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Study Design: Prospective case series., Objectives: To investigate changes in abdominal muscle thickness with ultrasound imaging, after spinal manipulative therapy (SMT), in a subgroup of patients with low back pain (LBP) who meet a proposed clinical prediction rule for lumbar stabilization exercise (LSE)., Background: The characteristics of a subgroup of patients with LBP who respond clinically to LSE has been proposed. Although the pathoanatomical characteristics of this subgroup have not been determined, clinicians often assume that this type of LBP is related, in part, to neuromuscular deficits of the lateral abdominal muscles. Recent evidence suggests that SMT may facilitate abdominal muscle activity and, therefore, enhance exercises targeting these deficits., Methods: Nineteen patients (mean age ± SD, 32.5 ± 7.8 years; 11 female) with LBP, who met the criteria for LSE, underwent ultrasound imaging of the transversus abdominis (TrA) and internal oblique (IO) muscles before, immediately after, and 3 to 4 days after lumbopelvic SMT. Measurements of resting thickness, contracted thickness during the abdominal drawing-in maneuver, and percent thickness change from rest to contraction of the TrA and IO muscles were analyzed with repeated-measures analysis of variance. Numeric pain rating scale and Oswestry Disability Index data were also collected., Results: No significant differences in resting, contracted, or percent thickness change in the TrA or IO were found over the 3 time periods. There were statistically significant reductions in numeric pain rating scale and Oswestry Disability Index scores, but mean differences failed to meet the minimal clinically important difference., Conclusion: The results provide preliminary evidence that TrA and IO muscle resting and contracted thicknesses do not change post-SMT in patients with LBP in the LSE subgroup. In addition, while reductions in pain and disability were noted, they were not clinically meaningful.

Fresh pork bellies (n=24) were cut into 15 sections to measure the intra-belly variation in compositional and mechanical firmness characteristics. Length and width of each belly was measured before the belly was divided into 3 rows (D = dorsal; C = central; and V = ventral) and 5 columns (labeled 1, 2, 3, 4, and 5 from cranial to caudal), resulting in 15 belly sections of equal dimensions. The belly section with the greatest compression value was D-1, whereas the lowest compression value was found in the V-4 section (column×row, P<0.001). Conversely, the greatest and least puncture values were observed in the C-2 and V-5 locations, respectively (column×row, P=0.016). The D-3 section had the lowest proportion of lean and the greatest proportion of fat, but the greatest lean and lowest fat percentages were found in the V-1 and C-4 sections, respectively (column×row, P<0.001). The greatest proportions of saturated fatty acids (SFA) were found in the V-4 and V-5, and the lowest proportions of SFA were in D-1 (column×row, P<0.001). Moreover, C-4 and V-1 had the greatest percentages of monounsaturated fatty acids (MUFA), whereas the lowest MUFA content was observed in D-1, D-2, and D-3 (column×row, P<0.001). The D row (columns 1, 2, 3, and 5) also had the greatest proportion of polyunsaturated fatty acids (PUFA), but the lowest proportions of PUFA were located in C-4, V-4, and V-5 (column×row, P<0.001). Consequently, the iodine value was greatest in D-1 and lowest in V-4, V-5, and C-5 (column×row, P<0.001). It is apparent from these results that there is an obvious fatty acid composition gradient within bellies, which results in considerable intra-belly variation in composition and firmness., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Study Design: A prospective longitudinal study., Background: Diastasis recti abdominis (DRA) is defined as an increase in the inter-recti distance (IRD), or width of the linea alba. It is a common occurrence in women postpartum. Little information exists on the short- and long-term recovery of IRD and the relationship between changes in IRD and the functional performance of the abdominal muscles., Objectives: To investigate the natural recovery of IRD and abdominal muscle strength and endurance in women between 7 weeks and 6 months postpartum, and to examine the relationship between IRD and abdominal muscle function., Methods: Forty postpartum (25-37 years of age) and 20 age-matched, nulliparous females participated. IRD was measured at 4 locations (upper and lower margin of the umbilical ring, and 2.5 cm above and below the umbilical ring) with a 7.5-MHz linear ultrasound transducer. Trunk flexion and rotation strength and endurance were measured with manual muscle testing and curl-ups. Evaluation was conducted at 4 to 8 weeks and 6 to 8 months after childbirth in postpartum women, and only once for the nulliparous female controls., Results: During follow-up, the IRD at 2.5 cm above the umbilical ring and at the upper margin of the umbilical ring decreased (P = .013 and P = .002, respectively). The strength and static endurance of the abdominal muscles improved over time (P<.05). A negative correlation between IRD and abdominal muscle function at 7 weeks and 6 months postpartum was found (r = 0.34 to 0.51; P<.05, except for trunk flexion strength at 6 months postpartum [P = .064]). In addition, IRD changes between 7 weeks and 6 months postpartum were correlated with improvement in trunk flexion strength (Spearman rho = 0.38, P = .040). At 6 months after childbirth, postpartum women had greater mean ? SD IRDs at all 4 locations (from cranial to caudal: 1.80 ± 0.72, 2.13 ± 0.65, 1.81 ± 0.62, and 1.16 ± 0.58 cm) than those of nulliparous females (0.85 ± 0.26, 0.99 ± 0.31, 0.65 ± 0.23, and 0.43 ± 0.17 cm) (all P<.001). All abdominal strength and endurance measurements were less than those of nulliparous females (all P<.001)., Conclusions: The IRD and abdominal muscle function of postpartum women improved but had not returned to normal values at 6 months after childbirth. Future research is essential to explore the need for intervention and, if needed, the effectiveness of specific intervention to reduce the size of IRD in postpartum women.

Background: Recently, ultrasound-guided transversus abdominis plane blockade for abdominal wall analgesia has been described, and it involves injection of local anesthetic into the transversus abdominis plane. The posterior approach involves injection of local anesthetic in the lateral abdominal wall between the costal margin and the iliac crest and is suitable for postoperative analgesia after surgery below the umbilicus. The subcostal approach is suitable after abdominal surgery in the periumbilical region. The subcostal block can be modified, and the needle can be introduced along the oblique subcostal line from the xyphoid process toward the anterior part of the iliac crest., Objective: The purpose of this brief technical report was to describe in detail the anatomy and the technique of continuous oblique subcostal blockade. The goal of this approach was to produce a wider sensory blockade suitable for analgesia after surgery both superior and inferior to the umbilicus., Conclusions: A catheter can be placed along the oblique subcostal line in the transversus abdominis plane for continuous infusion of local anesthetic. Multimodal analgesia and intravenous opioid are used in addition because visceral pain is not blocked. Continuous oblique subcostal transversus abdominis plane block is a new technique and requires both a detailed knowledge of sonographic anatomy and technical skill for it to be successful.

