higher-cost therapy among patients with MS initiating teriflunomide, dimethyl fumarate, fingolimod, or diroximel fumarate treatment., Methods: This retrospective study used Symphony Health US claims data from patients with MS newly initiated on one of four oral DMTs between January and June 2020. Persistence was defined as the duration a patient continued their medication. Adherence was measured using medication possession ratio (MPR); patients with MPR ≥ 80% were considered adherent. Switching was measured by comparing proportions of patients switching and mean time to switch to one of three higher-cost therapies (ocrelizumab, natalizumab, or cladribine). Kaplan-Meier curves assessed persistence. Chi-square tests determined proportions of patients on therapy after 12 months., Results: A total of 6934 patients newly initiated on oral DMTs met study inclusion criteria (teriflunomide, n = 1968; dimethyl fumarate, n = 3409; diroximel fumarate, n = 616; fingolimod, n = 941). Patients newly initiated on teriflunomide and fingolimod had significantly higher persistence rates after 12 months (60% and 66%, respectively vs 44% dimethyl fumarate and 49% diroximel fumarate; p < 0.0001), and the highest proportion of adherent patients at 6 months (71% and 76%, vs 60% dimethyl fumarate and 58% diroximel fumarate) and 12 months (55% and 59%, vs 40% dimethyl fumarate and 44% diroximel fumarate). Mean time to switching to higher-cost therapies ranged from 247 days (diroximel fumarate to natalizumab) to 342 days (teriflunomide to ocrelizumab), with the highest rate of switching in patients on dimethyl fumarate (7%)., Conclusion: Patients newly initiated on teriflunomide and fingolimod had better real-world persistence and adherence at 6 and 12 months, and longer time to switch to higher-cost therapies, than patients on dimethyl fumarate or diroximel fumarate., (© 2022. The Author(s).)

Objective: Teriflunomide is a once-daily, oral disease-modifying therapy (DMT) for relapsing forms of multiple sclerosis (MS). We studied clinical outcomes in a real-world setting involving a population-based large cohort of unselected patients enrolled in The Danish Multiple Sclerosis Registry (DMSR) who started teriflunomide treatment between 2013-2019., Methods: This was a complete nationwide population-based cohort study with prospectively enrolled unselected cases. Demographic and disease-specific patient parameters related to treatment history, efficacy outcomes, and discontinuation and switching rates among other clinical variables were assessed at baseline and during follow-up visits., Results: A total of 3239 patients (65.4% female) started treatment with teriflunomide during the study period, 56% of whom were treatment-naïve. Compared to previously treated patients, treatment-naïve patients were older on average at disease onset, had a shorter disease duration, a lower Expanded Disability Status Scale score at teriflunomide treatment start and more frequently experienced a relapse in the 12 months prior to teriflunomide initiation. In the 3001 patients initiating teriflunomide treatment at least 12 months before the cut-off date, 72.7% were still on treatment one year after treatment start. Discontinuations in the first year were due mainly to adverse events (15.6%). Over the full follow-up period, 47.5% of patients discontinued teriflunomide treatment. Sixty-three percent of the patients treated with teriflunomide for 5 years were relapse-free, while significantly more treatment-naïve versus previously treated patients experienced a relapse during the follow-up (p<0.0001). Furthermore, 85% of the patients with available data were free of disability worsening at the end of follow-up., Conclusions: Solid efficacy and treatment persistence data consistent with other real-world studies were obtained over the treatment period. Treatment outcomes in this real-world scenario of the population-based cohort support previous findings that teriflunomide is an effective and generally well-tolerated DMT for relapsing MS patients with mild to moderate disease activity., Competing Interests: This study was funded by Sanofi. VP: has received support for scientific meetings from Merck and Sanofi Genzyme and honoraria for lecturing from Alexion. MDB: None. VS: None. PVR: has served on scientific advisory board for Biogen, Sanofi, Roche, Novartis, Merck, and Alexion, has received honoraria for lecturing from Biogen, Merck, Novartis, Roche, has received support for congress participation from Biogen, Genzyme, Roche, Merck, Novartis. ZI: has served on scientific advisory boards, received support for congress participation, received speaker honoraria, or received research support for his laboratory from Biogen, Merck, Roche, Sanofi Genzyme. MK: None. CH: has served on scientific advisory board for Biogen, Sanofi, Roche, Novartis, has received honoraria for lecturing from Biogen, Merck, Novartis, Sanofi, Genzyme, has received support for congress participation from Biogen and Roche. ZM: None. HR: None. TS: has served on scientific advisory boards, received support for congress participation, received speaker honoraria and received research support from Biogen and Novartis, and received support for congress participation by Roche. AW: has served on scientific advisory board for Merck, Biogen and Roche, has received honoraria for lecturing and publications from Sanofi Genzyme, Merck, Roche and has received support for congress participation from Biogen, Genzyme, Teva, Merck and Roche. JvW and SSG are employees of Sanofi. SB: has received support for congress participation from Biogen and Roche. FS: has served on scientific advisory boards, been on the steering committees of clinical trials, served as a consultant, received support for congress participation, received speaker honoraria, or received research support for his laboratory from Biogen, EMD Serono, Merck, Novartis, Roche, Sanofi Genzyme and Teva. MM: has served on scientific advisory board for Biogen, Sanofi, Roche, Novartis, Merck, Abbvie, Alexion has received honoraria for lecturing from Biogen, Merck, Novartis, Sanofi, Genzyme, has received research support and support for congress participation from Biogen, Genzyme, Roche, Merck, Novartis. The specific roles of these authors are articulated in the ‘author contributions’ section. With reference to PLOS ONE policies on sharing data and materials, we confirm that this does not alter our adherence to PLOS ONE policies on sharing data and materials.

