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At least 127 records · Page 7Linked to original sources
PubMed1986

Rib cage motion and muscle use in high tetraplegics.

In an attempt to assess the action of the sternocleidomastoid muscles on the human rib cage, we studied the pattern of rib cage motion in 2 patients with complete transection of the upper cervical cord. Measurements of rib cage motion were obtained with magnetometers and chest roentgenograms, and concentric needle electrodes were used to record the electromyograms (EMG) of various respiratory muscles. Spontaneous quiet breathing elicited a large amount of phasic inspiratory EMG activity not only in the sternocleidomastoids, but also in the trapezii, platysma, mylohyoid, and sternohyoid muscles. This pattern of muscle use was associated with substantial rib cage deformation. During spontaneous inspiration both patients showed a clear-cut decrease in lower rib cage transverse diameter, and they both had a cranial displacement of the sternum and an increase in upper rib cage anteroposterior diameter that was disproportionately larger than the increase in lower rib cage anteroposterior diameter. Radiographic measurements confirmed these deformations but also demonstrated that the upper rib cage transverse diameter increased rather than decreased with inspiration. These results indicate that: (1) Patients with high tetraplegia use many neck muscles in addition to the sternocleidomastoids to breathe; (2) The synchronous contraction of these muscles acts to pull the sternum cranially, expands the upper rib cage, and causes paradoxical inward displacement of the lateral walls of the lower rib cage; (3) As in dogs, the motion of the upper rib cage in humans is more tightly linked to the sternum than that of the lower rib cage.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗
PubMed2006

Results of vascularized rib grafts in complex spinal reconstruction.

BACKGROUND: The application of vascularized rib grafts in spine surgery has been limited to the treatment of kyphosis with anterior placement of the rib graft to facilitate anterior spine arthrodesis. The outcomes following use of vascularized rib grafts in complex spinal reconstruction have not been adequately evaluated. The purpose of this study was to determine the results, including the time to osseous union and complications, following anterior or posterior placement of pedicled vascularized rib grafts for complex spinal reconstruction. METHODS: The medical records and images of all patients in whom a vascularized rib graft had been used for a multisegmental spine reconstruction at a single institution between 1994 and 2004 were retrospectively reviewed. Eighteen patients (mean age, 45.3 years) who had been followed for an average of 31.8 months were identified. Details regarding indications, the levels that were spanned, the graft length, the time to union, and complications were evaluated. RESULTS: The preoperative diagnoses included metastatic or primary tumor (thirteen patients) and progressive kyphosis secondary to chronic osteomyelitis (two), injury (one), congenital anomalies (one), or implant failure (one). On the average, 4.4 levels were fused and 1.9 vertebral bodies were excised. All eighteen arthrodeses included various forms of allograft and/or autograft material, and instrumentation was used, in addition to the vascularized rib graft, in twelve patients. The mean rib length was 16.1 cm, and a rib between the fifth and eleventh ribs, inclusive, was used, depending on the location of the spinal reconstruction. The average time to union was 6.8 months, and all rib grafts united. There were no complications specific to the rib-harvesting procedure. CONCLUSIONS: The use of a vascularized rib graft in complex spinal reconstruction adds little time to the overall procedure, is associated with low morbidity, and appears to offer substantial benefits to the patient.

Adolescent↗
PubMed1990

Rib fractures in children: a marker of severe trauma.

The early recognition of life-threatening injury is paramount to the prompt initiation of appropriate care. This study assesses the importance of multiple rib fractures as a marker of severe injury in children. We analyzed physiologic, etiologic, and injury data for 2,080 children with blunt or penetrating trauma aged 0-14 years consecutively admitted to a Level I pediatric trauma center. Analysis of variance, Student's t-test, and the Chi-square test of independence were used to test for differences between children with rib fractures and other children. Probability of survival was modeled using stepwise logistic regression. There were 14 deaths among 33 children with rib fractures, a mortality rate of 42%. Child abuse accounted for 63% of the injuries to children less than 3 years old, while pedestrian injuries predominated among older children. Children with rib fractures were significantly more severely injured than children with blunt or penetrating trauma but without rib fractures. When compared to children without rib fractures, children with rib fractures had a higher mortality rate, but no statistically significant difference in morbidity. The mortality rate for the 18 children with both rib fractures and head injury was 71%. A logistic model with variables measuring severity of head injury and number of ribs fractured correctly predicted survival in more than 85% of children with thoracic trauma. Although rib fractures are rare injuries in childhood, they are associated with a high risk of death. The risk of mortality increases with the number of ribs fractured. The combination of rib fractures and head injury was usually fatal.

