Real-Time Back Surface Landmark Determination Using a Time-of-Flight Camera

Postural disorders, their prevention, and therapies are still growing modern problems. The currently used diagnostic methods are questionable due to the exposure to side effects (radiological methods) as well as being time-consuming and subjective (manual methods). Although the computer-aided diagnosis of posture disorders is well developed, there is still the need to improve existing solutions, search for new measurement methods, and create new algorithms for data processing. Based on point clouds from a Time-of-Flight camera, the presented method allows a non-contact, real-time detection of anatomical landmarks on the subject’s back and, thus, an objective determination of trunk surface metrics. Based on a comparison of the obtained results with the evaluation of three independent experts, the accuracy of the obtained results was confirmed. The average distance between the expert indications and method results for all landmarks was 27.73 mm. A direct comparison showed that the compared differences were statically significantly different; however, the effect was negligible. Compared with other automatic anatomical landmark detection methods, ours has a similar accuracy with the possibility of real-time analysis. The advantages of the presented method are non-invasiveness, non-contact, and the possibility of continuous observation, also during exercise. The proposed solution is another step in the general trend of objectivization in physiotherapeutic diagnostics.

Predicting spinal profile using 3D non-contact surface scanning: Changes in surface topography as a predictor of internal spinal alignment

Introduction

3D non-contact surface scanners capture highly accurate, calibrated images of surface topography for 3D structures. This study sought to establish the efficacy and accuracy of using 3D surface scanning to characterise spinal curvature and sagittal plane contour.

Methods

10 healthy female adults with a mean age of 25 years, (standard deviation: 3.6 years) underwent both MRI and 3D surface scanning (3DSS) (Artec Eva, Artec Group Inc., Luxembourg) while lying in the lateral decubitus position on a rigid substrate. Prior to 3DSS, anatomical landmarks on the spinous processes of each participant were demarcated using stickers attached to the skin surface. Following 3DSS, oil capsules (fiducial markers) were overlaid on the stickers and the subject underwent MRI. MRI stacks were processed to measure the thoracolumbar spinous process locations, providing an anatomical reference. 3D coordinates for the markers (surface stickers and MRI oil capsules) and for the spinous processes mapped the spinal column profiles and were compared to assess the quality of fit between the 3DSS and MRI marker positions.

Results

The RMSE for the polynomials fit to the spinous process, fiducial and surface marker profiles ranged from 0.17–1.15mm for all subjects. The MRI fiducial marker location was well aligned with the spinous process profile in the thoracic and upper lumbar spine for nine of the subjects. Over the 10 subjects, the mean RMSE between the MRI and 3D scan sagittal profiles for all surface markers was 9.8mm (SD 4.2mm). Curvature was well matched for seven of the subjects, with two showing differing curvatures across the lumbar spine due to inconsistent subject positioning.

Conclusion

Comparison of the observed trends for vertebral position measured from MRI and 3DSS, suggested the surface markers may provide a useful method for measuring internal changes in sagittal curvature or skeletal changes.

Anatomy for the Acupuncturist – Facts & Fiction 2: The Chest, Abdomen, and Back

Anatomy knowledge, and the skill to apply it, is arguably the most important facet of safe and competent acupuncture practice. The authors believe that an acupuncturist should always know where the tip of their needle lies with respect to the relevant anatomy so that vital structures can be avoided and so that the intended target for stimulation can be reached. This article reviews clinically relevant anatomy for somatic needling of the chest and abdomen.

Standard reference values of the upper body posture in healthy young female adults in Germany: an observational study

OBJECTIVE

Classifications of posture deviations are only possible compared with standard values. However, standard values have been published for healthy male adults but not for female adults.

DESIGN

Observational study.

SETTING

Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University Frankfurt/Main.

PARTICIPANTS

106healthy female volunteers (21-30 years old; 25.1±2.7 years) were included. Their body weight ranged from 46 to 106 kg (60.3±7.9 kg), the heights from 1.53 to 1.82 m (1.69±0.06 m) and the body mass index from 16.9 kg/m² to 37.6 kg/m² (21.1±2.6 kg/m²).

OUTCOME MEASURES

A three-dimensional back scan was performed to measure the upper back posture in habitual standing. The tolerance ranges and CI were calculated. Group differences were tested by the Wilcoxon Mann-Whitney U test.

RESULTS

In normal posture, the spinal column was marginally twisted to the left, and the vertebrae were marginally rotated to the right. The kyphosis angle is larger than the lumbar angle. Consequently, a more kyphotic posture is observed in the sagittal plane. The habitual posture is slightly scoliotic with a rotational component (scapular depression right, right scapula marginally more dorsally, high state of pelvic right, iliac right further rotated anteriorly).

CONCLUSIONS

Healthy young women have an almost ideally balanced posture with minimal ventral body inclination and a marginal scoliotic deviation. Compared with young males, women show only marginal differences in the upper body posture. These values allow a comparison to other studies, both for control and patient data, and may serve as guideline in both clinical practice and scientific studies.

[Quantification of changes in the external morphology of the back by means of surface topography based on structured light in idiopathic scoliosis in adolescents after a year of treatment with orthopedic corse]

BACKGROUND

To quantify the morphological changes in the surface of the back of adolescents with idiopathic scoliosis as a result of treatment with braces and to correlate them with radiographic changes.

MATERIAL AND METHODS

An analytical, cohort, prospective study on a sample of 31 adolescents with idiopathic scoliosis. We divided them into two groups: eleven treated with braces and twenty without them. Quantification of the deformity was performed on two separate occasions with an interval of one year using three systems: 1) angle of trunk rotation (scoliometer); 2) surface topography; 3) full spine X-rays.

RESULTS

No statistically significant differences were detected between the initial and final assessment of the topographic and radiographic variables in the group with braces. In the untreated group, only in measures with the scoliometer significant differences were registered. A positive correlation was found between the Cobb angle difference of the main curve with two topographic variables that quantify the asymmetry in the axial and coronal plane, respectively.

DISCUSSION

In following patients with scoliosis treated with braces, we should consider and evaluate not only radiographic parameters such as the Cobb angle, but also clinical and topographic parameters that quantify the external deformity of the back, as there is a clinical-radiographic discrepancy amply demonstrated in the literature. The improvement of the external shape of the back is a very important factor for the patient, and can influence a better completion of the orthopedic treatment. In our study, the scoliotic curve and external deformity of the back remained stable during the follow-up period in both treated and untreated patients.