This study uses a quasi-experimental research design to investigate whether a personal resources intervention combined with strengths use can increase work engagement. Following job demands-resources theory, we argue that when employees strengthen their beliefs regarding how much control they have over their environment (i.e., increase their personal resources) and use their character strengths, they will be more engaged at work. The intervention focused specifically on impacting assertiveness, self-efficacy, and resilience. We hypothesized that the intervention would increase work engagement through an increase in personal resources. Participants were all enrolled for a personal resources training and were assigned to training intervention groups (n = 54) or waiting-list control groups (n = 48). Results of multivariate analyses of variance supported our hypotheses that the intervention increased personal resources, strengths use, and work engagement. In addition, process analyses using a bootstrapping procedure showed that in the intervention group (not in the control group), the intervention had a positive impact on changes in work engagement through changes in self-efficacy and resilience. We discuss the implications of these findings for job demands-resources theory, as well as the practical implications. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Research in the field of work and organizational psychology more and more highlights the importance of employees' experience of meaningful work. Adding to this area of research, the present study among teachers examined the relationship between meaningful work and resilience and tested whether this proposed relationship is mediated by teachers' work engagement and job crafting behaviour. Data for this study was collected among a group of Dutch teachers working in a school for primary education (N = 174). To test the hypothesized relationships, we conducted a bootstrapping analysis. The outcomes revealed that work engagement and job crafting fully mediated the relationship between meaningful work and teacher's resilience. The insights provided in this study may be useful for the deliberate cultivation of teachers' resilience and may help them to stay enthusiastic in their meaningful but demanding profession. Theoretical contributions, limitations, suggestions for future research and practical implications are discussed., Competing Interests: The authors have declared that no competing interests exist.

Research in the field of work and organizational psychology increasingly highlights the importance of meaningful work. Adding to this growing body of research, this study examined the complex linkage between meaningful work and performance. More specifically, we hypothesized that meaningful work has a positive relationship with an employee's performance in several and interrelated ways, via employees' use of strengths, via work engagement, and via strengths use affecting work engagement. We conducted a structural equation modeling on a sample of 459 professionals working at a global operating organization for health technology. The results provided support for the proposed model which showed a better fit than the sequential mediation model and the direct effects model. This indicates that the meaningful work-performance relationship is predicted best by multiple pathways via employees' use of strengths and work engagement. The main theoretical, practical, and methodological implications of the results are discussed., Competing Interests: The authors have declared that no competing interests exist.