The abdominal wall is a composite of muscles that are important for the mechanical stability of the spine and pelvis. Tremendous clinical attention is given to these muscles, yet little is known about how they function in isolation or how they interact with one another. Given the morphological, vascular, and innervation complexities associated with these muscles and their proximity to the internal organs, an appropriate animal model is important for understanding their physiological and mechanical significance during function. To determine the extent to which the rat abdominal wall resembles that of human, 10 adult male Sprague-Dawley rats were killed and formalin-fixed for architectural and morphological analyses of the four abdominal wall muscles (rectus abdominis, external oblique, internal oblique, and transversus abdominis). Physiological cross-sectional areas and optimal fascicle lengths demonstrated a pattern that was similar to human abdominal wall muscles. In addition, sarcomere lengths measured in the neutral spine posture were similar to human in their relation to optimal sarcomere length. These data indicate that the force-generating and length change capabilities of these muscles, relative to one another, are similar in rat and human. Finally, the fiber lines of action of each abdominal muscle were similar to human over most of the abdominal wall. The main exception was in the lower abdominal region (inferior to the pelvic crest), where the external oblique becomes aponeurotic in human but continues as muscle fibers into its pelvic insertion in the rat. We conclude that, based on the morphology and architecture of the abdominal wall muscles, the adult male Sprague-Dawley rat is a good candidate for a model representation of human, particularly in the middle and upper abdominal wall regions.

Study Design: A case report and literature review., Background: Optimizing clinical outcomes following lumbar disc surgery is a research priority; however, relatively little attention has been paid to the postoperative management of this population. The transversus abdominis and lumbar multifidus (LM) muscles appear to play a unique role in lumbar spine stability, and may relate to clinical outcome following lumbar disc surgery. The purpose of this case report was to describe the preoperative LM morphology, clinical outcome, and change in transversus abdominis and LM muscle activation in a patient following lumbar disc surgery and motor control exercise initiated in the early postoperative period., Case Description: A 29-year-old female underwent an 8-week postoperative rehabilitation program emphasizing motor control exercises to restore trunk muscle function 10 days following lumbar disc surgery., Outcomes: The patient experienced clinically important improvements in pain and disability following the postoperative rehabilitation program. Substantial improvements in muscle activation were observed of the transversus abdominis and the LM at the L4-5 level. Minimal change in LM activation and a higher proportion of intramuscular fat was observed at the L5-S1 level., Discussion: This case report represents limited evidence regarding the feasibility of instituting a rehabilitation program in the early postoperative period following lumbar disc surgery. Improvements in clinical status and muscle function were observed, and a differential change in muscle activation between the L4-5 and L5-S1 levels was noted. The literature regarding rehabilitation following lumbar disc surgery, as well as the neuromuscular changes observed in this population, was reviewed. Additionally, a novel method of examining LM morphology was described and suggestions were made for directions of future research., Level of Evidence: Therapy, level 4.

Objective: In this study, asymmetry relative to the preferred kicking leg was determined if it exists for the psoas and quadratus lumborum muscles among elite Australian Football League (AFL) players., Design: AFL players were assessed at three time points from 2005 to 2007 (start of preseason, end of season and end of preseason training). MRI was used to determine the cross-sectional areas (CSAs) of the psoas and quadratus lumborum muscles at the L4-L5 vertebral level (psoas) and the L3-L4 vertebral level (quadratus lumborum)., Setting: MRI was performed in a hospital setting., Participants: 54 professional AFL players were eligible to participate in this study. The number of subjects at each of the three time points was 36 for time 1 (T1 Nov 2005), 31 for time 2 (T2 Aug 2006) and 43 for time 3 (T3 Feb Mar 2007)., Risk Factors: The repeated measures factor in the analyses was "asymmetry", defined as "ipsilateral" or "contralateral" to preferred kicking leg. Number of injuries (coded as 0, 1, 2 or more) was also included as a risk factor., Main Outcome Measurements: The dependent variables were the CSAs of the psoas and quadratus lumborum muscles., Results: At all three time points, the CSA of the psoas muscle was significantly greater ipsilateral to the kicking leg, while the CSA of the quadratus lumborum muscle was significantly greater on the side contralateral to the kicking leg. Asymmetry in muscle size was not related to number of injuries., Conclusions: Asymmetry of the psoas and the quadratus lumborum muscles exists in elite AFL players.

Objectives: To compare the effect of the abdominal draw-in manoeuvre with the abdominal draw-in manoeuvre in combination with ankle dorsiflexion on changes in muscle thickness and associated muscle activity in abdominal muscles., Design: A preliminary, randomised, controlled study., Setting: University laboratory., Participants: Forty healthy adults (18 males, 22 females) were allocated at random to the experimental group [mean age (SD) 24 (1.6) years, n=20] or the control group [mean age (SD) 24 (1.9) years, n=20]. The experimental group performed the abdominal draw-in manoeuvre in combination with ankle dorsiflexion, and the control group performed the abdominal draw-in manoeuvre alone, five times a day., Main Outcome Measures: Ultrasonography and electromyography were used to determine the intervention-related changes in muscle activity and the thickness of abdominal muscles during the abdominal draw-in manoeuvre or the abdominal draw-in manoeuvre in combination with ankle dorsiflexion., Results: A significant difference was found in the thickness of the transverse abdominal muscle between the groups [mean difference 0.24 cm, 95% confidence interval (CI) 0.08 to 0.40, P=0.005. On electromyography, a significant difference was demonstrated in the amplitude of the transverse abdominal muscle contraction between the two techniques in the experimental group (mean difference 68.76 mV, 95% CI 53.16 to 84.36, P=0.000. The intra-class correlation coefficient (ICC(2,1)) showed excellent test-retest reliability of ultrasound measurement of the abdominal muscles: 0.96 (95% CI 0.85 to 0.99) for the transverse abdominal muscle, 0.87 (95% CI 0.62 to 0.98) for the internal oblique muscle and 0.77 (95% CI 0.44 to 0.96) for the external oblique muscle., Conclusions: This is the first study to demonstrate the additive effect of ankle dorsiflexion on deep core muscle thickness and activity, thus contributing to existing knowledge about therapeutic exercise for the effective management of low back pain., (Copyright 2009 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.)

Mammals have four hypaxial muscle layers that wrap around the abdomen between the pelvis, ribcage, and spine. However, the marsupials have epipubic bones extending anteriorly into the ventral hypaxial layers with two additional muscles extending to the ventral midline and femur. Comparisons of South American marsupials to basal eutherians have shown that all of the abdominal hypaxials are active bilaterally in resting ventilation. However, during locomotion marsupials employ an asymmetrical pattern of activity as the hypaxial muscles form a crosscouplet linkage that uses the epipubic bone as a lever to provide long-axis support of the body between diagonal limb couplets during each step. In basal eutherians, this system shifts off the femur and epipubic bones (which are lost) resulting in a shoulder to pelvis linkage associated with shifts in both the positions and activity patterns of the pectineus and rectus abdominis muscles during locomotion. In this study, we present data on hypaxial function in two species (Pseudocheirus peregrinus and Trichosurus vulpecula) representing the two major radiations of possums in Australia: the Pseudocheiridae (within the Petauroidea) and the Phalangeridae. Patterns of gait, motor activity, and morphology in these two Australian species were compared with previous work to examine the generality of 1) the crosscouplet lever system as the basal condition for the Marsupialia and 2) several traits hypothesized to be common to all mammals (hypaxial tonus during resting ventilation, ventilation to step synchrony during locomotion, and bilateral transversus abdominis activity during locomotor expiration). Our results validate the presence of the crosscouplet pattern and basic epipubic bone lever system in Australian possums and confirm the generality of basal mammalian patterns. However, several novelties discovered in Trichosurus, reveal that it exhibits an evolutionary transition to intermediate eutherian-like morphological and motor patterns paralleling many other unique features of this species., ((c) 2009 Wiley-Liss, Inc.)