[Rediscussion on the relationshin between back-shu points and twelve meridians]

In current theory, back-shu points are categorized into the bladder meridian of foot-taiyang, resulting in difficulties in interpretation and ineffective guide for clinical acupuncture. The development of acupuncture theory indicates that the relationship between back-shu points and corresponding meridians is established by manifestation and root cause of meridian, and enriched in Qianjin Yifang (A Supplement to Recipes Worth a Thousand Gold), but it has been categorized into the bladder meridian of foot-taiyang since Waitai Miyao Fang (Arcane Essentials from the Imperial Library) and its influences remain so far. After analysis on this academic development and basis of understanding, it is believed that the problems of back-shu points and twelve meridians are presented with how toselect existing theories; it is proposed that the academic value of relationship between back sha points and twelve meridians should be explored and promoted to establish the theory form and structure relationship. As a result, the theory can be completed to guide the clinical treatment.

[Bone-length measurement at low back and its application]

By reviewing some acupuncture literature regarding the settings of bone-length measurement at low back, it was found out that ancient and modern descriptions were not consistent. In China current acupuncture textbook, it was mostly described as "the horizontal distance between inner borders of two scapulas was 6 cun". However, after analysis, it was believed that this setting was not reasonable in the clinical application of acupuncture, and it was agreed with the opinion that "midpoint of inner borders of two scapulas when scapulas are in abduction position" should be taken as bone-length measurement of low back. Besides, a self-made bone-length scale was applied to locate acupoint at low back, which could provide references for its standardized application manipulation.

Soft tissue artefacts of the human back: comparison of the sagittal curvature of the spine measured using skin markers and an open upright MRI

Soft tissue artefact affects the determination of skeletal kinematics. Thus, it is important to know the accuracy and limitations of kinematic parameters determined and modelled based on skin marker data. Here, the curvature angles, as well as the rotations of the lumbar and thoracic segments, of seven healthy subjects were determined in the sagittal plane using a skin marker set and compared to measurements taken in an open upright MRI scanner in order to understand the influence of soft tissue artefact at the back. The mean STA in the flexed compared to the extended positions were 10.2±6.1 mm (lumbar)/9.3±4.2 mm (thoracic) and 10.7±4.8 mm (lumbar)/9.2±4.9 mm (thoracic) respectively. A linear regression of the lumbar and thoracic curvatures between the marker-based measurements and MRI-based measurements resulted in coefficients of determination, R², of 0.552 and 0.385 respectively. Skin marker measurements therefore allow for the assessment of changes in the lumbar and thoracic curvature angles, but the absolute values suffer from uncertainty. Nevertheless, this marker set appears to be suitable for quantifying lumbar and thoracic spinal changes between quasi-static whole body postural changes.

Dietary fat content and fiber type modulate hind gut microbial community and metabolic markers in the pig

Obesity leads to changes in the gut microbial community which contribute to the metabolic dysregulation in obesity. Dietary fat and fiber affect the caloric density of foods. The impact of dietary fat content and fiber type on the microbial community in the hind gut is unknown. Effect of dietary fat level and fiber type on hindgut microbiota and volatile fatty acid (VFA) profiles was investigated. Expression of metabolic marker genes in the gut, adipose tissue and liver was determined. A 2×2 experiment was conducted in pigs fed at two dietary fat levels (5% or 17.5% swine grease) and two fiber types (4% inulin, fermentable fructo-oligosaccharide or 4% solka floc, non-fermentable cellulose). High fat diets (HFD) resulted in a higher (P<0.05) total body weight gain, feed efficiency and back fat accumulation than the low fat diet. Feeding of inulin, but not solka floc, attenuated (P<0.05) the HFD-induced higher body weight gain and fat mass accumulation. Inulin feeding tended to lead to higher total VFA production in the cecum and resulted in a higher (P<0.05) expression of acyl coA oxidase (ACO), a marker of peroxisomal β-oxidation. Inulin feeding also resulted in lower expression of sterol regulatory element binding protein 1c (SREBP-1c), a marker of lipid anabolism. Bacteria community structure characterized by DGGE analysis of PCR amplified 16S rRNA gene fragments showed that inulin feeding resulted in greater bacterial population richness than solka floc feeding. Cluster analysis of pairwise Dice similarity comparisons of the DGGE profiles showed grouping by fiber type but not the level of dietary fat. Canonical correspondence analysis (CCA) of PCR- DGGE profiles showed that inulin feeding negatively correlated with back fat thickness. This study suggests a strong interplay between dietary fat level and fiber type in determining susceptibility to obesity.

Identification of porcine glycogen synthase kinase 3α (GSK-3α) gene and its association with carcass traits

GSK-3 plays an important role on numerous cellular processes involved in the regulation of embryonic development, protein synthesis, glycogen metabolism, inflammatory, mitosis and apoptosis. In this study, we obtained the cDNA and promoter sequences of the porcine GSK-3α gene, analyzed its genomic organization and mapped it to SSC6q12 through comparative mapping method. Moreover, the qRT-PCR analysis revealed that porcine GSK-3α gene was widely expressed in many tissues, and a high expression level was observed in the brain and spleen. In addition, seven single-nucleotide polymorphisms were detected in the promoter region of porcine GSK-3α gene. Association analysis revealed that the GSK-3α Hin1I and MspI polymorphisms both had significant associations (p < 0.05) with loin muscle area, average backfat thickness, thorax-waist fat thickness, and buttock fat thickness. These results provide useful information for further investigation on the function of porcine GSK-3α gene.

Automatic recognition of surface landmarks of anatomical structures of back and posture

Faulty postures, scoliosis and sagittal plane deformities should be detected as early as possible to apply preventive and treatment measures against major clinical consequences. To support documentation of the severity of deformity and diminish x-ray exposures, several solutions utilizing analysis of back surface topography data were introduced. A novel approach to automatic recognition and localization of anatomical landmarks of the human back is presented that may provide more repeatable results and speed up the whole procedure. The algorithm was designed as a two-step process involving a statistical model built upon expert knowledge and analysis of three-dimensional back surface shape data. Voronoi diagram is used to connect mean geometric relations, which provide a first approximation of the positions, with surface curvature distribution, which further guides the recognition process and gives final locations of landmarks. Positions obtained using the developed algorithms are validated with respect to accuracy of manual landmark indication by experts. Preliminary validation proved that the landmarks were localized correctly, with accuracy depending mostly on the characteristics of a given structure. It was concluded that recognition should mainly take into account the shape of the back surface, putting as little emphasis on the statistical approximation as possible.