•The workflow of inspiration breath-hold SBRT for liver metastases is described.•Inspiration breath-hold in liver SBRT is feasible for 95% of the patients.•An individual margin recipe for inspiration breath-hold liver SBRT is explained.•Margin reduction of 10 mm using inspiration breath-hold compared to free breathing., (© 2018 The Authors.)

Although the role of health care professionals is known to have changed over the last years, few formal efforts have been made to examine this change through means of a scientific review. Therefore, the goal of this paper was to investigate the changing role of health care professionals in nursing homes, as well as the conditions that make this change possible. A systematic review of health care literature published in the last decade (2007-2017) was utilized to address these goals. Our findings suggest that although health care in nursing homes is shifting from task-oriented care to relation-oriented care (e.g., through an increased focus on patient dignity), various obstacles (e.g., negative self-image, work pressure, and a lack of developmental opportunities), needs (e.g., shared values, personal development, personal empowerment, team development, and demonstrating expertise), and competences (e.g., communication skills, attentiveness, negotiation skills, flexibility, teamwork, expertise, and coaching and leadership skills) still need to be addressed in order to successfully facilitate this change. As such, this paper provides various implications for health care research, health care institutions, practitioners, HR professionals and managers, and occupational health research.

The present study was designed to gain knowledge of the relationship between employees' perceived opportunities to craft, their actual job crafting behavior and, in line with JD-R theory, subsequently their work engagement and performance. Although scholars have suggested that employees' perceived opportunities to craft their job may predict their actual job crafting behavior, which may have consequences for their well-being and performance, no study has examined the relationships between these variables. We collected data among a heterogeneous group of Dutch employees ( N = 2090). Participants of the study reported their perceived opportunities to craft, job crafting behavior, work engagement and performance. Results indicated that individuals who experience a high level of opportunities to craft reported higher levels of job crafting behavior. In turn, perceived opportunities to craft and job crafting behavior related to higher levels of work engagement and subsequently performance. We discuss the implications of these findings for theory and practice.

We developed and validated a scale to measure employees' perceived opportunity to craft (POC) in two separate studies conducted in the Netherlands (total N = 2329). POC is defined as employees' perception of their opportunity to craft their job. In Study 1, the perceived opportunity to craft scale (POCS) was developed and tested for its factor structure and reliability in an explorative way. Study 2 consisted of confirmatory analyses of the factor structure and reliability of the scale as well as examination of the discriminant and criterion-related validity of the POCS. The results indicated that the scale consists of one dimension and could be reliably measured with five items. Evidence was found for the discriminant validity of the POCS. The scale also showed criterion-related validity when correlated with job crafting (+), job resources (autonomy +; opportunities for professional development +), work engagement (+), and the inactive construct cynicism (-). We discuss the implications of these findings for theory and practice.

Following bariatric surgery, body-contouring surgery is often combined with reconstruction of the musculofascial layers of the abdominal wall. Large amounts of tissue have to be retracted from the start to assist in lymph and venous drainage, and to facilitate a lower abdominal incision. During the procedure a good retractor is indispensable. The Rultract retractor system was originally developed for thoracic surgery. We have found this system, which is readily available in most centres, to be a suitable retractor in difficult post-bariatric surgery, where the patient requires abdominal wall reconstruction in combination with a dermolipectomy. It can be easily adjusted to a wide variety of desired positions without obstructing the surgeon's range of action and replaces the need for one or more assistants in the operating team.

A model of sacroiliac joint (SIJ) function postulates that SIJ shear is prevented by friction, dynamically influenced by muscle force and ligament tension. Thus, SIJ stability can be accommodated to specific loading situations. The purpose of this study was to examine, in vivo, whether muscles contribute to force closure of the SIJ. SIJ stiffness was measured using a verified method combining color Doppler imaging with induced oscillation of the ilium relative to the sacrum in six healthy women. SIJ stiffness was measured both in a relaxed situation and during isometric voluntary contractions (electromyographically recorded). The biceps femoris, gluteus maximus, erector spinae, and contralateral latissimus dorsi were included in this study. Results were statistically analyzed. The study showed that SIJ stiffness significantly increased when the individual muscles were activated. This held especially true for activation of the erector spinae, the biceps femoris and the gluteus maximus muscles. During some tests significant co-contraction of other muscles occurred. The finding that SIJ stiffness increased even with slight muscle activity supports the notion that effectiveness of load transfer from spine to legs is improved when muscle forces actively compress the SIJ, preventing shear. When joints are manually tested, the influence of muscle activation patterns must be considered, since both inter- and intra-tester reliability of the test can be affected by muscle activity. In this respect, the relation between emotional states, muscle activity and joint stiffness deserves further exploration.