Today non-traumatic low back pain (LBP) is a social disease being attributed to weakening the function of abdominal and back muscles. Condition of deep muscles, inaccessible to non-invasive examinations, can be assessed by means of magnetic resonance imaging (MRI). The method allows for the assessment of cross-sections, muscle girths, as well as their intensity (brightness). The aim of the investigations was to determine the opportunities to employ MRI technique for assessing the geometry of muscles which stabilize spinal column. The study covered 4 women without LBP symptoms. The cross-sectional area, thickness and brightness of abdominal and back muscles were measured at the level of L3-L4. Measurement of geometrical parameters in the positions studied was aimed at setting such measurement conditions that would force higher isometric contraction in the muscles examined. As a result of measurements it can be inferred that other conditions of the experiment affect neither an increase in cross-sectional surface area nor the thickness of the muscles examined. The differences observed in geometrical parameters of the muscles testify to different coordination of muscle activation in the positions studied, both in young and older subjects, and to the purposefulness of continuing this type of measurements.

Study Design: Single-blinded quasi-experimental study., Objective: To investigate the ability of elite football players with and without low back pain (LBP) to voluntarily draw-in the abdominal wall., Background: While there has been considerable debate regarding the contribution of the transversus abdominis (TrA) muscle to control the lumbar spine and pelvis, there is evidence that retraining motor control of the deep trunk muscles is commensurate with decreases in LBP. Magnetic resonance imaging (MRI) has been used to assess the TrA muscle during the draw-in maneuver, with the contraction of the TrA muscle reducing the circumference of the trunk. Impairments in performance of the draw-in maneuver have been shown in people with LBP., Methods: Forty-three elite players from a team in the Australian Football League were allocated to 3 groups: those with "no LBP," "a history of LBP but no current LBP," or "current LBP." MRI was used to image the cross-sectional area (CSA) of the trunk at the level of the L3-4 disc at the start and end of the draw-in maneuver., Results: There was a significant decrease in the CSA of the trunk with the performance of the draw-in maneuver (P<.001). Subjects in the "no LBP" group were better able to "draw-in" the abdominal wall than subjects with current LBP (P = .015)., Conclusions: This study provides evidence of an altered ability to draw-in the abdominal wall in footballers with current LBP. Retraining contraction of the TrA muscle may constitute one part of an exercise-therapy approach for athletes with current LBP.

Aberrant migration of a ventriculoperitoneal shunt catheter is an infrequent complication and the mechanism is unclear. We report three cases of subcutaneous migration of the distal catheter. The relationship between thick abdominal fat and catheter migration was suggested in all three cases. Abdominal radiography showed that the subcutaneous fat pad had slid down in the standing position, pulling the catheter out of the peritoneal cavity. We suggest the following mechanisms: Changing from the supine position to the standing position caused subcutaneous fat pad to slide down, the shifted fat pad pulled out the catheter from the peritoneal cavity, and anchoring prevents the catheter returning into the peritoneal cavity. Subcutaneous fat pad shift might act as a "windlass," resulting in coiling of the catheter in the subcutaneous tissue. During daily life, the peritoneal catheter was pulled out repeatedly and finally was coiled within the subcutaneous fat tissue. Placement of the catheter between the subcutaneous fat pad and the abdominal muscle wall will help to avoid this rare complication. This preventive measure is especially recommended for obese patients with a high risk of subcutaneous migration of the peritoneal catheter.

Background: In mesh implantations, there needs to be a balance between mass and the size of the meshes. However, the mesh size should allow for adequate prevention of hernia recurrence by sufficient coverage of the entire myopectineal orifice (MPO)., Aim and Objective: The aim was to determine the MPO dimensions and several pelvic parameters., Methods: Thirty-two inguinal regions were assessed in 16 embalmed cadavers., Results: The MPO averaged 7.8 cm (+/-3.0) in width and 6.5 cm (+/-1.9) in height. The weak inguinal area cranially to the inguinal ligament was 4.5 cm (+/-1.7) high. We found significant gender differences: MPOs in males showed the same width and height (7.6 x 7.6 cm), whereas in females, the MPO width was greater than its height (8.1 x 5.3 cm). Noticeable correlations of the MPO parameters to constitutional parameters were found for body size versus the height of the MPO (r = 0.5005) and interspinous distance versus the height of the MPO (r = 0.7653)., Conclusions: A mesh measuring 10 x 8 cm is suitable for both genders: in females, it will cover the whole MPO, including the infraligamental part, whereas in males, the weak inguinal area is preferentially covered.

The role of transversus abdominis (TrA) on spinal stability may be important in low back pain (LBP). To date, there have not been any investigations into the influence of lumbo-pelvic neutral posture on TrA activity. The present study therefore examines whether posture influences TrA thickness. A normative within-subjects single-group study was carried out. Twenty healthy adults were recruited and taught five postures: (1) supine lying; (2) erect sitting (lumbo-pelvic neutral); (3) slouched sitting; (4) erect standing (lumbo-pelvic neutral); (5) sway-back standing. In each position, TrA thickness was measured (as an indirect measure of muscle activity) using ultrasound. In erect standing, TrA (mean TrA thickness: 4.63+/-1.35 mm) was significantly thicker than in sway-back standing (mean TrA thickness: 3.32+/-0.95 mm) (p=00001). Similarly, in erect sitting TrA (mean thickness=4.30 mm+/-1.58 mm) was found to be significantly thicker than in slouched sitting (mean thickness=3.46 mm+/-1.13 mm) (p=0002). In conclusion, lumbo-pelvic neutral postures may have a positive influence on spinal stability compared to equivalent poor postures (slouched sitting and sway-back standing) through the recruitment of TrA. Therefore, posture may be important for rehabilitation in patients with LBP.

The function of the linea alba is to maintain the abdominal muscles at a certain proximity to each other. In the case of long-lasting increased intra-abdominal pressure, the linea alba widens. Yet, as the existence of the linea a priori implicates a physiological distance between the two rectus muscles, the question arises as to what the normal width of the linea alba is. To evaluate the normal width of the linea alba, we examined 150 nulliparous women between 20 and 45 years of age with a body mass index < 30 kg m(-2) by ultrasound at three reference points: the origin at the xiphoid and 3 cm above and 2 cm below the umbilicus. The examination revealed a broad range of widths at the three reference points. The linea was widest at 3 cm above the umbilicus (-35 mm), followed by the reference point 2 cm below the umbilicus (-31 mm) and the origin at the xiphoid (-31 mm). The mean width was 7 +/- 5 mm at the xiphoid and 13 +/- 7 mm above and 8 +/- 6 mm below the umbilicus. For the definition of the normal width of the linea, the 10th and 90th percentiles were taken. The linea alba can be considered "normal" up to a width of 15 mm at the xiphoid, up to 22 mm at the reference point 3 cm above the umbilicus and up to 16 mm at the reference point 2 cm below the umbilicus in nulliparous women.