Non-rigid surface shape registration to monitor change in back surface topography

Measured back surface topographies can be useful to monitor the external manifestation of scoliosis to avoid exposure to large doses of radiation. Manual shape fitting of back surface topographies from successive clinical visits can then be used to detect differences. Automated matching of the measured topographies has been seen as a possible improvement on manual comparisons. Recognizing that two changed surface cannot be expected to be simple rigid replicas of each other, the goal of this research has been to develop a new algorithm based on a non-rigid surface matching algorithm, suited to matching the surfaces into same reference frame while also estimating the parameters of the scoliosis deformities, and eliminating noise due to normal body change caused by growth. Back surface topography data from laser optical scanning have been automatically matched by a least squares non-rigid matching algorithm. The algorithm includes new parameters able to model shape changes caused by normal growth and scoliosis deformation. This non-rigid matching algorithm returned r.m.s. values for surface closeness which were improved by at least 10% over rigid matching. Experiments on various scoliosis data demonstrate that the non-rigid matching algorithm is able to accurately match the surfaces while simultaneously extracting parameters representing patient shape change. The non-rigid algorithm has proven to be an improvement on the classical rigid surface matching approach which allows positional fit rather than shape fit. Measured back surface topographies can be closely matched to monitor the external manifestation of scoliosis.

Optimal inertial sensor location for ambulatory measurement of trunk inclination

Trunk inclination (TI) is used often to quantify back loading in ergonomic workplace evaluation. The aim of the present study was to determine whether TI can be obtained using a single inertial sensor (IS) on the back, and to determine the optimal IS location on the back for the estimation of TI. Gold standard TI, the angle between the vertical and the line connecting the L5/S1 joint and the trunk centre of mass, was measured using an optoelectronic system. Ten subjects performed experimental trials, each consisting of a symmetric and an asymmetric lifting task, and of a left-right lateral flexion movement. Trials were repeated and, in between trials, the IS was shifted in small steps from a location on the thorax towards a location on the sacrum. Optimal IS location was defined as the IS location with minimum root-mean-square (RMS) error between the gold standard TI and the IS TI. Averaged over subjects, the optimal IS location for symmetric and asymmetric lifting was at about 25% of the distance from the midpoint between the posterior superior iliac spines (MPSIS) to the C7 spinous process. The RMS error at this location, averaged over subjects, was 4.6+/-2.9 degrees. For the left-right lateral flexion task, the optimal IS location was at about 30% of the MPSIS to C7 distance. Because in most activities of daily living, pure lateral flexion does not occur often, it is recommended place the IS at 25% of the distance from the MPSIS to C7.

The virtual haptic back: a simulation for training in palpatory diagnosis

BACKGROUND

Models and simulations are finding increased roles in medical education. The Virtual Haptic Back (VHB) is a virtual reality simulation of the mechanical properties of the human back designed as an aid to teaching clinical palpatory diagnosis.

METHODS

Eighty-nine first year medical students of the Ohio University College of Osteopathic Medicine carried out six, 15-minute practice sessions with the VHB, plus tests before and after the sessions in order to monitor progress in identifying regions of simulated abnormal tissue compliance. Students palpated with two digits, fingers or thumbs, by placing them in gimbaled thimbles at the ends of PHANToM 3.0(R) haptic interface arms. The interface simulated the contours and compliance of the back surface by the action of electric motors. The motors limited the compression of the virtual tissues induced by the palpating fingers, by generating counterforces. Users could see the position of their fingers with respect to the back on a video monitor just behind the plane of the haptic back. The abnormal region varied randomly among 12 locations between trials. During the practice sessions student users received immediate feedback following each trial, indicating either a correct choice or the actual location of the abnormality if an incorrect choice had been made. This allowed the user to feel the actual abnormality before going on to the next trial. Changes in accuracy, speed and Weber fraction across practice sessions were analyzed using a repeated measures analysis of variance.

RESULTS

Students improved in accuracy and speed of diagnosis with practice. The smallest difference in simulated tissue compliance users were able to detect improved from 28% (SD = 9.5%) to 14% (SD = 4.4%) during the practice sessions while average detection time decreased from 39 (SD = 19.8) to 17 (SD = 11.7) seconds. When asked in anonymous evaluation questionnaires if they judged the VHB practice to be helpful to them in the clinical palpation and manual medicine laboratory, 41% said yes, 51% said maybe, and 8% said no.

CONCLUSION

The VHB has potential value as a teaching aid for students in the initial phases of learning palpatory diagnosis.

Automated segmentation of the quadratus lumborum muscle from magnetic resonance images using a hybrid atlas based - geodesic active contour scheme

This study presents a novel method for the automatic segmentation of the quadratus lumborum (QL) muscle from axial magnetic resonance (MR) images using a hybrid scheme incorporating the use of non-rigid registration with probabilistic atlases (PAs) and geodesic active contours (GACs). The scheme was evaluated on an MR database of 7mm axial images of the lumbar spine from 20 subjects (fast bowlers and athletic controls). This scheme involved several steps, including (i) image pre-processing, (ii) generation of PAs for the QL, psoas (PS) and erector spinae+multifidus (ES+MT) muscles and (iii) segmentation, using 3D GACs initialized and constrained by the propagation of the PAs using non-rigid registration. Pre-processing of the images involved bias field correction based on local entropy minimization with a bicubic spline model and a reverse diffusion interpolation algorithm to increase the slice resolution to 0.98 x 0.98 x 1.75mm. The processed images were then registered (affine and non-rigid) and used to generate an average atlas. The PAs for the QL, PS and ES+MT were then generated by propagation of manual segmentations. These atlases were further analysed with specialised filtering to constrain the QL segmentation from adjacent non-muscle tissues (kidney, fat). This information was then used in 3D GACs to obtain the final segmentation of the QL. The automatic segmentation results were compared with the manual segmentations using the Dice similarity metric (DSC), with a median DSC for the right and left QL muscles of 0.78 (mean = 0.77, sd=0.07) and 0.75 (mean =0.74, sd=0.07), respectively.

Diagnosis and treatment of back pain

Back pain is one of the most prevalent medical problems seen by primary care physicians, and it costs the American public billions of dollars each year. Yet, accurate diagnosis and successful treatment remain elusive. Medical imaging plays an increasing role in helping to diagnose back pain causes, pinpoint treatments and study how back pain might be addressed more adequately.

Back muscles biometry in adolescent idiopathic scoliosis

BACKGROUND CONTEXT

Many studies have been devoted to the role of back muscle activity in the development of scoliosis. While an imbalance in the electromyographic (EMG) activity has often been detected at the skin surface, very little information is available on the mechanisms by which such an imbalance could take place. To gain insight into those mechanisms, an important step could be the collection of anatomical data on the volume of the erector spinae muscle on both sides of the spine as well as on the skin and subcutaneous fat (skinfold) thickness separating those muscles from the body surface. For this purpose, the use of magnetic resonance (MR) imaging is appropriate.