The groin flap remains an excellent choice as a distant pedicled, or free microvascular flap for soft-tissue coverage of the hand because of its reliable arterial-venous pedicle and minimal donor site morbidity. Although interest has waxed and waned over the years, a number of valuable aids have been developed that have added to the success of the flap. Some of these aids, which do not yet appear in the textbooks, are briefly reviewed.

Costosternal chondrodynia (Tietze's syndrome variant) should be considered in those rare patients who present with severe breast pain several months after reconstructive breast surgery. The authors treated 25 cases, 3 of which are discussed in detail, where the origin of the pain was traced to the costosternal cartilages. The differential diagnosis and management of this hitherto undescribed problem after breast surgery are discussed.

The author suggests that an aesthetically pleasing ratio between nipple and areola diameter exists which should always be taken in consideration during nipple and areola reconstruction. In a study of 40 nipple-areola complexes of 20 healthy, nulliparous, Caucasian female volunteers with a mean age of 25.5 years, the average nipple diameter measured 28% of the areola diameter, that is, a ratio of 1:3.6. A hitherto undescribed form of macrothelia is presented in which the nipple width rather than the projection (length) is increased. A successful technique for reconstruction is described, based on the new method of assessing the aesthetic relations within the nipple-areola complex and known anatomy.

A cross-sectional study was conducted to explore the relationship between dynamic parameters of trunk muscle strength and the occurrence of low-back pain (LBP). Isodynamic strength measurements were performed among 31 male maintenance workers with spells of low-back pain in the past 12 months and 28 maintenance workers without a history of low-back pain. In general, workers with low-back pain showed a lower trunk muscle performance than the workers without low-back pain. Only the measures of torque during lateral movement differed significantly between both groups. Regression analysis revealed the importance of the nature of low-back pain for trunk muscle strength. Most parameters of trunk muscle strength were significantly decreased among workers with chronic low-back pain of a rather severe nature, showing reductions from 18% to 50%. None of the work-related risk factors for low-back pain contributed significantly to the prediction of trunk strength measures. The study suggests that isodynamic evaluation of trunk muscle strength may assist in determining objective measures for the severity of low-back pain rather than in evaluating a subject's capability of successfully coping with a specific work load.

Various joint positions of the upper extremity were used to study the tensile forces on the median nerve. To analyse the effect of embalmment, tensile forces were measured in situ in unembalmed and embalmed human bodies. A positive correlation was found between tensile force data from unembalmed and embalmed nerves. This finding justifies, for comparative studies, the use of embalmed human bodies, although the absolute tensile forces are higher. RELEVANCE: In daily activities or during certain operations positions of the upper extremity vary, hence creating tensile forces of different magnitude on peripheral nerves. Tensile forces are also applied in the diagnosis of nerve (root) lesions of the upper extremity. To analyse these tensile forces, in-situ experiments on unembalmed human bodies, though problematic, are supposed to be the most realistic approach. In this study it has been shown that in comparative studies on peripheral nerve tension, data obtained from embalmed human bodies can be used.