Background: The transversus abdominis plane (TAP) block is a new technique for providing analgesia to the anterior abdominal wall. Most previous studies have used the lumbar triangle of Petit as a landmark for the block. In this cadaveric study, we determined the exact position and size of the lumbar triangle of Petit and identified the nerves affected by the TAP block., Methods: The position of the lumbar triangle of Petit was assessed unilaterally in 26 cadaveric specimens relative to reliably palpable surface landmarks. In addition, a series of dissections were performed to explore the course of the nerves blocked by the TAP., Results: The mean distance from the midaxillary line along the iliac crest to the center of the base of the lumbar triangle of Petit at the level of the subcutaneous tissue and over the skin surface was 6.9 cm (range, 4.5-9.2 cm) and 9.3 cm (range, 4-15.1 cm), respectively. The center of the lumbar triangle of Petit was 1.4 cm above the iliac crest. The depth of the TAP at the lumbar triangle of Petit position was 0.5-4 cm and at the midaxillary line it was 0.5-2 cm. The average size of the lumbar triangle of Petit was 2.3 cm x 3.3 cm x 2.2 cm, with an average area of 3.63 +/- 1.93 cm2. The three cadaveric specimens we explored showed the nerves blocked by TAP passed lateral to the triangle. An incidental finding was that in 66% of specimens the lumbar triangle of Petit contained small branches of the subcostal artery., Conclusions: The lumbar triangles of Petit found in the specimens in this study were more posterior than the literature suggests. The position of the lumbar triangle of Petit varies largely and the size is relatively small. The relevant nerves to be blocked had not entered the TAP in the specimens in this study at the point of the lumbar triangle of Petit. At the midaxillary line, however, all the nerves were in the TAP.

The muscular architecture of Halobiotus crispae (Eutardigrada: Hypsibiidae) was examined by means of fluorescent-coupled phalloidin in combination with confocal laser scanning microscopy and computer-aided three-dimensional reconstruction, in addition to light microscopy (Nomarski), scanning electron microscopy, and transmission electron microscopy (TEM). The somatic musculature of H. crispae is composed of structurally independent muscle fibers, which can be divided into a dorsal, ventral, dorsoventral, and a lateral musculature. Moreover, a distinct leg musculature is found. The number and arrangement of muscles differ in each leg. Noticeably, the fourth leg contains much fewer muscles when compared with the other legs. Buccopharyngeal musculature (myoepithelial muscles), intestinal musculature, and cloacal musculature comprise the animal's visceral musculature. TEM of stylet and leg musculature revealed ultrastructural similarities between these two muscle groups. Furthermore, microtubules are found in the epidermal cells of both leg and stylet muscle attachments. This would indicate that the stylet and stylet glands are homologues to the claw and claw glands, respectively. When comparing with previously published data on both heterotardigrade and eutardigrade species, it becomes obvious that eutardigrades possess very similar numbers and arrangement of muscles, yet differ in a number of significant details of their myoanatomy. This study establishes a morphological framework for the use of muscular architecture in elucidating tardigrade phylogeny., ((c) 2009 Wiley-Liss, Inc.)

Background: Rehabilitative ultrasound imaging (RUSI) measures of abdominal wall muscles are used to indirectly measure muscle activity. These measures are used to identify suitable patients and to monitor progress of motor control exercise treatment of people with low back pain., Purpose: The purpose of this study was to systematically review reproducibility studies of RUSI for measuring thickness of abdominal wall muscles., Data Sources: Eligible studies were identified via searches of MEDLINE, EMBASE, and CINAHL. The authors also searched personal files and tracked references of the retrieved studies via the Web of Science Index., Study Selection: Studies involving any type of reliability and or agreement of any type of ultrasound measurements (B or M mode) for any of the abdominal wall muscles were selected., Data Extraction: Two independent reviewers extracted data and assessed methodological quality., Data Synthesis: Due to heterogeneity of the studies' designs, pooling the data for a meta-analysis was not possible. Twenty-one studies were included, and these studies were typically of low quality and studied subjects who were healthy rather than people seeking care for low back pain. The studies reported good to excellent reliability for single measures of thickness and poor to good reliability for measures of thickness change (reflecting the muscle activity). Interestingly, no studies checked reliability of measures of the difference in thickness changes over time (representing improvement or deterioration in muscle activity)., Conclusions: The current evidence of the reproducibility of RUSI for measuring abdominal muscle activity is based mainly on studies with suboptimal designs and the study of people who were healthy. The critical question of whether RUSI provides reliable measures of improvement in abdominal muscle activity remains to be evaluated.

Study Design: In vivo measurements of low back flexion posture and muscle activity before, during, and after static flexion., Objective: To identify the occurrence of creep and muscle fatigue development in the low back during static upper body deep flexion that resembled an above ground work posture., Summary of Background Data: Static lumbar flexion has been related to the development of low back disorders, and its injury mechanism has been focused on the changes in passive spinal tissues. Potential influences of muscle fatigue of extensor muscles have not been explored., Methods: A total of 20 asymptomatic subjects performed submaximal isometric trunk extension exertions and an isokinetic trunk flexion before and immediately after 5-minute static flexion while the trunk sagittal flexion angle and the myoelectric activities (electromyography [EMG]) of back extensor muscles were recorded simultaneously. Changes in the flexion-relaxation onset angle, maximum flexion angle, muscle activity level, and the median power frequency of EMG associated with the static flexion were evaluated., Results: Flexion-relaxation onset angle in isokinetic flexion and EMG amplitude of isometric extension were significantly greater after static flexion, indicating creep of spinal tissues in static flexion. Median power frequency of lumbar erector spinae EMG during isometric extension was significantly lower after static flexion, suggesting the development of muscle fatigue. Consistent but low level of EMG was observed together with sporadic muscle spasms during the static flexion period., Conclusion: Fatigue of low back extensor muscles may occur in static flexion due to prolonged passive stretching of the muscles. Low back extensor muscles are required to generate more active forces in weight holding or lifting after static flexion to compensate for the reduced contribution of creep deformed passive tissues in maintaining spinal stability and the posture. The degraded force generating capacity of the fatigued muscles can be a significant risk factor for low back pain.

All tetrapods have the same four basic abdominal hypaxial muscle layers that wrap around the abdomen between the pelvis, ribcage, and spine. However, the marsupials and our immediate mammalian ancestors have epipubic bones extending anteriorly into the ventral hypaxial layers with two additional muscles connecting them to the ventral midline and femur. Studies of two marsupials have shown that all of the abdominal hypaxials play a part bilaterally in resting ventilation and during locomotion there is an asymmetrical pattern of activity as the hypaxial muscles form a cross-couplet linkage that uses the epipubic bone as a lever to provide long-axis support of the body between diagonal limb couplets during each step. The cross-couplet epipubic lever system defines the earliest mammals and is lost in placental mammals. To expand our understanding of the evolution of mammalian abdominal muscle function and loco-ventilatory integration we tested the generality of the cross-couplet system in marsupials and conducted the first formal studies of hypaxial abdominal motor patterns in generalized placental mammals focusing on a representative rodent and insectivore. These new data reveal 1) that continuous abdominal muscle tonus during resting ventilation and a 1:1 breath to step cycle during locomotion appear to be the basal condition for mammals, 2) that the loss of epipubic bones in eutherians is associated with a shift from the cross-couplet dominated motor pattern of marsupials to a shoulder-to-pelvis system with unilateral activation of abdominal muscles during locomotion and 3) that hypaxial function in generalized eutherians is more similar to marsupials than cursorial mammals., ((c) 2009 Wiley-Liss, Inc.)