PURPOSE

To collect anatomical information on the erector spinae muscles and skinfold thickness along the spinal deviations of scoliotic patients.

STUDY DESIGN

In an observational retrospective study, MR images of scoliotic patients treated in a pediatric hospital in the last 5 years were analyzed.

PATIENT SAMPLE

Images were obtained from adolescent idiopathic scoliosis patients.

METHODS

For 15 patients (Group I), three clinical acquisition protocols were used. Five investigators were asked to grade the contrast of the images obtained with each protocol. All the assessments were carried on the same monitor without any change in its settings. For the MR sequence providing the best contrast, 25 fully imaged scoliotic deviations were obtained from 17 patients (Group II). A manual segmentation with an image processing software package was done on the erector spinae muscle on both sides of the spine on each of the available images in order to determine their volume. Skinfold was also measured; first at regular intervals from C7 to L3 over the erector spinae muscle and then at sites centered over the apex of each curve.

RESULTS

For Group I, the spin echo (SE-T1) was found to provide the best contrast to identify the contour of individual muscle. With this sequence, the analysis of the fully imaged scoliotic curves (Group II) revealed that back muscle volume was found larger 14 times on the concave side and 11 times on the convex one. When the length of each curve was normalized and then divided into three equal regions, muscle volume was larger 11 times at the apex (6 times on concave side), 7 times above and 7 times below (4 times on the concave side for both positions). From C7 to L3, the mean skinfold thickness of each patient ranged from 7.3 mm to 16.3 mm. On average, this thickness was <10 mm between T3 and T12 but became larger at L3 level. At the apex of each scoliotic deviation, skinfold thickness was always larger on the concave side, and the difference decreased progressively as the distance from the apex increased.

CONCLUSION

A larger back muscle volume in adolescent idiopathic scoliosis patients was slightly more frequent on the concave than on the convex side. The differences were more frequent at the apex of the curve. Skinfold thickness was always greater on the concave side at the apex region.

Skin to posterior lumbar epidural space distance

OBJECTIVE

To measure the clinically relevant skin to posterior lumbar epidural space distance in adult surgical patients and to correlate this distance with the patient physical factors to construct a model for the prediction of this distance using the correlation.

DESIGN

A cross-sectional study.

PLACE AND DURATION OF STUDY

Department of Anaesthesiology, P.A.F Hospital, Islamabad over a period of 18 months from 1st January 2003 to 30th June 2004.

PATIENTS AND METHODS

The study was carried out in 100 patients divided into three groups, who were scheduled for different surgical procedures. Group-I consisted of female patients scheduled for lower segment caesarian section (L.S.C.S); group-II adult non-pregnant females undergoing elective surgery and group-III adult males undergoing different surgical procedures. Epidural anaesthesia was given, using loss of resistance (LOR) technique, and skin to posterior epidural space was measured.

RESULTS

The mean skin to posterior lumbar epidural space distance was found to be 3.8+/-0.5 cm in group-I, 3.76+/-0.7 cm in group-II and 4.0+/-0.5 cm in group-III. Skin to posterior epidural space distance correlates best with weight of the patient.

CONCLUSION

Posterior lumbar skin to epidural space distance has been found to be less than what is normal in rest of the world. These results may be used as a guideline for performing successful epidural blocks in Pakistani population. A reliable model using patient physical factors to predict skin to posterior epidural space distance could not be constructed.

Homologies of thelongissimus,iliocostalis, and hypaxial muscles in the anterior presacral region of extant diapsida

Homologies of muscles of the m. longissimus and m. iliocostalis groups in the dorsal and cervical regions, as well as those of the subvertebral muscles and mm. intercostales externi that continue from the dorsal into the cervical regions, in extant Diapsida are proposed based on detailed dissections and published accounts of lepidosaurs, crocodylians, and birds. The morphology of tendons and innervation patterns suggest that the avian "m. iliocostalis" in the dorsal region include the homologs of both m. longissimus and m. iliocostalis in non-avian diapsids. The conserved nature of the morphology of tendons in palaeognath birds also revealed that the avian mm. intertransversarii in the cervical region consist of muscles of the both m. longissimus and m. iliocostalis groups despite having been treated as a single series of muscles, and thus are not homologous with muscles of the same name in Lepidosauria or Crocodylia. The avian mm. inclusi that lie medial to mm. intertransversarii are homologous with mm. intercostales externi in Lepidosauria and mm. intercostales externi and m. scalenus combined in Crocodylia. Innervation patterns suggest that a muscle ("m. iliocostalis capitis") connecting the atlas rib and occiput in Crocodylia includes contributions from the subvertebral layer and m. cucullaris complex, and possibly m. iliocostalis as well. The present findings may serve as a basis for revising the currently used avian nomenclature so that it will reflect homologies of muscles with their non-avian counterparts.

The membranous layer of superficial fascia: evidence for its widespread distribution in the body

A discrete membranous layer, "stratum membranosum", in human subcutaneous tissue is classically described as confined to the lower anterior abdominal wall and perineum and referred to as Scarpa's and Colles' fasciae, respectively. Evidence for its existence elsewhere in the body is scanty and therefore the present study was undertaken. Dissection of six embalmed adult cadavers, along with ultrasound imaging on four living subjects, were carried out to determine the existence, topography, and thickness of the membranous layer of superficial fascia in different regions of the body. In all six cadavers, a continuous layer of fibrous membrane in the superficial fascia was found consistently in all the dissected regions of the body and was also confirmed by ultrasonography. The arrangement and thickness of this membranous layer varied according to body region, body surface, and gender. It was thicker in the lower than in the upper extremity, on the posterior than anterior aspect of the body, and in females than in males. The mean thickness of the membranous layer ranged from 39 to 189 mum, being thickest in the leg and thinnest over the dorsum of the hand. The membranous layer was observed to have two or even three components in regions such as the breast, back, thigh, and arm and was seen to split, forming special compartments around subcutaneous major veins of upper and lower extremities, with fibrous septa extending to attach to the vessel wall. Functionally, the membranous superficial fascia may play a role in the integrity of the skin and support for subcutaneous structures particularly veins, by ensuring their patency. Understanding the topographic anatomy of this fascial layer may help explain body-contour deformities and provide the anatomic basis for surgical correction.

Surgical technique and anatomic study of latissimus dorsi and teres major transfers

BACKGROUND

Combined latissimus dorsi and teres major musculotendinous transfer has been described for the treatment of massive rotator cuff deficits. The procedure is technically complex because of the proximity of the radial nerve, the axillary nerve and its posterior branches, and the neurovascular bundles to the muscles. The purpose of the present cadaveric study was to examine surgically relevant relationships for latissimus dorsi and teres major tendon transfers.

