Recovery of electrical activity of anterior abdominal wall muscles after prolonged atrophy

It was shown that the functional state of the muscles of the anterior abdominal wall can be restored, as reflected in the parameters of their electrical activity, after prolonged atrophy due to a giant ventral hernia. A fuller recovery of the electromyographic indices is found if the anterior abdominal wall is reinforced with synthetic prosthetic material, for under these circumstances the muscle fibers are not caught up by the sutures and are in a functionally advantageous position.A. V. Vishnevskii Institute of Surgery, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR M. I. Kuzin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 4, pp. 302–304, April, 1979.     

The muscles of the abdominal wall: a new functional approach with anatomoclinical deductions

Summary the basic functional anatomy of muscle can be investigated by histochemical analysis of the muscle fibers and kinesiologic electromyography. The results of these techniques lead to anatomoclinical deductions based on the structure of muscle.Histochemical analysis of the striated fibers of a given muscle shows the existence of three functionally different populations of fibers. The relative abundance of each category of muscle fibers (expressed as a percentage) demonstrates the basic function of the muscle.The investigation of muscle function by kinesiologic electromyography shows that there are three categories of motor activity in the course of movement. These different types of motor activity are dependent upon the muscle fibers which display different physiological features, especially with respect to their contraction time.These two investigative techniques, the overall results of which are concordant, were applied to the study of the function of the muscles of the abdominal wall and led to the following anatomoclinical deduction: tonico-postural motor activity is predominant in the rectus abdominis and flat abdominal muscles. Kinesiologic electromyography also allowed to demonstrate the functional development of these muscles according to the age, sex, corpulence and physical activity of the subjects studied.

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Les muscles de la paroi de l'abdomen. Nouvelle approche fonctionelle et déductions anatomo-cliniques

Résumé L'anatomie fonctionnelle fondamentale des muscles peut être explorée par l'analyse histochimique des fibres musculaires et l'électromyographie cinésiologique, aboutissant à des déductions anatomo-cliniques basées sur la structure musculaire.L'analyse histochimique des fibres striées d'un muscle donné révèle qu'il contient trois populations de fibres fonctionnellement différentes. L'importance réciproque de chacune des catégories de fibres, exprimée en pourcentage met en évidence les fonctions fondamentales du muscle.L'exploration de la fonction des muscles par l'électromyographie cinésiologique montre qu'il existe au cours du mouvement, trois catégories d'activités motrices, soutenues par des fibres, dont les caractères physiologiques sont différents et spécialement leur temps de contraction.Les deux méthodes dont les résultats généraux sont concordants ont été appliquées à l'étude de la fonction des muscles de la paroi abdominale et ont permis les déductions anatomo-cliniques suivantes: l'activité motrice tonico-posturale est prédominante au niveau du muscle rectus abdominis et des muscles larges. L'électromyographie cinésiologique permet en outre de révéler l'évolution fonctionnelle de ces muscles on fonction de l'âge, du sexe, de la corpulence et de l'activité physique des sujets étudiés.

     

腹前外侧群肌的肌内神经分布模式

目的 揭示腹前外侧群肌的肌内神经分布模式,探讨其临床意义。 方法 取经甲醛固定的12具24侧中国成年尸体的腹前外侧群肌,行改良的Sihler染色。 结果 腹前外侧群肌的神经绝大多数源于节段性分布的胸神经。腹外斜肌各肌齿有独立的神经支配,在髂前上棘和髂结节之间的髂嵴上方有一纵向神经密集带。腹内斜肌腹股沟韧带中点上方有一纵向神经密集带,髂嵴上方有一横向神经密集带。腹横肌髂前上棘与第8、9肋软骨连结处之间有一弧形的神经密集带。腹直肌各肌腹中部有一横向神经密集带,上3个肌腹有独立神经支配。 结论 腹外斜肌和腹直肌可分出神经肌肉亚部;各肌内的神经密集带应被考虑为肉毒毒素A注射和局部麻醉的最佳靶点部位,不宜设为腹壁手术的切口部位。     