Introduction: Abdominal wall closure management has become an important challenge during recipient candidate selection, at the time of donor to recipient matching and during the planning of the surgical procedure for intestinal or multiorgan transplantation. Different strategies have been proposed to overcome the lack of abdominal domain: to reduce the graft size or to increase the abdominal domain. Based on the recent concept of using an acellular dermis matrix (Alloderm) and the availability of abdominal wall tissues from the same organ donor, we conceived the idea of using the fascia of the rectus muscle (FoRM) as a nonvascularized tissue allograft., Materials and Methods: This is a retrospective report of a series of 16 recipients of FoRM as part of a liver, intestinal, or multiorgan transplant procedure performed between October 2004 and May 2008 at three different transplant centers., Results: Of the 16 recipients of FoRM, all but one case was performed during their transplantation (four multivisceral, two modified multivisceral, three isolated intestine, and two livers). Five patients underwent a retransplant surgery (two livers, two multivisceral, and one isolated intestine). Abdominal wall infection was present in 7 of 16 cases. Nine patients are still alive. No deaths were related to wound infection. Long-term survival showed complete wound healing and only one ventral hernia., Discussion: The use of a nonvascularized FoRM is a novel and simple surgical option to resolve complex abdominal wall defects in liver/intestinal/multivisceral transplant recipients when it can be covered with the recipient skin.

Background: The management of incisional hernias outside the midline remains a challenging procedure. Evidence-based data and even any kind of guidelines for dealing with this problem are still lacking. The aim of the study was to elucidate this field of hernia surgery and give some guidelines for retromuscular sublay mesh repair outside the midline., Materials and Methods: Fresh-frozen corpses were used to perform anatomical studies. During all the investigations the main target was to find the layer which can maintain the maximum overlap of healthy tissue with the implanted mesh material. Afterwards the findings were evaluated during clinical situations, using photo-documentation and drawings., Results: The layer between the external oblique muscle and the internal oblique muscle is the ideal place to position the mesh with adequate overlap. Even for subcostal hernias, this layer offers adequate mesh overlap behind the ribs. For lumbar hernias the same plane of dissection is usually useful. Only if the defect is situated close to the bone might preperitoneal dissection and mesh placement be necessary., Conclusion: The repair of lateral hernias must follow the same principles as median sublay repair. With sufficient knowledge of the anatomical layers of the abdominal wall, adequate mesh overlap can be achieved for any kind of lateral hernia. Therefore the retromuscular sublay repair can be regarded as the standard procedure for all types of hernia outside the midline.

Background: We report on a patient in whom a subfascially implanted pump for the intrathecal delivery of baclofen spontaneously migrated into the peritoneal cavity., Case Description: A 54-year-old male patient presented with a refilling problem of a drug pump that had been implanted 16 months earlier subfascially through a right-sided incision 10 cm below the costal margin. Because we were unable to refill the pump even under fluoroscopy, we presumed a backward turning of the pump. At exploration, we found that the deeper part of the pocket had spontaneously eroded and had caused the migration of the pump into the peritoneal cavity. The peritoneum and the abdominal wall were closed and the pump was placed in a subcutaneous pouch. We suppose that the migration of the pump was due to its particular implantation site with the lower extent of the device at or below the level of the linea semilunaris. Below this line, the aponeuroses of all 3 lateral abdominal muscles pass in front of the rectus muscle, leaving only the transversal fascia underneath the rectus, which is not a solid layer. Not considering this anatomical detail may facilitate the inward migration of implanted material., Conclusion: When creating a pocket for subfascial implantation, a high subcostal incision should be used so that the lower extent of the pocket will still be above the level of the linea semilunaris, hence ensuring a strong fascial layer between the pump and the peritoneum.

Objective: To evaluate the risk of vascular injury during transobturator approach of cystocele repair., Design: Dissection of the obturator area by perineal approach was performed after placement of mesh needles used for cystocele mesh repair., Setting: Surgery school of Paris., Population or Sample: Twenty obturator regions in ten fresh female cadavers., Methods: Transperineal dissection of the obturator area was conducted in ten fresh female anatomic subjects after inserting anterior Prolift needles., Main Outcome Measures: The vascular anatomy of the obturator region was mapped. Distances between needles and vascular structures of the obturator area were measured three times and averaged for each side., Results: The anterior cannula-equipped needle perforated the gracilis and the adductor brevis muscles. The mean (SD) distance to the anterior obturator vessels was 21.2 (1.6) mm on the right side and 20.4 (1.5) mm on the left. The posterior needle perforated the adductor magnus. Its distance to the posterior division of the obturator vessels was 1.8 (1.0) mm on the right side and 1.1 (0.9) mm on the left., Conclusions: During mesh cystocele repair by transobturator approach, the posterior obturator vessels division seems at risk of injury during the posterior needle insertion.

The anatomy of the anterolateral abdominal wall is mainly of interest to medical students early in their studies. Clinically, it is mostly relevant to surgeons who are performing laparotomies and repairing or preventing hernias. The author's life-long experience suggests that some of the lesser-known details of the anatomy of the abdominal wall have been neglected resulting in some suboptimal results. This manuscript highlights some of these details which, hopefully, will lead to improved outcomes for patients., ((c) 2009 Wiley-Liss, Inc.)

Study Design: In situ testing of the rat abdominal wall., Objective: To test the ability of muscularly generated force and stiffness to be transmitted between the layers of the abdominal wall., Summary of Background Data: The abdominal wall is comprised of 3 obliquely oriented sheet-like muscles bound together through a connective tissue network. This anatomic arrangement would seem ideal to facilitate myofascial force transmission, which if present would indicate shear connections between the muscle layers that could have important mechanical consequences., Methods: In 10 Sprague-Dawley rats, the 3 layers of the abdominal wall were isolated together and attached to a servomotor force/displacement system. The abdominal wall was stimulated via electrodes over the surface of the transverse abdominis, and measures of force and stiffness were obtained. The aponeurosis attaching the transverse abdominis to the rectus sheath was then cut and the wall was restimulated and the same measures were again obtained., Results: Active force and stiffness were both reduced in the cut aponeurosis state. These drops were much lower (10.6% and 10.7%, respectively) than would be expected if the transverse abdominis were completely removed. Furthermore, a control group (5 rats), in which the aponeurosis was not cut, but a similar amount of time to that necessary to perform the aponeurosis surgery was allowed to elapse, showed reductions in active force and stiffness (7.9 and 8.2, respectively) nearing that seen in the cut state. This indicates that at least a portion of this drop was due to the passage of time in the compromised surgical state., Conclusion: It was concluded that the majority of the force and stiffness generated by the transverse abdominis was transferred through the connective tissue network adhering to the internal oblique muscle. This indicates the presence of strong shear connections between the muscular layers, which suggests a composite stiffening function of the architectural design.