Adolescent↗
PubMed2003

Defining regional variation in the material properties of human rib cortical bone and its effect on fracture prediction.

This paper presents the results of dynamic material tests and computational modeling that elucidate the effects of regional rib mechanical properties on thoracic fracture patterns. First, a total of 80 experiments were performed using small cortical bone samples from 23 separate locations on the rib cages of four cadavers (2 male, 2 female). Each specimen was subjected to dynamic three-point bending resulting in an average strain rate of 5 +/- 1.5 strain/s. Test coupon modeling was used to verify the test setup. Regional variation was defined by location as anterior, lateral, or posterior as well as by rib level 1 through 12. The specimen stiffness and ultimate stress and strain were analyzed by location and rib level. Second, these material properties were incorporated into a human body computational model. The rib cage was partitioned into anterior, lateral, and posterior segments and the material properties were varied by location using an elastic-plastic material model. A total of 12 simulations with a rigid impactor were performed including 2 separate material assumptions, original and modified rib properties for regional variations, 3 separate impactor velocities, and 2 directions, anterior and lateral. The data from the material tests for all subjects indicate a statistically significant increase in the average stiffness and average ultimate stress for the cortical bone specimens located in the lateral (11.9 GPa modulus, 153.5 MPa ultimate stress) portion of the ribs versus the anterior (7.51 GPa, 116.7 MPa) and posterior (10.7 GPa, 127.7 MPa) rib locations. In addition, the stiffness, ultimate stress, and ultimate strain for all subjects are significantly different by rib level with each variable generally increasing with increasing rib number. The results from the computational modeling for both frontal and lateral impacts illustrate that the location and number of rib fractures are altered by the inclusion of rib material properties that vary by region.

Journal Article↗
PubMedDate not supplied

Postnatal evolution of supernumerary ribs in rats after a single administration of sodium salicylate.

Radiographs were used to follow the postnatal evolution of 14th ribs in rat pups. Initially, 30 pregnant female rats were randomly distributed into two groups receiving 0 or 300 mg kg(-1) sodium salicylate on day 9 of pregnancy. In the treated group, adverse effects were noted on body weight changes and food consumption during the 2 days following dosing. At birth, a high majority of pups had extra ribs at the 300 mg kg(-1) dose. Radiographs done on postnatal days 1, 6, 14, 28 and 54 showed a reduction in the incidence of rudimentary ribs only, whereas extra ribs, often associated with 27 presacral vertebrae, had the same incidence from birth to adult stage. Furthermore, extra ribs seemed to exhibit similar growth evolution to the other thoracic ribs. This work helps to clarify the postnatal evolution of supernumerary ribs because it was performed on the same animals from birth to adult stage, showing that the reversibility was related to rib length and, in consequence, concerned the rudimentary ribs only. The coexistence of additional presacral vertebrae primarily with extra ribs suggests that both kinds of supernumerary ribs (rudimentary and extra) might be different phenomena and could be considered separately in developmental toxicology studies.

Abnormalities, Drug-Induced↗
PubMed1998

[Repair of intrathoracic visceral damage using video-assisted thoracoscopic surgery for blunt chest trauma and rib fixation at the site of mini-thoracotomy].