Inguinal canal development: The muscular wall and the role of the gubernaculum

The inguinal canal is an anatomically complex region. Although much has been written about the gubernaculum and the descent of the testis, little is known about the development of the abdominal wall itself. We dissected this inguinal canal in 75 fetuses between 10 and 25 weeks of gestation, 42 males and 33 females. We identified the anterior body‐wall muscular layers, located the gonads and uterus, and observed the formation of the scrotum. The gubernaculum was dissected, from the deep to the superficial ends and its distal attachments were determined. We proved that the muscular‐fibrous layers of the wall were well‐differentiated and observed how the inguinal canal enlarged with embryological development. In only one of the cases, an abnormal testis was found located in the scrotum. The upper end of the gubernaculum inserted into the inferior pole of the testis or the lateral angle of the uterus, according to gender. The lower end was attached by one or multiple tails, mainly on the pubic bone. This fact explained the clinical findings of ectopic testis. Observations of the abdominal wall and its relationship with the gubernaculum assisted us in explaining the development of the inguinal region, the formation of the inguinal canal, and the presence of the gubernaculum, in both genders. We intend to explain how the deep inguinal ring moves upwards, bringing the gubernaculum along with it, and thus determines the final form of the inguinal canal. Clin. Anat. 22:614–618, 2009. © 2009 Wiley‐Liss, Inc.     

Morphological changes in the anterior abdominal wall of rats with peritonitis and implanted synthetic film

Histological study and electron microscopy of the anterior abdominal wall and laparotomy wound closed using a polytetrafluoroethylene film was performed on rats with experimental peritonitis. We studied 4 types of polytetrafluoroethylene films differing in the size of micropores and technology of treatment. The tissue response differed after implantation of various films. A multilayer film with minimum size of pores was optimal to repair the laparotomy wound.Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 138, No. 12, pp. 698–701, December, 2004Municipal Hospital No.31This revised version was published online in April 2005 with a corrected cover date.     

The surface landmarks of the abdominal wall: a plea for standardization

Despite centuries of anatomical studies, controversies and contradictions still exist in the literature regarding the definition, anatomical terminology and the limits of the abdominal wall. We conducted a systematic research of books published from 1901 until December 2012 in Google Books. After the index screening, 16 remaining books were further assessed for eligibility. We decided to exclude journals. The aim of the study was to focus on surface landmarks and borders of the abdominal cavity. After this revision of the literature, we propose that the surface landmarks of the abdominal wall should be standardized.     

Architectural analysis and predicted functional capability of the human latissimus dorsi muscle

The latissimus dorsi is primarily considered a muscle with actions at the shoulder, despite its widespread attachments at the spine. There is some dispute regarding the potential contribution of this muscle to lumbar spine function. The architectural design of a muscle is one of the most accurate predictors of muscle function; however, detailed architectural data on the latissimus dorsi muscle are limited. Therefore, the aim of this study was to quantify the architectural properties of the latissimus dorsi muscle and model mechanical function in light of these new data. One latissimus dorsi muscle was removed from each of 12 human cadavers, separated into regions, and micro‐dissected for quantification of fascicle length, sarcomere length, and physiological cross‐sectional area. From these data, sarcomere length operating ranges were modelled to determine the force–length characteristics of latissimus dorsi across the spine and shoulder ranges of motion. The physiological cross‐sectional area of latissimus dorsi was 5.6 ± 0.5 cm² and normalized fascicle length was 26.4 ± 1.0 cm, indicating that this muscle is designed to produce a moderate amount of force over a large range of lengths. Measured sarcomere length in the post‐mortem neutral spine posture was nearly optimal at 2.69 ± 0.06 μm. Across spine range of motion, biomechanical modelling predicted latissimus dorsi acts across both the ascending and descending limbs of the force–length curve during lateral bend, and primarily at or near the plateau region (where maximum force generation is possible) during flexion/extension and axial twist. Across shoulder range of motion, latissimus dorsi acts primarily on the plateau region and descending limbs of the force length curve during both flexion/extension and abduction/adduction. These data provide novel insights into the ability of the latissimus dorsi muscle to generate force and change length throughout the spine and shoulder ranges of motion. In addition, these findings provide an improved understanding of the spine and shoulder positions at which the force‐generating capacity of this muscle can become jeopardized, and consequently how this may affect its spine‐stabilizing ability.     