Background: Enduring diastasis repair is one of the yardsticks by which a successful abdominoplasty is measured, because the presence and size of diastasis recti are thought to be reliable indicators of abdominal wall laxity and protrusion. The author's study of the "normal" anatomy of diastasis challenges these concepts about diastasis recti., Methods: Ninety-two consecutive abdominoplasty patients, in whom intraoperative measurements of the linea alba were taken, were included in this study. The degree of abdominal wall protrusion was quantified by estimating the intra-abdominal fat volume in the upright patient as large, medium, or small., Results: The most striking anatomical finding was that the linea alba has a limited range of stretch, most commonly between 1 and 2 inches, regardless of the extent of the abdominal girth. Moreover, eight patients with diastasis did not manifest abdominal protrusion, and in five patients, diastasis was absent, although a significant protrusion was present. Also, the site of the widest diastasis (supraumbilical/infraumbilical) frequently did not correspond to the site of the protrusion., Conclusions: Contrary to current thought, abdominal wall protrusions are caused by the stretching of the entire abdominal wall and not only the linea alba. Thus, significant abdominal wall protrusions may occur without diastasis and flat abdomens may exhibit a diastasis. Abdominal protrusion should replace diastasis as the prime indicator of abdominal wall laxity; stretching and the decision to perform diastasis repair should be influenced primarily by the evaluation of the protrusion rather than the diastasis.

The sport of volleyball creates considerable dynamic trunk stability demands. Back injury occurs all too frequently in volleyball, particularly among female athletes. The purpose of this clinical commentary is to review functional anatomy, muscle coactivation strategies, assessment of trunk muscle performance, and the characteristics of effective exercises for the trunk or core. From this information, a conceptual progressive 3-phase volleyball-specific training program is presented to improve dynamic trunk stability and to potentially reduce the incidence of back injury among volleyball athletes. Phase 1 addresses low-velocity motor control, kinesthetic awareness, and endurance, with the clinician providing cues to teach achievement of biomechanically neutral spine alignment. Phase 2 focuses on progressively higher velocity dynamic multiplanar endurance, coordination, and strength-power challenges integrating upper and lower extremity movements, while maintaining neutral spine alignment. Phase 3 integrates volleyball-specific skill simulations by breaking down composite movement patterns into their component parts, with differing dynamic trunk stability requirements, while maintaining neutral spine alignment. Prospective research is needed to validate the efficacy of this program.

The rectus sheath has been extensively described in gross anatomic studies but there is very little information available regarding the arcuate line (AL). The aim of the present study therefore was to explore and delineate the morphology, topography and morphometry of the arcuate line and provide a comprehensive picture of its anatomy across a broad range of specimens. The AL was present in all specimens examined. In addition, the AL was found to be located at a mean of 70.2% (67.3-75.2%) of the distance between the pubic symphysis and the umbilicus, and at 33.9% (30.2-35.4%) of the distance between the pubic symphysis and the xiphoid process. This location was found to be at a mean of 2.1 +/- 2.3 cm superior to the level of the anterior superior iliac spines. Furthermore, there were three distinct types of AL morphology. In type I (65%), the fibers of the posterior rectus sheath (PRS) gradually disappeared over the transversalis fascia, creating an incomplete demarcation of the actual location of the AL. In type II (25%) the termination of the fibers of the PRS was acutely demarcated over the transversalis fascia, creating a clear border with the AL. In type III (10%) the fibers of the PRS created a double and thickened aponeurotic line. In these cases a double AL was observed. Better preoperative knowledge of the location of the AL may, in some cases, help preoperative planning to facilitate primary fascial repair, which can then be supported with on-lay mesh, depending on the clinical situation.

Incidental finding of an accessory slip of the piriformis muscle in the gluteal region is reported. Following routine dissection of the gluteal region in three formalin-fixed cadavers, an accessory slip of the piriformis was observed. The accessory slip was cleaned, attachments were identified, and dimensions were measured in two parts as fleshy and tendinous parts with a graduated scale to the nearest millimetre. The accessory slip was innervated by a small twig from the sciatic nerve. Having considered the available literature, the accessory slip of piriformis is rare, and if found, could be a cause for the undiagnosed chronic pain in the back and gluteal region, as this accessory slip may compress the sciatic nerve.

The symmetry of, and physical characteristics influencing, the thickness of the lateral abdominal muscles at rest and during abdominal exercises were examined in 57 healthy subjects (20 men, 37 women; aged 22-62 years). M-mode ultrasound images were recorded from the abdominal muscles at rest and during abdominal hollowing exercises in hook-lying. The fascial lines bordering the transvs. abdominis, obliquus internus and obliquus externus were digitized and the absolute thickness, relative thickness (% of total lateral thickness) and contraction ratio (thickness during hollowing/thickness at rest), as well as the asymmetry (difference between sides expressed as a percent of the smallest value for the two sides) for each of these parameters were determined for each muscle. Both at rest and during hollowing, obliquus internus was the thickest and transvs. abdominis the thinnest muscle. There were no significant differences between left and right sides for group mean thicknesses of any muscle; however, individual asymmetries were evident, with mean values for the different muscles ranging from 11% to 26%; asymmetry was much less for the contraction ratios (mean % side differences, 5-14% depending on muscle). Body mass was the most significant positive predictor of absolute muscle thickness, for all muscles at rest and during hollowing, accounting for 30-44% variance. Body mass index explained 20-30% variance in transvs. abdominis contraction ratio (negative relationship). The influence of these confounders must be considered in comparative studies of healthy controls and back pain patients, unless groups are very carefully matched. Asymmetries observed in patients should be interpreted with caution, as they are also common in healthy subjects.

Dorsal lumbar hernias are rare pathologies of the abdominal wall. Such hernias may manifest within the superior lumbar triangle of Grynfeltt (TG) or the triangle of Petit. The aim of our study was to identify and describe variations in the size and anatomy of the TG. The triangle was studied in 50 adult human cadavers, and dimensions and surface area were measured. The TG was identified in 82% of cases. Based on surface area parameters, we were able to classify the triangles into four distinct types. Type I (50%), or small triangles, had a surface area of <5 cm(2). Type II (22%, n=22) were defined as triangles intermediate in size with surface areas of 5-15 cm(2). Type III (10%, 10) were large triangles with surface areas of >15 cm(2). Finally, Type 0 (18%, 18) did not exhibit a triangle; instead, the aponeurosis of the transversus abdominis was enclosed by the external abdominal oblique muscle and the sacrospinalis muscle. We present these data with the hope that after further investigation in a clinical setting, they may serve practitioners in predicting which morphometric variations of the TG most predispose patients to posterior wall herniation.