METHODS

Twelve cadaveric shoulder girdles were dissected, and the latissimus dorsi, the teres major, and the posterior cord of the brachial plexus and its branches were identified. The relationships between the tendons and local neurologic structures were measured during various steps of the latissimus dorsi/teres major transfer procedure. The effect of humeral rotation on the exposure of the latissimus dorsi and teres major tendons through the posterior approach was quantified, and relevant surgical landmarks were described.

RESULTS

The radial nerve passed directly anterior to the tendons at an average of 2.9 cm medial to the superior aspect and 2.3 cm medial to the inferior aspect of the humeral insertions. From the posterior axillary approach, maximal internal rotation facilitated exposure for tenotomy by delivering the tendon insertions on the humerus into the surgical field. During axial mobilization of the musculotendinous units, the neurovascular pedicles to the latissimus dorsi and teres major were identified at an average of 13.1 and 7.4 cm axial to the humeral insertions, respectively. The posterior branch of the axillary nerve was noted to cross superficially over the transferred tendons as they were tunneled under the posterior deltoid.

CONCLUSIONS

Multiple steps of the combined latissimus dorsi and teres major musculotendinous transfer place local neurologic structures at risk. These steps include tendon release, musculotendinous axial mobilization, and tendon tunneling in the plane between the infraspinatus-teres minor and the posterior deltoid. We have quantified and described the relationship of the axillary and radial nerves to the tendons during tenotomy, the distance from the tendons' insertions to their neurovascular bundle that must be identified during axial mobilization, and the course of the posterior branch of the axillary nerve in relation to the tunneled path of the tendons.

CLINICAL RELEVANCE

The present study provides important anatomic findings for the safe mobilization and transfer of the latissimus dorsi and teres major tendons during the surgical treatment of irreparable rotator cuff tears.

Does reaching the back reflect the actual internal rotation of the shoulder?

To clarify the relationship between the vertebral level reached by the thumb and the internal rotation angle of the humerus, 7 shoulders in healthy volunteers were examined by use of an electromagnetic tracking device. Measurements were repeated in the hanging-arm position with the thumb pointing anteriorly and at the buttock, sacrum, and each vertebral level up to T6. From the hanging-arm position to the buttock, 54.3% of internal rotation occurred (mean, 39.8 degrees ), and from the buttock to the sacrum, 11.7% occurred (mean, 8.6 degrees ). In total, 66% of internal rotation occurred from the hanging-arm position to the sacrum. Above the sacrum, the contribution of elbow flexion to the level of the vertebral spine became much greater, and internal rotation of the shoulder did not change significantly above the T12 level. We recommend that the level of the thumb below the buttock be subdivided for more accurate assessment of internal rotation.

Iliolumbar membrane, a newly recognised structure in the back

Despite intensive research in the anatomical sciences for the last two centuries, some structures of the human body still remain controversial or incompletely described. We describe a new membranous fascial anatomical entity, which we refer to as the iliolumbar membrane (ILM). During the 2004-2005 academic semesters at the American University of the Caribbean School of Medicine we dissected 40 human cadavers fixed in formalin-alcohol-phenol solution. Iliolumbar membrane is a thick connective tissue structure, deep to the skin, originating from the fibres of the thoracolumbar fascia at the lateral border of the erector spinae. It runs inferior to the superior border of the iliac crest, lateral to the posterior superior iliac spine, overlying the iliac crest at the level of the 4th lumbar vertebra. Iliolumbar membrane terminates within subcutaneous fat, where it divides into multiple layers. All cadavers showed considerable variation in the blending of the membrane's multiple layers with the subcutaneous fat. However, all specimens consistently showed a uniform appearance of ILM at the point of origin. Iliolumbar membrane could be demonstrated objectively by ultrasound examination with a frequency of 7.5 MHz and also with a Stryker endoscope. A hypothesis is put forth, conjecturing that this new structure may have relevance in creating a natural barrier between the musculature of the back and the muscles of the gluteal region, similar to Scarpa's fascia of the anterior abdominal wall.

Surface alignment to unmask scoliotic deformity in surface topography

Comparisons of back surface topography to monitor scoliosis are hampered by shape change due to other causes, primarily stance variations. The aim is to extract changes due only to the scoliosis from the observed changes. Surface (back) topography data were derived from 2 patients measured repeatedly (10x) at a single visit and from 45 patients measured at routine clinical visits. The measured back shapes were aligned to obtain the position of closest fit using a mathematical technique. The shape similarities were then quantified with a closeness-of-fit index. The similarity indices from the alignments were used to estimate noise factors due to postural variation, relative to typical patient change. Surface alignment has also been trialled using models with predictable topographic changes to determine whether the noise sources can be modelled. The values of the root-mean-square of the residual surface differences at all measured points after mathematical back shape alignment were used as a surface similarity index. The magnitude of this index for the repeatedly measured back shapes indicates the back shape variation due to stance, and has been compared with the variation found in normal patients. The similarity index has also been examined for cases both with and without modelled changes to estimate the effectiveness of stance modelling. The noise due to stance change was indicated by a surface similarity index which averaged 2.0 mm; the index for backs measured at routine visits averaged 3.5 mm. It was concluded that noise due to stance is significant and deserves to be recognised, in the comparison of back surfaces in three-dimensions. There is evidence that changes due to noise can be modelled.

Iliocostalis muscles in three mammals (dolphin, goat and human): Their identification, structure and innervation

Iliocostalis (IC) muscles were studied in four dolphin embryos, three goat embryos and four Japanese adult cadavers through macroscopic dissection. The IC muscles of the dolphin were located on the lateral aspect of the trunk and displayed an intercostal arrangement. In contrast, the IC muscles in both the goat and human showed a double-layered architecture formed by a multisegmental muscle-tendon complex and were located on the lateral and medial sides of the costal angle, respectively. Generally, the nerve to the iliocostalis (NIC) in the dolphin and goat did not form a common trunk with the nerve to the longissimus on the epaxial plane, whereas in humans the NIC ran parallel to the nerve to the longissimus part of the way. The individual NIC ran caudolaterally, innervating the one lower (caudal) metameric division of the IC muscle in the dolphin and piercing the fascia of the IC muscles at a point in the next caudal intercostal level in the goat and human. In the upper thoracic part of the goat and human, the caudal shift of innervation was obscured, where the IC muscles were close to the vertebrae. The course of the NIC was closely related to that of the lateral cutaneous branch. The present study shows that the NIC is commonly destined for the one lower intercostal level among the three mammalian species, with their respective IC muscles having distinctly different structural complexity.