Development of a pressure sensor system for unobtrusive monitoring of abdominal muscle activities

Surface electromyogram (sEMG) is often used by to objectively measure muscular activity during rehabilitation exercises. sEMG is accurate, but it is unsuitable for uses outside the clinic, and patients can benefit from an unobtrusive device which can be readily used to ubiquitously measure abdominal muscle activation. In this study, we present a pressure sensor system which can be latched onto a belt to measure abdominal muscle activation. sEMG and pressure sensor output were measured in 15 healthy young males during isometric trunk flexion exercise (public trials registration number, KCT0002351), and the results were highly correlated (median R?>?0.939). As initial contact force can change the pressure sensor sensitivity, the experiment was performed at two different levels of belt tightness, but the correlations did not significantly improve after tightening the belt, suggesting that the system can be used to ubiquitously and unobtrusively monitor abdominal muscle activity with minimal discomfort.     

Morphometry of the kangaroo spine and its comparison with human spinal data

The upright posture of the kangaroo suggests that the spine of the kangaroo could be a possible substitute model for biomechanical studies of the human spine. A prerequisite for this should be the agreement of anatomy in humans and kangaroos. The purpose of this study was to investigate the anatomical parameters of the kangaroo spine from C4 to S4 and compare them with existing anatomical data of the human spine. Eight complete spines of the red giant kangaroo were obtained and 21 anatomical parameters were measured from the vertebral bodies, spinal canal, endplate, pedicles, intervertebral discs, transverse, and spinous processes. Most similarities between kangaroo and human spines were found for the vertebral bodies in the cervical and the lumbar spine. The largest differences were evident for the spinous processes. Although both species are somehow upright, these differences may be explained by the way how they move. Jumping probably requires more muscle strength than walking on two legs.     

Evaluation of direct intramural injection to the bladder wall as a method for developing orthotopic tumor models

BackgroundBladder cancer poses a great burden on society and its high rate of recurrence and treatment failure necessitates use of appropriate animal models to study its pathogenesis and test novel treatments. Orthotopic models are superior to other types since they provide a normal microenvironment. Four methods are described for developing bladder cancer models inside the animal''s bladder. Direct intramural injection is one of these methods and is widely used. However, its efficacy in model development has not yet been studied. We aimed to evaluate the efficacy and success rate of the direct intramural injection method of developing an orthotopic model for the study of bladder cancer.MethodTumor cell lines were prepared in four microtubes. Aliquots of 200 × 10³ cells were injected through a 27 gauge needle into the ventral wall of the bladders of 4 male and 4 female BALB/c mice following a midline 1 cm laparotomy incision. In addition, 1 million cells from each microtube were injected into the flanks of control mice. To prevent infection and alleviate pain, 5 mg/kg enrofloxacin and 2.5 mg/kg flunixin meglumine, respectively, were injected subcutaneously.ResultsTumors formed in all mice, resulting in 100% take rate and zero post‐operation mortality. Surgery time was ≤15 min per mouse. In two mice, tumors were found in the peritoneal space as well.ConclusionDirect intramural injection is a rapid, reliable, and reproducible method for developing orthotopic models of bladder cancer. It can be done on both male and female mice and only requires readily available surgical tools. However, needle track can result in cell spillage and peritoneal tumors.     

Morphological study of two human facial muscles: Orbicularis oculi and corrugator supercilii

Human facial muscles are unique in that they do not cross joints and they function either to open and close the apertures of the face or to tug the skin into intricate movements producing facial expressions. Compared to other skeletal muscles of the body, little is known about the microscopic architecture and organization of facial muscles. It was hypothesized that facial muscles with different roles would possess differences in their cellular organization and morphology that would reflect their unique function. The palpebral orbicularis oculi (oo) and the corrugator supercilii (cs) were studied because they are in close topographical proximity to one another and share the same nerve supply and embryonic origin. This study compared the two muscles which were procured as biopsies from cosmetic surgery procedures. Architectural and morphological features were elucidated using a combination of conventional histological stains, immunocytochemistry and histochemistry. Quantitative measures of fiber sizes, shapes, and fiber‐type distributions were performed along with measures of capillary area per unit of contractile area (capillary index). Fiber‐type profiles and motor end‐plates were demonstrated by using antibodies to fast and slow myosins, as well as to neurofilament protein. The oo was shown to differ significantly from the cs on the basis of fiber shapes, sizes, and types. The oo muscle fibers were small, rounded, and 89% of them were of the fast‐twitch (Type II) variety. The muscle fibers in the cs were larger, polygonal, and only 49% of them were of the fast‐twitch variety. The capillary index of the cs was 2.4 times that of the oo. Clin. Anat. 12:1–11, 1999. © 1999 Wiley‐Liss, Inc.     