We treated three patients with intrathoracic visceral damage caused by severely dislocated fractured ribs resulting from blunt trauma by using video-assisted thoracoscopic surgery (VATS) and rib fixation through a mini-thoracotomy. Under general anesthesia and unilateral respiration, the thoracic cavity was inspected with a thoracic video scope through the port inserted through the thoracic drainage opening which was made upon arrival at hospital. As the visceral damage seemed restorable under VATS, a mini-thoracotomy was positioned just above the rib fracture. Two thoracic ports were inserted through the site of rib fracture or through the intercostal space and then VATS was performed using three ports. After the restoration of intrathoracic visceral damage, the fractured rib was fixated using a bioabsorbable poly-L-lactide rib fixation pin or a marlex mesh. Lung injuries were sutured and ligated under VATS in two of our cases and a spur of the fractured rib was shaved in one case. Only severely dislocated ribs were fixated through the mini-thoracotomy in all cases. Air leakage stopped just after this procedure and there were no complications. The rib fixation and bone regeneration were excellent after this procedure. The advantages of this method are the visceral restoration under VATS through a mini-thoracotomy and the ability to perform rib fixation without injuries to the intercostal muscle, artery, vein or nerve. This operative procedure is recommended for intrathoracic visceral damage caused by severely dislocated rib fracture.

Adult↗
PubMed1988

Measurements of the three-dimensional shape of the rib cage.

A stereoradiographic method was developed to measure the three-dimensional shape of the rib cage in vivo in order to provide descriptive data and to study symmetry in the normal population. The method is also intended for use in description of rib asymmetry in scoliosis. Rib midlines were reconstructed from digitized points on lines drawn through the middle of each rib image in stereo-radiographs of the rib cage. The method relied on pairing points in one image with a corresponding point found in the second image. The error term obtained from a Direct Linear Transformation (DLT) reconstruction program was used for optimizing this correspondence. The method was used on test objects of known shape where the standard deviation of measurement errors was found to be 0.72 mm. Studies in which different sets of points on the rib midlines were selected for digitizing showed that the precision of the method was 1.04 mm (S.D.). Rib shape was described by intrinsic measurements (arc and chord length, maximum curvature and enclosed area) and rib orientation by extrinsic measurements (frontal and lateral angulations and posterior rib cage rotation). No statistically significant rib shape asymmetry was found among ten subjects without spinal or thoracic abnormalities, although a trend of inequality of rib angulation at all anatomical levels was observed.

Biomechanical Phenomena↗
PubMed2005

Prevalence of rib anomalies in normal Caucasian children and childhood cancer patients.

PURPOSE: To evaluate the prevalence of abnormalities of rib development in normal Caucasian children and patients with childhood cancer. MATERIALS AND METHODS: Chest radiographs of 881 Caucasian pediatric controls and 906 childhood cancer patients were reviewed, and independently scored by four blinded observers, using strict definitions. Prevalences of 6 major rib anomaly categories in controls were compared to their prevalence in the total group of childhood cancer patients, and the 12 individual larger tumor groups using Chi-square tests. RESULTS: Values in the control population were generated for the occurrence of six major rib anomaly categories; cervical rib anomalies were present in 6.1% of controls, aplasia of 12th ribs in 6.6%, lumbar ribs in 0.9%, bifurcations in 0.7%, synostosis-bridging in 0.3%, and segmentations were not found. The overall prevalence of total rib anomalies in cases and controls was equal (14.9% and 14.2%, respectively). Cervical rib anomalies were found significantly more often in cases (8.6%) compared to controls (p-value=0.047), three groups accounting for this higher prevalence: 12.1% of acute lymphoblastic leukemia patients (p=0.011), 18.2% of astrocytoma patients (p=0.023), and 14.7% of germ cell tumor patients (p=0.046) had a cervical rib anomaly. CONCLUSION: Prevalence figures for the presence and type of rib anomalies in a large group of normal Caucasian children were generated. In childhood cancer patients a significantly higher prevalence of cervical rib anomalies was demonstrated in patients with acute lymphoblastic leukemia, astrocytoma, and germ cell tumors.

Adolescent↗
PubMed2003

Contribution of somitic cells to the avian ribs.