[<< Reverse >> latissimus dorsi musculocutaneous flap: anatomic study of the secondary pedicles]

PURPOSE

The latissimus dorsi flap based on the secondary segmental vessels, wich is termed << reverse >> or << distally based >> latissimus dorsi flap, has been used to repair major thoraco-lumbar defects, to close myelomeningoceles and to reconstruct congenital diaphragmatic absences. The arc of flap rotation is markedly restricted because the blood supply is segmental. It is the most important factor that limits the flap mobility and so restricts its use. The authors report an anatomic study of these secondary pedicles in order to improve the flap dissection and to extend the arc of flap rotation.

MATERIAL AND METHOD

The precise location of the secondary pedicles of the flap was determined by 24 anatomic dissections.

RESULTS

The latissimus dorsi has 3, 4 or 5 secondary pedicles respectively in 50%, 25% and 25% of cases in the study. These pedicles take origin from the dorsal branches of the posterior intercostal arteries of the 7th, 8th, 9th, 10th and 11th intercostal spaces.

CONCLUSION

The number of secondary pedicles is not constant. The entire flap can be safely based on 2 secondary pedicles when the latissimus dorsi muscle has 3 secondary pedicles. When this muscle has 4 or 5 secondary pedicles, the entire flap should be at least based on 3 secondary pedicles, particularly if the skin island is very far from the origin of these vessels.

Site-specific protective effect of broad-spectrum sunscreen on nevus development among white schoolchildren in a randomized trial

BACKGROUND

Melanocytic nevus density is a strong risk factor for cutaneous malignant melanoma. Reducing the number of nevi in children may reduce the risk of their developing melanoma as adults.

OBJECTIVE

We sought to assess the effect of sunscreen use on nevus development by anatomic sites and by nevi of different sizes for white schoolchildren in a randomized trial.

METHODS

We compared the new nevus count between the sunscreen intervention group (n = 145) and the control group (n = 164) by anatomic site.

RESULTS

Children randomized to the sunscreen group had significantly fewer new nevi on the trunk than children in the control group. The differences were more pronounced among the freckled children than children with no freckles.

LIMITATIONS

Potential limitations to this study include relatively small numbers of enrolled children, and a follow-up period of only 3 years.

CONCLUSION

Sunscreen use attenuated new nevus development on intermittently sun-exposed body sites for white schoolchildren, particularly among the freckled children.

In vivo measurement of lower back deformations with Fourier-transform profilometry

Through the variation of their cross sections, the in vivo response of lower back muscles to low loading in an upright seated posture is explored by the Fourier-transform profilometry technique. The maximization of its sensitivity allows us to reach an adequate resolution for the evaluation of low-back displacements. Refinements of the fringe pattern analysis permit the minimization of errors. The experiments show an asymmetric distribution of the displacement during head rotation movements. Significant contribution of the lower back to grasping exertions is also observed. These results are thought to be useful for early defect detection in the lower back.

Elevator muscle of the tendon of latissimus dorsi muscle

Muscular dispositions in the axilla acquire importance under certain surgical procedures that involve the axillary artery ligature. These supernumerary muscles make the approach to the axillary fossa and their content difficult. We dissected 108 formalized corpses from adult male individuals. The specimens belong to the topographic Anatomy Unit of the Faculty of Medicine, Universidad de La Frontera, Chile. In all dissections, a rare and infrequent muscular variation attributed to the presence of a elevator muscle at the dorsal part of the latissimus muscle on the right upper limb from an adult individual was found. This muscle was fusiform and originated at the coracoid process by a short tendon of cylindrical form inserted in the dorsal superior part of the tendon of the latissimus dorsi muscle. Muscular belly and tendons of origin and insertion were closely related to the brachial plexus and the axillar vessels that they crossed.

Lymphatic drainage of the skin

A successful sentinel lymph node biopsy (SLNB) in melanoma patients requires an accurate map of the pattern of lymphatic drainage from the primary site. Lymphoscintigraphy (LS) can provide such a map. LS needs an understanding of lymphatic physiology, an appropriate small-particle radiocolloid, high-resolution collimators, and imaging protocols that detect all sentinel nodes (SNs). Patterns of lymphatic drainage from the skin are not clinically predictable. Unexpected drainage has been found from the skin of the back to SNs in the triangular intermuscular space (TIS) and the paraaortic, paravertebral, and retroperitoneal areas. It can also occur from the base of the neck up to nodes in the occipital or upper cervical areas or from the scalp down to nodes at the neck base, bypassing many node groups. Upper limb drainage can be to SNs above the axilla. Interval nodes not uncommonly can be SNs, especially on the trunk. Lymphatic drainage may involve SNs in multiple nodal fields, and drainage across the midline of the body is quite common. Because micrometastatic disease can be present in any SN regardless of its location, all true SNs must be biopsied. LS is an important first step to ensure this goal is achieved.

[Anatomy of latissimus dorsi and its clinical application]

OBJECTIVE

To investigate the feasibility of segmentation of latissimus dorsi on the basis of anatomy and electrophysiology.

METHODS

Ten cadaveric latissimus dorsi was dissected according to the blood supply, nerve innervation. Electromyelogram (EMG) of latissimus dorsi of 13 healthy persons was recorded with superficial electrode plate in the motion of shoulder joint. The results of record were managed with statistic methods. Ten patients(including reconstruction of breast and repair of scar on elbow joint and on chest wall) were treated with the lateral inferior myocutaneous island flap.

RESULTS

According to the medial and lateral vasculonervous branches, latissimus dorsi can be divided into the medial superior and lateral inferior segments. The clinical application of the segment achieved good results in reconstructing breast and in repairing scars on elbow and on chest wall.

CONCLUSION

Latissimus dorsi can be divided into two segments and applied separately. The lateral inferior segment is more useful in shoulder motion.

Genetic algorithm-neural network estimation of cobb angle from torso asymmetry in scoliosis

Scoliosis severity, measured by the Cobb angle, was estimated by artificial neural network from indices of torso surface asymmetry using a genetic algorithm to select the optimal set of input torso indices. Estimates of the Cobb angle were accurate within 5 degrees in two-thirds, and within 10 degrees in six-sevenths, of a test set of 115 scans of 48 scoliosis patients, showing promise for future longitudinal studies to detect scoliosis progression without use of X-rays.