Functional and morphological evaluation of different polypropylene-mesh modifications for abdominal wall repair

Modern surgical hernia repair depends increasingly on synthetic meshes for the reconstruction of the abdominal wall. Despite the undisputed advantages of the polypropylene (PP) meshes currently available (Marlex^®, Prolene^®), reports of complications after implantation are increasing. Although, serious complications such as perforation and fistula formation are rare, minor and local complaints such as seromas, misfeelings and a decreased abdominal wall mobility are observed in about one-half of the patients. In regard to the exaggerated strength of the currently available mesh modifications a reduction of the material should improve the integration of the meshes into the artificial abdominal wall.

In the present study, the commercially available basic mesh Prolene^® has been compared to two newly constructed PP-mesh modifications with reduced amounts of PP. The modifications have gradually been adopted to the physiological requirements of abdominal wall stability and mobility by reducing the amount of PP to 64% (E-BLUE) and 24% (variant A) of the Prolene^® mesh (developed by ETHICON^®, Norderstedt, Germany).

All PP-mesh variants have been implanted in a rat model and studied by 3D-photogrammetry, tensiometry, light- and electron microscopy, as well as morphometry over implantation intervals of 3, 7, 14, 21 and 90 days.

The data show that current constructions of PP-meshes are oversized and definitely restrict abdominal wall mobility in the present model. Sufficient stability of the artificial abdominal wall is even guaranteed by PP-mesh modifications with a reduction of PP-quantity to about 25% of the Prolene^® mesh. The degree of fibrosis directly correlated with abdominal wall restriction, whereas the formation of connective tissue in the interface PP-fibre/host-issue depends on the amount and activity of the inflammatory reaction. The quantity and quality of inflammation, again, directly relies to the amount of PP and to the surface area in contact with the recipient tissues.

Altogether, the present study suggests that a modification of the PP-meshes could be helpful to prevent major and minor complications of surgical PP-meshes.     

Reviewing the vascular supply of the anterior abdominal wall: redefining anatomy for increasingly refined surgery

The abdominal wall integument is becoming the standard donor tissue for postmastectomy breast reconstruction, with its vascular supply of key importance to the reconstructive surgeon. Refinements in tissue transfer, from pedicled to free flaps and musculocutaneous to perforator flaps, have required increasing understanding of finer levels of this vascular anatomy. The widespread utilization of the deep inferior epigastric artery (DIEA) perforator flap, particularly for breast reconstruction, has rekindled clinical interest in further levels of anatomical detail, in particular the location and course of the musculocutaneous perforators of the DIEA. Advances in operative techniques, and anatomical and imaging technologies, have facilitated an increase in this understanding. The current review comprises an appraisal of both the anatomical and clinical literature, with a view to highlighting the key anatomical features of the abdominal wall vasculature as related to reconstructive flaps.     

Feasibility,accuracy and safety of a percutaneous fine‐needle biopsy technique to obtain qualitative muscle samples of the lumbar multifidus and erector spinae muscle in persons with low back pain