The traditional view that all parts of the ribs originate from the sclerotome of the thoracic somites has recently been challenged by an alternative view suggesting that only the proximal rib derives from the sclerotome, while the distal rib arises from regions of the dermomyotome. In view of this continuing controversy and to learn more about the cell interactions during rib morphogenesis, this study aimed to reveal the precise contributions made by somitic cells to the ribs and associated tissues of the thoracic cage. A replication-deficient lacZ-encoding retrovirus was utilized to label cell populations within distinct regions of somites 19-26 in stage 13-18 chick embryos. Analysis of the subsequent contributions made by these cells revealed that the thoracic somites are the sole source of cells for the ribs. More precisely, it is the sclerotome compartment of the somites that contributes cells to both the proximal and distal elements of the ribs, confirming the traditional view of the origin of the ribs. Results also indicate that the precursor cells of the ribs and intercostal muscles are intimately associated within the somite, a relationship that may be essential for proper rib morphogenesis. Finally, the data from this study also show that the distal ribs are largely subject to resegmentation, although cell mixing may occur at the most sternal extremities.

Animals↗
PubMed2000

Rib fractures in infants: red alert! The clinical features, investigations and child protection outcomes.

OBJECTIVE: To examine clinical features, investigation methods and outcomes of infants with rib fractures. METHODOLOGY: All infants aged 2 years or younger who presented over a 5-year period with documented rib fractures were identified from the medical records database of a tertiary referral paediatric hospital and data collected by retrospective chart review. Additional data regarding notifications and placements were obtained from the Department of Families Youth and Community Care, Queensland. RESULTS: Rib fractures were attributed to child abuse in 15 of 18 infants identified. The initial presentation in the abused infants was most often as a result of intracranial pathology and limb fractures. In four cases the rib fractures were incidental findings when abuse had not been suspected. Bone scintigraphy revealed eight previously undetected rib injuries in four cases. In three cases of abuse, the rib fractures were an isolated finding. Three of the infants with inflicted rib injuries were discharged home. In one such infant a significant re-injury occurred. Three returned home with implicated adults no longer in residence, and nine spent a mean period of 12 months in foster care. CONCLUSIONS: Rib fractures in infancy are usually caused by severe physical abuse. Accidental rib fractures are rare in infants and result from massive trauma. Rib fractures, multiple or single, may occur in isolation in abused infants. The implications of such injuries must be recognized to ensure appropriate, safe and consistent child protection outcomes. Bone scintigraphy is more sensitive than radiographs in the detection of acute rib fractures and should be performed in all cases of suspected infant abuse.

Acute Disease↗
PubMed1996

Rib motion modulates inspiratory intercostal activity in dogs.

1. A test was performed of the hypothesis that the motion of the ribs during inspiration modulates, via changes in spindle afferent activity, the activation of the inspiratory intercostal muscles. The electrical activity of the parasternal intercostal, external intercostal, and levator costae muscles in anaesthetized spontaneously breathing dogs was thus recorded during manipulation of the inspiratory displacement of the ribs over a wide range of rib motion. 2. In agreement with the hypothesis, the external intercostal and levator costae muscles lengthened and showed increased inspiratory activities when the normal inspiratory cranial motion of the lower rib was reduced or reversed into an inspiratory caudal motion. Conversely, the inspiratory activities decreased when the inspiratory cranial motion of the rib and the inspiratory shortening of the muscles was augmented. The inspiratory activity of the parasternal intercostal remained unchanged throughout. 3. However, when the two ribs making up the interspace were linked together so that the external intercostal muscle was constant in length, the relationship of muscle activity to rib motion was maintained. 4. In addition, when the upper rather than the lower rib of the interspace was manipulated, the relationship between the change in muscle length and inspiratory activity was reversed, so that activity decreased when the muscle was lengthened and increased when the muscle was shortened. The relationship of muscle activity to lower rib motion, however, was still maintained. 5. These observations thus indicate that rib motion triggers proprioceptive reflexes which, regardless of the changes in length of the individual muscles, make the external intercostal inspiratory activity exquisitely sensitive to the direction of rib displacement.

Animals↗
PubMed1982

Action of the diaphragm on the rib cage inferred from a force-balance analysis.