Effect of conformational aspects on the movement of the equine back

The relationship between structure and function is important in the judgement of the horse. Twenty sound riding horses walked and trotted on a treadmill. The movement of the backs of each of the horses was measured using a commercially available movement analysis system. Morphometric, spatiotemporal and kinematic information were correlated to investigate the effect of conformation on movement. Taller and heavier horses seem to have longer thoracic and lumbar backs, and are wider at the pelvis. Horses with longer strides extended and flexed their backs in the caudal saddle region to a greater extent at the walk, but not the trot. Horses with greater angle of L5 tend to extend and flex this region of the back more. At the walk and trot, a long thoracic back results in greater lumbar lateral bending. A negative relationship was found between the curvature of mid-thoracic back and the amount of lateral bending of L1 and L3 and axial rotation of the pelvis at the trot. There are clear relationships between back conformation and movement that may be important to the orthopaedic health of the horse. Further understanding of the relationships between conformation, movement and injury may provide an objective basis for the evaluation of future performance and soundness.

Lumbar hernia: anatomical route assessed by computed tomography

Lumbar hernia is classically described as arising from the superior (Grynfeltt's) lumbar triangle or the inferior (Jean-Louis Petit's) lumbar triangle. The present anatomical study based on a computed tomography examination performed in a patient with lumbar hernia, has led to the suggestion that lumbar hernias cross the lumbar wall through a musculoaponeurotic tunnel, whose deep and superficial openings are the superior and inferior lumbar triangles, respectively.

User friendly computer profilometry

Portable optical profilometer for measurement and analysis of the human back shape has been developed. The driving user friendly software includes correction of distortion of the observation lens, data calibration, three-dimensional Z-axis rotation of the patient normalizing his position, calculus of the curvature map (second derivative), and precise indication of different characteristic points of the back including the spinous processes line. This instrument enables the examination of the back in both erected and bent positions.

3D back shape in normal young adults

In today's climate of evidence based medicine, there is an increasing emphasis on objective assessment to monitor treatment effectiveness. Although spinal posture and back shape are commonly assessed by clinicians, current practice is based on subjective findings and unreliable objective tools. Numerous management protocols aim to improve both posture and shape, however data related to normal back shape is quite scarce. The aim of this study was to investigate normal back shape in young adults, in order to produce normative values against which deformity could be defined. The Integrated Shape Imaging System (ISIS) was used to measure the three-dimensional back shape. A convenience sample of 48 normal adults, aged 18-28 volunteered to participate in this study. A small minority of individuals showed no curve (8%), 55% showed a single curve and the rest showed a double one. Right spinal asymmetry was more frequent than the left (77% to 52%). Mean values and 95% confidence intervals were 14.1 degrees (11.7 degrees-16.5 degrees) for upper Lateral asymmetry, 5.6 degrees (3.3 degrees - 7.9 degrees) for lower lateral asymmetry, 24.9mm (20.6mm -29.2mm) for thoracic kyphosis and 14.9mm (12.5mm -17.2mm) for lumbar lordosis. Increasing upper lateral asymmetry correlated with decreasing thoracic kyphosis (p=0.01). Maximum skin surface angle correlated positively with only upper lateral asymmetry (p<0.0001). Similar topographical interrelationships have been demonstrated in scoliosis. It is important that clinicians in relevant disciplines objectively assess all three dimensions of back shape, as our research shows that changes in one plane are associated with changes in the other two planes.

3-D measurement of posture and back shape using a low cost, portable system--a reliability study

The reliability and accuracy in the measurement of landmark points using a 3-D digitizer on a static back phantom are reported. The results show the systems clinical reliability as a low cost, portable and flexible method for recording back posture. Consistent results are demonstrated for a single measurer and good agreement was found between two measurers. Few intrinsic errors were found in the devices performance.

Sectional neuroanatomy of the lower limb II: leg and foot

The authors have produced a pair of articles that can be used to rapidly identify back, hip, and lower limb muscles and their innervation(s). This article presents the motor and sensory innervation of the lower limb by color-coding structures to match their peripheral nerves. It provides a companion summary table that allows prediction of unique patterns of denervation from 12 lesions sites.

Estimation of spinal deformity in scoliosis from torso surface cross sections

STUDY DESIGN

Correlation of torso scan and three-dimensional radiographic data in 65 scans of 40 subjects.

OBJECTIVES

To assess whether full-torso surface laser scan images can be effectively used to estimate spinal deformity with the aid of an artificial neural network.

SUMMARY OF BACKGROUND DATA

Quantification of torso surface asymmetry may aid diagnosis and monitoring of scoliosis and thereby minimize the use of radiographs. Artificial neural networks are computing tools designed to relate input and output data when the form of the relation is unknown.

METHODS

A three-dimensional torso scan taken concurrently with a pair of radiographs was used to generate an integrated three-dimensional model of the spine and torso surface. Sixty-five scan-radiograph pairs were generated during 18 months in 40 patients (Cobb angles 0-58 degrees ): 34 patients with adolescent idiopathic scoliosis and six with juvenile scoliosis. Sixteen (25%) were randomly selected for testing and the remainder (n = 49) used to train the artificial neural network. Contours were cut through the torso model at each vertebral level, and the line joining the centroids of area of the torso contours was generated. Lateral deviations and angles of curvature of this line, and the relative rotations of the principal axes of each contour were computed. Artificial neural network estimations of maximal computer Cobb angle were made.

RESULTS

Torso-spine correlations were generally weak (r < 0.5), although the range of torso rotation related moderately well to the maximal Cobb angle (r = 0.64). Deformity of the torso centroid line was minimal despite significant spinal deformity in the patients studied. Despite these limitations and the small data set, the artificial neural network estimated the maximal Cobb angle within 6 degrees in 63% of the test data set and was able to distinguish a Cobb angle greater than 30 degrees with a sensitivity of 1.0 and specificity of 0.75.

CONCLUSIONS

Neural-network analysis of full-torso scan imaging shows promise to accurately estimate scoliotic spinal deformity in a variety of patients.

The representation of the back in idiomatic expressions--do idioms value the body?

OBJECTIVE

Whilst investigating the influence of patients' representations on the impact of teaching in the back school, we took an interest in 1) the place of the back in the French idioms referring to the body; and 2) the meaning these idioms convey about the back.

METHODS

The idioms including body part terms were sought on the basis of a compilation of French idioms; it has to be noted that such a compilation, however excellent it may be, can only offer a partial view of lay conversation. Occurrence of body parts and of their connotations were assessed. Idioms were classified as positive, negative or neutral, keeping in mind the difficulties of a strict classification in such a field. Drawings were then performed on the basis of the results of the descriptive analysis.