The lumbar muscular system, in particular the lumbar multifidus muscle (LM) and the erector spinae muscle (ES), plays an important role in stabilizing and mobilizing the lumbar spine. Based on the topography, the lumbar paraspinal muscles can be classified into local and global muscles. LM is part of the local system, whereas ES is part of the global system. Therefore, it is interesting to investigate the muscle fibre type composition in both muscles. There is accumulating evidence that nonspecific chronic low back pain is associated with lumbar muscle dysfunction. To further elucidate this lumbar paraspinal muscle dysfunction, it is important to understand the structural characteristics of individual muscle fibres of LM and ES. Muscle fibre type composition can be investigated in muscle tissue samples. So far, muscle samples are taken by using invasive procedures that are not well tolerated. The aim of this article was to evaluate the feasibility, accuracy and safety of a percutaneous fine‐needle biopsy technique to obtain muscle samples from LM and ES in persons with nonspecific chronic low back pain and to evaluate the feasibility of performing immunofluorescence analysis of myosin heavy chain isoform expression to investigate muscle fibre type composition. Preliminary investigations in cadavers were performed to determine the optimal vertebral level and puncture site to obtain muscle samples of LM and ES through a single skin puncture. In 15 persons with nonspecific chronic low back pain, muscle samples of LM and ES were taken under local anaesthesia with the percutaneous fine‐needle biopsy technique, preceded by determination of the puncture site with ultrasonography. Muscle fibre type composition was investigated using immunofluorescence analysis of myosin heavy chain expression. The subjects reported little or no pain and were willing to repeat the procedure. The obtained muscle tissue contained transverse‐sectioned muscle fibres in which muscle fibre contractile characteristics of the paraspinal muscles could be evaluated with immunofluorescence analysis of the myosin heavy chains. We can conclude that percutaneous microbiopsy appears to be feasible and accurate, and safe to use to obtain muscle tissue from the paraspinal muscles. The use of ultrasonography to determine the puncture site is necessary to ensure biopsy of the correct muscles and to ensure the safety of the procedure.     

MRI‐determined lumbar muscle morphometry in man and sheep: potential biomechanical implications for ovine model to human spine translation

The sheep is a commonly used animal model for human lumbar spine surgery, but only in vitro investigations comparing the human and ovine spine exist. Spinal musculature has previously not been compared between man and sheep. This additional knowledge could further indicate to what extent these species are biomechanically similar. Therefore, the purpose of the study was to investigate spinal muscle morphometric properties using magnetic resonance imaging (MRI) in different age groups of healthy human participants and sheep in vivo. Healthy human participants (n = 24) and sheep (n = 17) of different age groups underwent T1‐weighted MRI of the lumbar spine. Regions of interest of the muscles erector spinae (ES), multifidus (M) and psoas (PS) were identified. The ratio of flexor to extensor volume, ratio of M to ES volume, and muscle fat relative to an area of intermuscular fat were calculated. Sheep M to ES ratio was significantly smaller than in the human participants (sheep 0.16 ± 0.02; human 0.37 ± 0.05; P < 0.001), although flexor to extensor ratio was not significantly different between species (human 0.39 ± 0.08; sheep 0.43 ± 0.05; P = 0.06). Age did not influence any muscle ratio outcome. Sheep had significantly greater extensor muscle fat compared with the human participants (M left human 40.64%, sheep 53.81%; M right human 39.17%, sheep 51.33%; ES left human 40.86%, sheep 51.29%; ES right human 35.93%, sheep 44.38%; all median values; all P < 0.001), although PS did not show any significant between‐species differences (PS left human 36.89%, sheep 33.67%; PS right human 32.78%, sheep 30.09%; P < 0.05). The apparent differences in the size and shape of sheep and human lumbar spine muscles may indicate dissimilar biomechanical and functional demands, which is an important consideration when translating to human surgical models.     

成人下腹壁厚度测量及其对根据指南针原理设计的排尿报警装置的意义

目的　了解正常成人下腹壁厚度,并探讨其相关因素及其对根据指南针原理设计的排尿报警装置的意义。 方法　应用B超连续测量l00例成人的下腹壁及其浅层和深层的厚度,膀胱的前后径、上下径及左右径,并测量身高、体质量、测量点到脐部的距离,计算体质量指数（BMI）和膀胱容量,分析影响下腹壁厚度的相关因素。 结果　本组成人的下腹壁厚度(23.4±6.6)mm,95%可信区间为22.1～24.7　mm,与下腹壁深层厚度、浅层厚度和BMI、体质量、测量点到脐部的距离呈正相关(P<0.05),与膀胱容量、膀胱的上下径和左右径呈负相关(P<0.05),而与性别、身高、年龄、膀胱的前后径无相关性(P>0.05)。 结论　应用超声测量的成人下腹壁厚度为(23.4±6.6)mm,营养状态是最重要的影响因素,这为根据指南针原理设计的排尿报警装置的可行性提供了新的证据,对该装置的进一步研究具有重要的参考意义。     

Hepatopulmonary syndrome: the role of intra-abdominal hypertension and a novel mouse model