Displacements of the rib cage are determined by the intrinsic passive properties of the rib cage, rib cage musculature, pleural and abdominal pressures, and the diaphragm. The diaphragm's mechanical actions on the rib cage are inferred from a force-balance analysis in which the diaphragm is seen to cause expansion of the rib cage by pulling cephalad at its insertions on the lower ribs (insertional component) and by raising intra-abdominal pressure, which pushes outward on the diaphragm's zone of apposition to the rib cage (appositional component). Goldman and Mead suggested that the diaphragm, acting alone, could drive both the rib cage and abdomen on their passive characteristics. The force-balance analysis shows that the diaphragm's inspiratory action on the rib cage is less than predicted by Goldman and Mead, but that in the special circumstances of their experiment (low lung volumes), the appositional component is large and the rib cage can be driven close to its passive characteristics. The force-balance analysis is consistent with recent observations by other investigations and is incompatible with the model proposed by Macklem and colleagues and with the Goldman-Mead hypothesis. Experiments on three subjects produced data consistent with the force-balance analysis, showing that the inspiratory action of the diaphragm on the rib cage is greatest at low lung volumes.

Abdominal Muscles↗
PubMed1985

Relationship between respiratory muscle electromyogram and rib cage motion in tetraplegia.

In an attempt to understand the intersubject variation in rib cage motion in tetraplegia, and to assess the isolated action of the diaphragm on the human rib cage, we studied the pattern of rib cage motion in relation to the pattern of nondiaphragmatic respiratory muscle electromyogram (EMG) in 20 tetraplegic patients breathing at rest in the seated posture. The general pattern included a greater expansion of the lower than of the upper rib cage, and a greater and earlier expansion of the lower rib cage in its transverse than in its anteroposterior (AP) diameter. However, whereas the upper rib cage moved paradoxically inward with inspiration in 11 patients, it did not move or slightly expanded in 9 patients; in 1 of these, all rib cage diameters increased in the same proportion during inspiration as during relaxation. This intersubject variation was not related to the duration of tetraplegia, the pattern of the abdominal muscle EMG, or the presence of continuous spastic EMG activity in the parasternal intercostals. By contrast, it was related in part to the pattern of scalene EMG activity: upper rib cage AP paradox was present in 7 of 8 patients with spastic or silent scalenes but only in 4 of 12 patients with phasic inspiratory scalene EMG activity. When studied during quiet breathing in the supine posture, the 8 subjects with denervated scalene, intercostal, and abdominal muscles still showed inspiratory increase in the rib cage transverse diameter, but in 7 patients the lower rib cage AP diameter decreased in concert with the upper rib cage AP diameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1998

Dermomyotomal origin of the ribs as revealed by extirpation and transplantation experiments in chick and quail embryos.

To elucidate role of the dermomyotome in the formation of the axial skeleton, we performed extirpation and transplantation experiments on the dermomyotomes in chick and quail embryos. When the thoracic dermomyotomes of chick embryos were removed, the intercostal muscles and the distal ribs were deficient, while the proximal ribs were more or less normal. Quail tissues including the dermomyotome, the ectoderm and the medial edge of lateral plate, were transplanted to replace chick dermomyotomes. In these chimeras, the ribs, which would be deficient without the back-transplantation, were recovered. The cells of the recovered part of the ribs as well as the intercostal muscles were derived from the quail transplants. These findings suggest that the distal rib originated from the dermomyotomes and not the sclerotome as previously believed. To localize the origin of the distal rib further, we removed restricted regions of the dermomyotomes along the mediolateral and the rostrocaudal axis. The more lateral the part of the dermomyotomes that we removed, the more distal the part of the ribs affected. On the contrary, when the rostral and caudal edges of the dermomyotomes were removed, only the vertebral ribs showed extensive deficiencies while removal of the middle part between the edges caused less deficiency. The sternal ribs were not deficient in either case, but were extensively affected when the entire lateral edge of dermomyotomes was included in the region removed. We conclude that the lateral edges of the dermomyotomes are the primordia of the sternal ribs, and the rostral and/or caudal edges of the medial part of dermomyotomes are the primordia of the distal part and not of the proximal part of the vertebral ribs.