RESULTS

Globally, idiomatic expressions offer a rather negative picture of the body or at least suggest that the body is prominently used to express negative ideas and emotions. This is particularly striking for the idioms associated with the back.

CONCLUSION

The analysis of idioms referring to the body allows us to 'see with our own eyes' another aspect of the representations of the body and the back, as they are conveyed in the French language.

Timing of activation of the erector spinae and hamstrings during a trunk flexion and extension task

STUDY DESIGN

Timing of activation of the hamstrings and erector spinae was assessed using surface electromyography.

OBJECTIVES

To investigate the influence of posture and movement speed during trunk flexion-extension on the flexion-relaxation response and trunk muscle activation patterns.

SUMMARY OF BACKGROUND DATA

The literature contains numerous reports on coactivity and synergistic behavior of major muscle groups during trunk flexion-extension. There are few reports on the timing of muscle activation.

METHODS

Six subjects were recruited for a training session and six biweekly test sessions. Ten surface electromyogram electrodes and a lordosimeter were used to record timing of lumbar motion and muscle recruitment in the hamstrings and at four sites in the thoracolumbar region. A 3 x 2 within-subject factorial design was used to test the effects of posture and speed on activation patterns.

RESULTS

Patterns of muscle activation were found to be dependent on posture and the direction of movement. The flexion-relaxation response was pervasive in the lumbar region but was less consistent at the T9 and hamstring sites. Significant differences in the delay between electromyogram activation and lumbar motion were found for the standing postures at initiation of extension, in which activation progressed in the caudad-to-cephalad direction.

CONCLUSIONS

The flexion-relaxation response is ubiquitous in the lumbar erector spinae and is present in the hamstrings and lower thoracic erector spinae, although not consistently in all subjects. In standing, timing of activation differed significantly by site in extension but not in flexion. Muscle activation patterns and flexion-relaxation were consistent over six biweekly test sessions.

Genome-wide scan for body composition in pigs reveals important role of imprinting

The role of imprinting in body composition was investigated in an experimental cross between Chinese Meishan pigs and commercial Dutch pigs. A whole-genome scan revealed significant evidence for five quantitative trait loci (QTL) affecting body composition, of which four were imprinted. Imprinting was tested with a statistical model that separated the expression of paternally and maternally inherited alleles. For back fat thickness, a paternally expressed QTL was found on Sus scrofa chromosome 2 (SSC2), and a Mendelian-expressed QTL was found on SSC7. In the same region of SSC7, a maternally expressed QTL affecting muscle depth was found. Chromosome 6 harbored a maternally expressed QTL on the short arm and a paternally expressed QTL on the long arm, both affecting intramuscular fat content. The individual QTL explained from 2% up to 10% of the phenotypic variance. The known homologies to human and mouse did not reveal positional candidate genes. This study demonstrates that testing for imprinting should become a standard procedure to unravel the genetic control of multifactorial traits.

Variability in three-dimensional measurements of back contour with raster stereography in normal subjects

Forty normal children with a mean age of 9.1 years were investigated by using a Quantec Spinal Image System (QSIS). The QSIS uses computerized raster stereography technology to acquire three-dimensional measurements of back contour. Within a 95-percentile confidence interval (a) coronal-plane QSIS angles ranged from 0.05 to 2.36 degrees; (b) transverse-plane QSIS angles ranged from 0.03 to 1.96 degrees; and (c) sagittal-plane QSIS angles ranged from 36.8 to 44.8 degrees. Trunk-alignment deviation ranged from 3.51 to 7.45 mm within a 95-percentile confidence interval. An intraobserver standard deviation of +/-4.2 degrees was noted across all angular metrics. Normal ranges of QSIS-determined values for a population of 40 children without clinical evidence of pathology are reported.

Relationship between muscle fiber composition and functional capacity of back muscles in healthy subjects and patients with back pain

Back muscles are important to the stability of the lumbar spine. Muscle fiber composition may give some indication of the functional capacity of these muscles. This review explores the relationship between muscle fiber composition and functional capacity of back muscles. The reference values for the type and size of the muscle fibers found in the back musculature of healthy subjects and patients with back pain are also presented. A high percentage of type I fibers, which are larger in size than type II fibers, has been found in back muscles at the thoracic and lumbar levels. This is in accordance with the postural function of these muscles. The diameter of type II fibers is smaller in females than males, which may partly explain the lesser strength and greater endurance capacity of back muscles in females. Due to the limited amount of pertinent data, no conclusive evidence is available regarding age-related changes in muscle fiber composition in the musculature of the back. In patients with lumbar disorders, pathological changes and selective atrophy of type II fibers are seen, and these can be changed with adequate exercises. Further research is suggested to address issues related to gender, age, back pain, and exercise and their effects on the apparent back muscle fiber composition.

Quantification of cosmesis for patients affected by adolescent idiopathic scoliosis

The aim of this study was to quantify cosmesis for patients affected by adolescent idiopathic scoliosis. Eight nonmedical judges were asked to examine photographs of 40 patients with adolescent idiopathic scoliosis, and to score the cosmesis of their backs without any information. Various parameters were measured from radiographs, Moiré topographies, and physical measurements of patients, and these were compared with the cosmetic scores of the judges. The judges' scoring proved to be reliable. The cosmetic scores showed a significant correlation with the Cobb angle, hump severity, asymmetry of the waist line, circumference of the chest, and obesity. Multivariate analysis produced equations to calculate the cosmetic score for the back. This equation is thought to have a useful clinical application.

Comparative myology of the forelimb of squirrels (Sciuridae)

The musculature of the shoulder, arm, and forearm was studied in 19 genera of squirrels, representing the Pteromyinae (flying squirrels) and all 7 tribes of the Sciurinae (tree and ground squirrels). The objective was to locate derived anatomical features of functional or phylogenetic significance and to determine how much morphological variation underlies the diverse locomotor behavior of squirrels, which includes terrestrial and arboreal bounding, climbing, digging, and gliding. The fossil evidence suggests that arboreality is primitive for squirrels, and in fact tree squirrels appear to represent the primitive sciurid morphology. Ground squirrels are less uniform and exhibit a few derived features, including a clavobrachialis muscle not seen in other squirrels. Pygmy tree squirrels, which have evolved independently in three tribes, exhibit convergence of forelimb anatomy, including the loss or reduction of several muscles in the shoulder and forearm. The forelimb anatomy of flying squirrels is the most derived and differs from that of tree squirrels in details of shoulder, arm, and forearm musculature. Some of these muscular differences among squirrels have phylogenetic significance, being shared by closely related genera, but none has significance above the tribal level. Many of the differences suggest a variety of changes in function that are amenable to further study.