Objective: Hepatopulmonary syndrome (HPS) is considered as a triad of chronic liver disease, pulmonary vascular ectasia and severe hypoxemia. The study aims to investigate the pathological mechanism of intra-abdominal pressure (IAP) in HPS and establish a novel mouse model. Methods: Fifty male ICR mice were randomly divided into experimental and control group, receiving subcutaneous injection of carbon tetrachloride and water, respectively. Mice in experimental group were then divided into 4 sub-groups with the intraperitoneal injection of different volume of albumin to form different IAP (0, 5, 10 and 20 cmH₂O). All the mice were then sacrificed 24 hours later and blood gas analysis was conducted. In addition, liver and lung histopathology was also examined. Results: Blood gas analysis in different IAP suggested the respiratory alkalosis. Arterial partial pressure of oxygen significantly decreased in the IAP=10 cmH₂O (68.13 ± 3.56, P<0.01) and 20 cmH₂O (66.00 ± 3.78, P<0.01). Alveolar-arterial oxygen pressure difference increased markedly in the IAP=10 cmH₂O (54.60 ± 6.80, P<0.001) and 20 cmH₂O (57.04 ± 5.60, P<0.001). According to lung histopathology, macrophages were found to accumulate in the alveolar spaces and the widened alveolar walls were detected. In addition, there was visible blood stasis in the alveolar walls and numerous red blood cells extravasated into air space in the IAP=10 and 20 cmH₂O. Conclusions: Our study suggested that intra-abdominal hypertension was a significant pathological mechanism of HPS. Meanwhile, we have established a novel mouse model that will now be optimized with further investigation of the mechanism and therapeutic targets of HPS.     

Fetal development of deep back muscles in the human thoracic region with a focus on transversospinalis muscles and the medial branch of the spinal nerve posterior ramus

Fetal development of human deep back muscles has not yet been fully described, possibly because of the difficulty in identifying muscle bundle directions in horizontal sections. Here, we prepared near-frontal sections along the thoracic back skin (eight fetuses) as well as horizontal sections (six fetuses) from 14 mid-term fetuses at 9-15 weeks of gestation. In the deep side of the trapezius and rhomboideus muscles, the CD34-positive thoracolumbar fascia was evident even at 9 weeks. Desmin-reactivity was strong and homogeneous in the superficial muscle fibers in contrast to the spotty expression in the deep fibers. Thus, in back muscles, formation of the myotendinous junction may start from the superficial muscles and advance to the deep muscles. The fact that developing intramuscular tendons were desmin-negative suggested little possibility of a secondary change from the muscle fibers to tendons. We found no prospective spinalis muscle or its tendinous connections with other muscles. Instead, abundant CD68-positive macrophages along the spinous process at 15 weeks suggested a change in muscle attachment, an event that may result in a later formation of the spinalis muscle. S100-positive intramuscular nerves exhibited downward courses from the multifidus longus muscle in the original segment to the rotatores brevis muscles in the inferiorly adjacent level. The medial cutaneous nerve had already reached the thoracolumbar fascia at 9 weeks, but by 15 weeks the nerve could not penetrate the trapezius muscle. Finally, we propose a folded myotomal model of the primitive transversospinalis muscle that seems to explain a fact that the roofing tile-like configuration of nerve twigs in the semispinalis muscle is reversed in the multifidus and rotatores muscles.     

The ovariectomized sheep as a model for human bone loss

The aim of this study was to determine the effects of ovariectomy on the trabeculae of ovine iliac bone, with a view to the further development of a model for human osteoporosis. Seven ovariectomized (OVX) and five control Dorset ewes were observed for one year. Iliac crest bone samples were obtained at the time of ovariectomy ("time 0") and again when the animals were killed 12 months later. At "time 0" and at 3-month intervals thereafter samples of blood and urine were collected for the assay of serum 17beta-oestradiol and osteocalcin (OC) and urinary deoxypyridinium (D-PYR). One year after ovariectomy, trabecular bone volume and thickness were reduced (P<0.05) and trabecular separation was increased (P<0.05) as compared with the controls. In OVX sheep, serum 17beta-oestradiol concentrations were significantly lower at the end of the experiment than at "time 0", while serum OC and urinary D-PYR concentrations were significantly higher (P<0.001). The results suggest that the OVX sheep is a valid model for changes in trabecular bone architecture associated with oestrogen deficiency, especially in women experiencing early menopause.