Animals↗
PubMedDate not supplied

The subclavian artery in 16 patients with complete cervical ribs.

In a series of 16 patients presenting with symptoms due to the presence of a complete cervical rib, 8 complained of neurological symptoms only and 8 presented with major vascular symptoms. There were 21 complete cervical ribs in this series, 5 patients having bilateral cervical ribs, and these were excised. At operation particular attention was paid to the anatomy and pathology of the subclavian artery in relation to the cervical rib. Two anatomical variants were present. In type A cervical rib (16 cases) the subclavian artery crossed the first rib medial to the exostosis and all patients with major vascular symptoms were in this category. In type B (5 cases) the subclavian artery crossed the first rib lateral to the exostosis and symptoms, when present, were neurological rather than vascular. The two groups can be distingushed clinically and this may be of prognostic value. Post-stenotic dilatation of the subclavian artery acompanied 15 of the 21 complete cervical ribs and was attributed to compression of the artery between the cervical rib and the anterior scalene muscle. In 8 instances the post-stenotic dilatation was complicated by aneurysm and peripheral thrombo-embolism and this was regarded as a secondary phenomenon due to intermittent trauma at cost-clavicular level. A follow-up of up to 9 years would indicate that post-stenotic dilatation of mild or moderate degree is adequately treated by resection of the cervical rib and exostosis on first rib. When an aneurysm is present with localised disruption of the arterial wall with mural thrombus, it is necessary also to excise the aneurysm for, otherwise, there is a risk of further thrombo-embolic episodes.

Adult↗
PubMed2003

Effects of expiratory rib cage compression and/or prone position on oxygenation and ventilation in mechanically ventilated rabbits with induced atelectasis.

INTRODUCTION: Expiratory rib cage compression is a chest physiotherapy technique known as "squeezing" technique in Japan. It has been claimed that rib cage compression effectively treats and/or prevents lung collapse, but no studies have been reported on rib cage compression focused on improving ventilation and/or oxygenation in subjects with collapsed lung. Therefore, we studied whether rib cage compression, with and without prone positioning, improves the ratio of P(aO)(2) to fraction of inspired oxygen (P(aO)(2)/F(IO)(2)), P(aCO)(2), or dynamic compliance of the respiratory system. METHODS: We used anesthetized adult rabbits with induced atelectasis. An endotracheal tube and an 18-gauge catheter were placed into the airway via a tracheostoma, and pressure-controlled mechanical ventilation was used. To create atelectasis, artificial mucus was infused into the airway via the catheter. The rabbits were randomly assigned to one of 4 groups ( = 10 in each group): (1) supine without rib cage compression, (2) supine with rib cage compression, (3) prone without rib cage compression, and (4) prone with rib cage compression. Each rib cage compression session lasted for 5 min and was repeated 5 times every 30 min. After these interventions for 180 min all animals were placed in the supine position for 120 min. RESULTS: The prone-position groups had significantly higher P(aO)(2)/F(IO)(2) than the supine-position groups at 60 min after the beginning of the intervention, and at 60, 90, and 120 min after the end of the intervention (p < 0.05). Rib cage compression did not significantly affect P(aO)(2)/F(IO)(2), P(aO)(2), or dynamic compliance. CONCLUSIONS: It is unlikely that rib cage compression re-expands collapsed lung. Prone positioning improved oxygenation in rabbits with induced atelectasis.

Animals↗
PubMed2002

The Double Rib Contour Sign (DRCS) in lateral spinal radiographs: aetiologic implications for scoliosis.