Study Design: The superficial and deep lamina of the posterior layer of the thoracolumbar fascia have been studied anatomically and biomechanically. In embalmed human specimens, the posterior layer has been loaded by simulating the action of various muscles. The effect has been studied using raster photography., Objectives: To study the role of the posterior layer of the thoracolumbar fascia in load transfer between spine, pelvis, legs, and arms., Summary of Background Data: It has been determined whether muscles such as the gluteus maximus, latissimus dorsi, erector muscle, and biceps femoris are functionally coupled via the thoracolumbar fascia. The caudal relations of the posterior layer of the thoracolumbar fascia have not been previously studied., Methods: Dissection was directed to the bilaminar posterior layer of the thoracolumbar fascia of 10 human specimens. The superficial and deep lamina were studied using visual inspection and raster photography. Tension to the posterior layer of the fascia was simulated by traction to various muscles and measured by studying the displacement in the posterior layer., Results: Traction to a variety of muscles caused displacement of the posterior layer. This implies that in vivo, the superficial lamina will be tensed by contraction of various muscles, such as the latissimus dorsi, gluteus maximus and erector muscle, and the deep lamina by contraction of the biceps femoris. Caudal to the level of L4 (in some specimens, L2-L3), tension in the posterior layer was transmitted to the contralateral side., Conclusions: Anatomic structures normally described as hip, pelvic, and leg muscles interact with so-called arm and spinal muscles via the thoracolumbar fascia. This allows for effective load transfer between spine, pelvis, legs, and arms--an integrated system. Specific electromyographic studies should reveal whether the gluteus maximus muscle and contralateral latissimus dorsi muscle are functionally coupled, especially during rotation of the trunk. In that case, the combined action of these muscles assists in rotating the trunk, while simultaneously stabilizing the lower lumbar spine and sacroiliac joints.

Problem creases of the face such as frontal lines and frown lines, crow's feet, deep nasolabial and perioral folds, and cervical bands may be caused by the aging process, excessive exposure to the sun, disease, or genetic disposition. The condition may become aggravated by habitual hyperkinesia of certain mimetic muscles like the frontalis, corrugators, orbicularis oculi, levatores labii superioris, zygomatici, and the platysma. The diagnosis is established clinically by electromyography and selective muscle and nerve blocks. In these cases we advocate regulation of the mimetic hyperkinesia through selective myotomy, myectomy, and neurotomy of the responsible mimetic muscles (mimetic modulation). These procedures may be performed exclusively or in combination with a blepharoplasty, rhytidectomy, or other procedure. Our experience with 60 patients over the past five years (medium = 3.5 years) is presented. Problems and complications such as paresthesia and hypesthesia, partial paresis and asymmetry, incomplete correction, and recurrences are discussed. We believe that mimetic modulation is a valuable concept in treating problem creases and thereby improves the results of the aesthetic surgery of the face.

The postures of the trunk of eight parcel sorters were measured continuously under three different working conditions, during whole shifts. The working methods used were two different sorting tables and a hydraulic lifting platform on which the carts were to be placed. The question posed by the PTT-Post occupational health service was whether the latter method proved to be the better one with respect to the load on the musculoskeletal system. This study will help them to make a well-considered decision on which working method to choose for the new distribution centre in Rotterdam. The method used for measuring the working postures and movements of the trunk is the Portable Posture Registration Set (PPRS). This method was developed at the department of Biomedical Physics and Technology of the Erasmus University Rotterdam. While using the lifting platform, the subjects stood 8-11% more erect compared to the work at the sorting tables, thereby reducing the load on the lumbar spine. For this reason the lifting platform is preferred, although sagittal flexion of the back was somewhat more. It is stressed that the way in which sorters use the lifting platform is very important.

Summary. Sacroiliac joint dysfunction is often overlooked as a possible cause of low back pain. This is due to the use of reductionistic anatomical models. From a kinematic point of view, topographic anatomical models are generally inadequate since they categorize pelvis, lower vertebral column and legs as distinct entities. This functional-anatomical study focuses on the question whether anatomical connections between the biceps femoris muscle and the sacrotuberous ligament are kinematically useful. Forces applied to the tendon of the biceps femoris muscle, simulating biceps femoris muscle force, were shown to influence sacrotuberous ligament tension. Since sacrotuberous ligament tension influences sacroiliac joint kinematics, hamstring training could influence the sacroiliac joint and thus low back kinematics. The clinical implications with respect to 'short' hamstrings, pelvic instability and walking are discussed.