Respiration requires the coordinated rhythmic contractions of diverse muscles to produce ventilatory movements adapted to organismal requirements. During fast locomotion, locomotory and respiratory movements are coordinated to reduce mechanical conflict between these functions. Using semi-isolated and isolated in vitro brain stem-spinal cord preparations from neonatal rats, we have characterized for the first time the respiratory patterns of all spinal intercostal and abdominal motoneurons and explored their functional relationship with limb sensory inputs. Neuroanatomical and electrophysiological procedures were initially used to locate intercostal and abdominal motoneurons in the cord. Intercostal motoneuron somata are distributed rostrocaudally from C(7)-T(13) segments. Abdominal motoneuron somata lie between T(8) and L(2). In accordance with their soma distributions, inspiratory intercostal motoneurons are recruited in a rostrocaudal sequence during each respiratory cycle. Abdominal motoneurons express expiratory-related discharge that alternates with inspiration. Lesioning experiments confirmed the pontine origin of this expiratory activity, which was abolished by a brain stem transection at the rostral boundary of the VII nucleus, a critical area for respiratory rhythmogenesis. Entrainment of fictive respiratory rhythmicity in intercostal and abdominal motoneurons was elicited by periodic low-threshold dorsal root stimulation at lumbar (L(2)) or cervical (C(7)) levels. These effects are mediated by direct ascending fibers to the respiratory centers and a combination of long-projection and polysynaptic descending pathways. Therefore the isolated brain stem-spinal cord in vitro generates a complex pattern of respiratory activity in which alternating inspiratory and expiratory discharge occurs in functionally identified spinal motoneuron pools that are in turn targeted by both forelimb and hindlimb somatic afferents to promote locomotor-respiratory coupling.

Spine stabilization exercises, in which patients are taught to perform isolated contractions of the transverses abdominus (TrA) during "abdominal hollowing", are a popular physiotherapeutic treatment for low back pain (LBP). Successful performance is typically judged by the relative increase in TrA thickness compared with that of the internal (OI) and external (OE) oblique muscles, measured using ultrasound. The day-to-day measurement error (imprecision) associated with these indices of preferential activation has not been assessed but is important to know since it influences the interpretation of changes after treatment. On 2 separate days, 14 controls and 14 patients with chronic LBP (cLBP) performed abdominal hollowing exercises in hook-lying, while M-mode ultrasound images superimposed with tissue Doppler imaging (TDI) data were recorded from the abdominal muscles (N = 5 on each side). The fascial lines bordering the TrA, OI and OE were digitized, and muscle thicknesses were calculated. The between-day error (intra-observer) was expressed as the standard error of measurement, SEM; SEM as a percentage of the mean gave the coefficient of variation (CV). There were no significant between-day differences for the mean values of resting or maximal thickness for any muscle, in either group (P > 0.05). The median SEM and CV of all thickness variables was 0.71 mm and 10.9%, respectively for the controls and 0.80 mm or 11.3%, respectively for the cLBP patients. For the contraction ratios (muscle thickness contracted/thickness at rest), the CVs were 3-11% (controls) and 5-12% (patients). The CVs were unacceptably high (30-50%, both groups) for the TrA preferential activation ratio (TrA proportion of the total lateral abdominal muscle thickness when contracted minus at rest). In both the controls and patients, the precision of measurement of absolute muscle thickness and relative change in thickness during abdominal hollowing was acceptable, and commensurate with that typical of biological measurements. The TrA preferential activation ratio is too imprecise to be of clinical use. Knowledge of the SEM for these indices is essential for interpreting the clinical relevance of any changes observed following physiotherapy.

This study evaluated the sport-specific characteristics of the cross-sectional areas (CSAs) of trunk muscles and trunk muscle strength in wrestlers and judokas. We also examined whether their trunk muscles and muscle strength depended on athletic performance levels in each sport. The subjects comprised 14 male collegiate wrestlers and 14 judokas. Magnetic resonance imaging was used to assess the trunk muscle CSAs at the L3-4 level parallel to the lumbar disc space. A Biodex System3 was used to measure isokinetic trunk flexor and extensor muscle strength of peak torque, work, average torque, and average power. The absolute and relative CSAs of the trunk muscles in the wrestlers and judokas were significantly different (rectus abdominis: wrestling > judo, P < 0.05; obliques: wrestling < judo, P < 0.05; quadratus lumborum: wrestling < judo, P < 0.01). We confirmed that the absolute and relative trunk extensor and flexor strength of peak torque, work, and average torque were significantly higher in the collegiate wrestlers than in judokas. On athletic performance, the tendency of the CSAs and muscular strength of trunk muscles was not consistent with athletic performance levels in each sport. Our findings indicated that the sport-specific characteristics of the CSAs of the trunk muscles and trunk muscle strength obviously differed between the 2 similar sports. Athletes should practice the sport-specific training of trunk muscles and develop sport specificity in their sports. Particularly, wrestlers have to train in trunk flexion and extension motions, and judokas need to strengthen trunk rotation and lateral flexion motions. This information will be available for athletes as well as strength and technical training coaches in wrestling, judo, and the other sports.

Aim: The abdominal wall continues to be a topic of investigation for the evaluation of its healing in terms of morphology and resistance. In the present investigation, transverse and longitudinal laparotomies were studied comparatively., Methods: Thirty rabbits were divided into two groups: Group 1 (n=10) longitudinal laparotomy, Subgroup 1A (n=5) suture of the anterior and posterior sheaths of the abdominal rectus muscle and of the peritoneum, Subgroup 1B (n=5) suture of the anterior sheath of the abdominal rectus muscle; Group 2 (n=20) transverse laparotomy, Subgroup 2A (n=5) suture of the anterior and posterior sheaths of the abdominal rectus muscle and of the peritoneum, Subgroup 2B (n=5) suture of only the anterior sheath of the abdominal rectus muscle, Subgroup 2C (n=5) suture of the abdominal rectus muscle and of its anterior sheath on a single plane, Subgroup 2D (n=5) repair of the posterior sheath of the abdominal rectus muscle together with the peritoneum, followed by suture of the abdominal rectus muscle complemented with suture of the anterior sheath of the same muscle. After 17 days, two peritoneal aponeurotic muscular segments of the scar were removed for the evaluation of resistance and of histological aspects., Results: The resistance values detected for each group showed 1A>1B, 1A>2A and 1B>2B, and 2B>2C>2D>2A (P=0.014). Dehiscence, infections and adhesions were more frequent in Group 2. Histology revealed muscular degeneration and necrosis, with mature fibrous connective scar tissue replacing muscle tissue., Conclusion: Transverse muscle section causes greater muscle weakening and leaving the peritoneum open does not alter the resistance of the scar.

Peter of Abano was greatly interested to the anatomy. Sure indications of his dissections are had; in the De venenis he reported the first autopsy, antecedent to 1316, of which sure news in Padua is had. The table of abdominal muscles, first published in the edition Venetiis 1496 of the Conciliator, is carefully considered.

The inguinal portions of the internal oblique and transversus abdominis muscles are generally described as arising from the inguinal ligament. Previous authors have shown that this description is incorrect. A new dissection study in 15 lightly embalmed cadavers confirms that in reality the inguinal portions of these muscles arise from a thickened strip of ilipsoas fascia that forms the superolateral part of the ilio-pectineal arch. Details are given of a new dissection technique that fully exposes the deep aspect of the inguinal ligament, without disrupting its continuity. The historical background of the persistent textbook error is explored. It originated at a time when there was widespread descriptive and semantic confusion regarding the structure now known as the inguinal ligament., ((c) 2007 Wiley-Liss, Inc.)