UNLABELLED: All lateral spinal radiographs in idiopathic scoliosis show a DRC sign of the thoracic cage, a radiographic expression of the rib hump. The outline of the convex overlies the contour of the concave ribs. The aim of this study is to assess this DRC sign in children with and without Late Onset Idiopathic Scoliosis (LOIS) with 10 degrees -20 degrees Cobb angle, and to examine whether in scoliosis the deformity of the thorax or that of the spine develops first. METHODS AND MATERIAL: The radiographs of 133 children referred to hospital in a school screening study were examined. There were 47 boys and 86 girls, 13.28 and 13.39 years old respectively. The Cobb angle was measured and the radiological lateral spinal profile (LSP) was appraised from an angle made by a line drawn down the posterior surface of each vertebral body (T1-L5) and by the vertical. The children, boys and girls, were divided in 5 groups, namely: 1) with straight spines, 2) with spinal curvature having a Cobb angle <10 degrees, 3) with thoracic, 4) thoracolumbar and 4) lumbar curves 10 degrees -20 degrees. For quantification of the DRC sign, the "rib index" was defined as d1/d2 ratio, where dl expresses the distance from the most extended point of the most projecting rib contour (RC) to the posterior margin of the corresponding to point vertebra and d2 expresses the distance from the posterior margin of the same vertebra to the most protruding point of the least projecting RC. In a symmetric and non-deformed thorax, these two RC lines are superimposed and the "rib index" is 1. RESULTS: The statistical descriptive of d1 and d2 in boys and girls are presented together because they are not statistically different. There are no sex differences of the "rib index" which is 1.45, 1.51, 1.56, 1.59, 1.47 for the 5 respectively aforementioned groups. According to statistical analysis, there is no correlation of the Cobb angle with the "rib index" of thoracic, thoracolumbar and lumbar scoliosis groups. The DRC sign is present in all referrals and scoliotics. The data show a correlation of the "rib index" with each of T2, T3, T4, T5, T6 and T7 LSP in girls with lumbar curvatures. DISCUSSION: The DRCS primarily appears because of the rib deformation and secondarily because of the vertebral rotation, as it could be present in straight spines with no vertebral rotation. In all our school-screening referrals, (having ATI > or = 7 degrees), the thorax deformity, in terms of the DRC sign, has already been developed. 70% of these children were scoliotic. The others had a curvature of less than 9 degrees of Cobb angle (10%) or they were children with straight spines (20%) who were followed because of their existing rib hump. The non-scoliotics were 1,5-2 years younger than the ones who had already developed scoliosis, and they had both approximately a "rib index" of 1,5. The DRC sign is present in all referrals. In contrary, there is no scoliotic spine without it, as the DRC sign is always present in scoliotic lateral spinal radiographs with no exception. This observation supports our hypothesis that in idiopathic scoliosis, the deformity of the thorax develops first and then the deformity of the spine follows.

Adolescent↗
PubMed2002

Fabricational morphology of oblique ribs in bivalves.

The formation of oblique ribs of bivalve shells usually has been attributed to processes of reaction-diffusion of morphogens from cell to cell at the mantle margin or neural activation and lateral inhibition in the mantle. In particular, such ribs appear with high rates of lateral diffusion. Nevertheless, theoretical models fail to explain either partially or wholly some varieties of oblique ribs. After surveying the modes of formation of the shell and oblique ribs by the bivalve mantle and associated fabricational defects, I have determined that the mantle is able to develop an elaborate behavior in order to displace the rib in a particular direction during growth. The mantle margin is, therefore, not only the shell-secreting organ, but also the main morphogenetic unit. In particular, there are two main fabricational strategies. In forms with strict contact guidance (SCG) the mantle is able to project far enough beyond the shell margins so as to feel the already formed reliefs and to align new growth increments of the ribs in the appropriate directions. The shell margin is always strongly reflected. In bivalves with reduced contact guidance plus constant lateral shift (RCG), the margin is usually acute and the information about ribs available to the mantle is reduced. During rib construction the mantle extrudes slightly from the shell edge and then pushes laterally by muscular action; in this way, the new growth increment of the rib is displaced laterally on a small scale. The contact-guidance model is supported also by the homogeneous structure of the shell-secreting mantle. From the morphogenetic standpoint, oblique ribs are related to commarginal ones and both differ completely from other ribbing patterns of bivalves.

Animals↗