Movement in eight sacroiliac joints was measured in preparations of embalmed elderly humans and compared with radiological findings. For the biomechanical part of the study the connections between sacrum and fifth lumbar vertebra were spared, as were the surrounding ligaments. The pelvis-spine preparation was fixed at the fifth lumbar vertebra. To induce movement, forces were directed at the acetabula. With digital displacement meters rotation was measured between the sacral and iliac part of the sacroiliac joint. In the sagittal plane both ventral rotation (as part of nutation) and dorsal rotation (as part of contranutation) could be demonstrated. Most sacroiliac joints were mobile, allowing a total rotation of up to 4°. Significant intraindividual differences in mobility occurred. One sacroiliac joint without mobility showed radiographically pronounced arthrosis. The impact of the findings on kinematic chain and clinical diagnosis is discussed. In the literature no data are available on the radiographic appearance of biomechanically studied sacroiliac joints. In the present study a biomechanical and radiological approach has been combined. The study emphasizes the clinical importance of intraindividual sacroiliac differences as well as the need for a thorough integration of pelvic and lumbar kinematics., (Copyright © 1992. Published by Elsevier Ltd.)

This paper shows how measurement errors in phase shifting interferometry (PSI) can be described to a high degree of accuracy in a linear approximation. System error sources considered here are light source instability, imperfect reference phase shifting, mechanical vibrations, nonlinearity of the detector, and quantization of the detector signal. The measurement inaccuracies resulting from these errors are calculated in linear approximation for several formulas commonly used for PSI. The results are presented in tables for easy calculation of the measurement error magnitudes for known system errors. In addition, this paper discusses the measurement error reduction which can be achieved by choosing an appropriate phase calculation formula.

A pilot study was carried out on 10 subjects to examine the effect that a desk with a 10 degree inclination had on their sitting posture while reading and writing. A continuous recording of the subjects head and trunk positions was made. Each subject was studied during two periods of 1.5 h on different days. The subject worked at a flat desk on the first day and at a desk with a 10 degree inclination on the second. On average, the position of the head in the sagittal plane was found to be 6 degrees more erect and the position of the trunk 7 degrees more erect when working at a desk with a 10 degree inclination than when working at a flat desk. The maximal decrease in load observed on the cervical spine was 35% and on the thoracic spine 95%. The angle between the head and the trunk did not change significantly when using an inclined desk. Differences in posture in the frontal plane were not observed in this study.

Experience with 2 patients stimulated a review of the literature on congenital absence of the vas deferens in 133 cases. Bilateral absence was more common and occurred in 80 per cent of the cases, and a caput epididymidis was said to be present in at least 88 per cent. Information concerning the epididymis was lacking in 8.9 per cent of the cases. Two probable explanations for this common clinical finding are offered. Embryologic studies have shown that the caput, unlike the rest of the epididymis, can develop from genital ridge derivatives mainly. This clinical-embryological consideration refutes the common belief that the vas deferens and epididymis as a whole are of mesonephric duct origin. A second, independent factor is the selective blood supply of the caput in some cases. In these cases the caput is preserved by a branch of the testicular artery, perforating the tunica albuginea from within outwards, instead of a branch of the spermatic artery originating from the extratesticular portion of the testicular artery.

A case of familial hypercholesterolaemia is presented. This is to the best of our knowledge the first report of such a case in a South African black. The modes of presentation and inheritance are discussed and the relevant literature is reviewed.

Ultrasound mammography is presented as a safe, simple, and reliable method of assessing prosthesis and prosthesis-related complications in the augmented breast. The ability to distinguish between silicone gel, muscle, hematoma, and fluid collections has made ultrasound mammography especially valuable in diagnosing capsular rupture, implant rupture, or periprosthetic hematoma in subpectoral breast augmentations. Examples are given and discussed.

The binding and catabolism of low-density lipoprotein (LDL) was measured in cultured skin fibroblasts and Epstein-Barr virus-transformed lymphoblastoid cells from a South African black man. On the basis of LDL receptor activity, the patient was classified as a familial hypercholesterolaemic homozygote of the LDL receptor-defective type.

Although malignant fibrous histiocytoma (MFH) is thought to be the most common soft tissue tumor of late adult life, it is extremely uncommon in the parotid gland. A case of MFH in the parotid is reported, associated with polycythemia, which remitted following surgical extirpation of the tumor.