Background: Extrapolation of rat testicular descent studies to humans has been criticized because of anatomical differences of the cremaster muscle. Human cremaster is described as a thin strip rather than a large, complete sac as in rats, which is proposed to be more important in propelling the testis during descent. This study investigated cremaster muscle anatomy and ontogeny in both normal and cryptorchid rat models., Methods: Gubernacula from 4 groups of neonatal rats were sectioned longitudinally and transversely: normal Sprague-Dawley, capsaicin pretreated, flutamide pretreated, and congenital cryptorchid rats. Gubernacula were stained with hematoxylin-eosin, Masson trichrome, and desmin immunohistochemistry to study muscle development., Results: Myoblasts are more numerous at the gubernacular tip, whereas the most differentiated muscle is proximal. Rat cremaster develops as an elongated strip rather than a complete sac derived from abdominal wall muscles. Flutamide and capsaicin pretreatment disrupts development., Conclusion: Rat cremaster muscle develops as a strip, bearing close resemblance to human cremaster muscle, permitting extrapolation of cremaster function to human testicular descent. The cremaster muscle appears to differentiate from the gubernacular tip during elongation to the scrotum, and requires intact sensory innervation and androgen.

The anatomy of the middle layer of lumbar fascia (MLF) is of biomechanical interest and potential clinical relevance, yet it has been inconsistently described. Avulsion fractures of the lumbar transverse processes (LxTP's) are traditionally attributed to traction from psoas major or quadratus lumborum (QL), rather than transversus abdominis (TrA) acting via the MLF. This attachment is also absent from many biomechanical models of segmental control. The aims of this study were to document: (1) the morphology and attachments of the MLF and (2) the attachments of psoas and QL to the LxTP's. Eighteen embalmed cadavers were dissected, measuring the thickness, fibre angle and width of the MLF and documenting the attachments of MLF, psoas and QL. The MLF was thicker at the level of the LxTP's than between them (mean 0.62: 0.40 mm). Psoas attached to the anteromedial surface of each process and QL and TrA to its lateral border; QL at its upper and lower corners and TrA (via the MLF) to its tip. In three cadavers, tension applied to the MLF fractured a transverse process. The MLF has a substantial and thickened attachment to the tips of the LxTP's which supports the involvement of TrA in lumbar segmental control and/ or avulsion fracture of the LxTP's.

A suitable dynamic 3D model that allows the simulation of the inguinal region with real-time performance on a personal computer was developed. A geometric model adjusted to real data was created by means of semiautomatic contour segmentation of anatomic units from the visible human project and data generated from classical anatomic information. A dynamic model included converting muscular units from their continuous geometric representation into a set of voxels and then real-time interaction and performance. The current implementation enables deformation of the realistic model associated with pushing and stretching interaction, allowing immersion in the anatomy of the inguinal structures. The model does not allow simulation of surgical interventions.

This study aimed to examine how the muscularity of the abdomen at the umbilicus level differs between sedentary middle-aged and young men. Magnetic resonance imaging was applied to determine the cross-sectional areas of skeletal muscle, subcutaneous fat, and interperitoneal tissue in 43 middle-aged (40 58yrs) and 38 young (21-29 yrs) men. The cross-sectional area of the skeletal muscle was analyzed as the sum of those of the rectus abdominis, abdominal oblique, lower back, and iliopsoas skeletal muscle groups. The middle-aged men showed greater waist circumference and whole abdominal cross-sectional area than the young men. In addition, the cross-sectional areas of subcutaneous fat and interperitoneal tissue were greater in the middle-aged men than in the young men. However, the total cross-sectional area of the skeletal muscle was similar between the two groups, although its percentage to the whole abdominal cross-sectional area was higher in the young men compared to the middle-aged men. Among the four skeletal muscle groups analyzed, the percentage of the cross-sectional areas in abdominal oblique muscles to that of total skeletal muscle was higher in the middle-aged men than in the young men and that of the lower back muscles was the reverse. These results were similar even when cross-sectional area data were analyzed using a subsample (33 middle-aged and 23 young men) matched for body height and mass. Thus, the present study indicated that the total muscularity of the abdomen at the umbilicus level was similar between the middle-aged and young men, but the relative distributions of lower back and abdominal oblique muscles varied between the two generations.

The aim of the study was to estimate the prevalence of delineation of semi circular or linea arcuata (arcuate line of Douglas) (LA) during 64-row multidetector Computed Tomography (mdCT) of the abdomen and to illustrate the so-called linea arcuata hernia (LAH), a peculiar type of interstitial parietal hernia of the anterior abdominal wall consisting of an ascending protrusion of intraperitoneal structures under the LA. The mdCT abdominal wall anatomy of a continuous series of 315 unselected patients was retrospectively reviewed and explored with multiplanar reformations (MPR). Considering a grade 1 lesion (G1) as a single delineation of the LA due to minimal bulging of intraperitoneal fat, a grade 2 hernia (G2) as a substantial herniation under the LA and grade 3 hernia (G3) as a frank prominent herniation of peritoneal structures (essentially omental fat and/or intestinal loops), lesions of all types were found in 8.57% of patients with more than 81% of lesions being G1; this prevalence reached 14.97% in men but only 1.35% in women (M:F sex ratio 12.5:1); all lesions were found in patients older than 51 years and 76% of them were older than 71 years with a great majority of men. Most patients were absolutely free of symptoms related to theses abnormalities. The anatomy of the rectus abdominis sheath and LA are reviewed and the mdCT signs of LA and LAH are described and illustrated. In conclusion, 64-row mdCT can frequently delineate the linea arcuata (LA) and more rarely linea arcuata hernias (LAH), particularly in old men, but these abnormalities mostly represent fortuitous asymptomatic findings.

In the segmented axial musculature of fishes and amphibians, the patterns of muscle fiber shortening depend on both the orientation of muscle fibers relative to the long axis of the body as well as the distance of fibers from the neutral axis of bending (vertebral column). In this study we use the relatively simple architecture of salamander hypaxial muscles to explore the separate and combined effects of these morphological features on muscle fiber strains during swimming. In Siren lacertina the external oblique (EO) muscle has more obliquely oriented muscle fibers and is located further from the neutral axis of bending than the internal oblique (IO) muscle. To examine the effect of muscle fiber angle on strain patterns during swimming, we used sonomicrometry to quantify architectural gear ratio (AGR=longitudinal strain/fiber strain) in these two hypaxial muscles. By comparing the muscle fiber strains and shortening velocities of the EO and IO during swimming, we test whether variation in mediolateral position of the muscle layers is counteracted by their differences in AGR. We find that despite substantial differences in mediolateral position, the EO and IO undergo similar fiber strains and shortening velocities for a given amount of axial bending. Our results show that variation in muscle fiber angle acts to counteract differences in mediolateral position, thereby minimizing variation in muscle fiber strain and shortening velocity during swimming. These results highlight the significance of both muscle architecture and muscle moment arms in determining the fiber strains required for a given movement., ((c) 2007 Wiley-Liss, Inc.)