The functional anatomy of the iliotibial band during flexion and extension of the knee: implications for understanding iliotibial band syndrome

Iliotibial band (ITB) syndrome is a common overuse injury in runners and cyclists. It is regarded as a friction syndrome where the ITB rubs against (and 'rolls over') the lateral femoral epicondyle. Here, we re-evaluate the clinical anatomy of the region to challenge the view that the ITB moves antero-posteriorly over the epicondyle. Gross anatomical and microscopical studies were conducted on the distal portion of the ITB in 15 cadavers. This was complemented by magnetic resonance (MR) imaging of six asymptomatic volunteers and studies of two athletes with acute ITB syndrome. In all cadavers, the ITB was anchored to the distal femur by fibrous strands, associated with a layer of richly innervated and vascularized fat. In no cadaver, volunteer or patient was a bursa seen. The MR scans showed that the ITB was compressed against the epicondyle at 30 degrees of knee flexion as a consequence of tibial internal rotation, but moved laterally in extension. MR signal changes in the patients with ITB syndrome were present in the region occupied by fat, deep to the ITB. The ITB is prevented from rolling over the epicondyle by its femoral anchorage and because it is a part of the fascia lata. We suggest that it creates the illusion of movement, because of changing tension in its anterior and posterior fibres during knee flexion. Thus, on anatomical grounds, ITB overuse injuries may be more likely to be associated with fat compression beneath the tract, rather than with repetitive friction as the knee flexes and extends.     

The functional anatomy of the human anterior talofibular ligament in relation to ankle sprains

The anterior talofibular ligament is the most commonly injured ligament in the ankle. Despite considerable interest in the clinical outcome of treatment protocols, we do not know whether the distinctive pattern of localization of the injuries relates to regional differences in the structure and molecular composition of the ligament. To address this issue, ligaments were examined by histology and immunohistochemistry. Differences in the structure of its two attachments (i.e. entheses) were evaluated with quantitative, morphometric techniques, and regional differences in the distribution of collagens, glycosaminoglycans and proteoglycans were determined qualitatively by immunolabelling. Morphometric analyses showed that bone density was less at the fibular attachment, but that enthesis fibrocartilage was more prominent. Immunohistochemistry revealed the presence of a fibrocartilage (containing type II collagen and aggrecan) at the site where the ligament wraps around the lateral talar articular cartilage in a plantarflexed and inverted foot: the fibrocartilage is regarded as an adaptation to resisting compression. We propose that avulsion fractures are less common at the talar end of the ligament because (1) bone density is greater here than at the fibular enthesis, and (2) stress is dissipated away from the talar enthesis by the 'wrap-around' fibrocartilaginous character of the ligament near the talar articular facet.     

The arterial anatomy of the Achilles tendon: Anatomical study and clinical implications

The Achilles tendon is the most frequently ruptured tendon in the lower limb and accounts for almost 20% of all large tendon injuries. Despite numerous published studies describing its blood supply, there has been no uniformity in describing its topography. The current study comprises a detailed anatomical study of both the intrinsic and extrinsic arterial supply of the Achilles tendon, providing the detail sought from studies calling for improved planning of surgical procedures where damage to the vascularity of the Achilles tendon is likely. A dissection, microdissection, histological, and angiographic study was undertaken on 20 cadaveric lower limbs from 16 fresh and four embalmed cadavers. The Achilles tendon is supplied by two arteries, the posterior tibial and peroneal arteries. Three vascular territories were identified, with the midsection supplied by the peroneal artery, and the proximal and distal sections supplied by the posterior tibial artery. The midsection of the Achilles tendon was markedly more hypovascular that the rest of the tendon. The Achilles tendon is at highest risk of rupture and surgical complications at its midsection. Individuals with particularly poor supply of the midsection may be at increased risk of tendon rupture, and approaches to the tendon operatively should consider the route of supply by the peroneal artery to this susceptible part of the tendon. Clin. Anat. 22:377–385, 2009. © 2009 Wiley‐Liss, Inc.     

Tendon matrix composition and turnover in relation to functional requirements

Tendons are dense regular connective tissue structures that are defined based on their anatomical position of connecting muscle to bone. Despite these obvious commons features tendons from different locations within the body show remarkable variation in terms of their morphological, molecular and mechanical properties which relates to their specialized function. An appreciation of these differences is necessary to understand all aspects of tendon biology in health and disease. In our work, we have used a combination of mechanical assessment, histological measurements and molecular analysis of matrix in functionally distinct tendons to determine relationships between function and structure. We have found significant differences in material and molecular properties between spring-like tendons that are subjected to high strains during locomotion and positional tendons which are subjected to much lower strains. Furthermore, we have data to suggest that not only is the matrix composition different but also the ability of cells to synthesize and degrade the matrix (matrix turnover) varies between tendon types. We propose that these differences relate to the magnitude of strain that the tendon experiences during normal activities in life. Tendon cells may be preprogrammed during embryological development for the strain they will encounter in life or may simply respond to the particular strain environment they are subjected to. The elucidation of controlling mechanisms resulting in tendon cell specialization will have important consequences for cell based therapies and engineering strategies to repair damaged tendons.     

The distribution of body fat in relation to habitual activity

42 young female subjects aged 19–24 years were selected to form 3 groups based on the estimated hours of physical activity taken each week. They represented 1. very active, 2. active, and 3. sedentary people. Their body fat and fat-free mass (FFM) were estimated from densitometry (corrected for the lung residual volume present during total immersion) and the distribution of subcutaneous fat mass (SFM) was examined by measuring skinfold thickness at 11 sites. The regression of body density on log σ4 skinfolds was significantly different between the 3 groups for a given skinfold value of up to 40 mm, which corresponded to a higher density value for the very active subjects. The possibility that this observation might be explained by differences in the distribution of fat between subcutaneous and internal fat stores was examined, using empirical calculations of SFM. The proportion of fat situated subcutaneously was higher than previously reported (0·65), with a range of individual values (0·41–0·87), but no significant differences in fat distribution between the 3 groups. Group differences in the relationship between body density and log σ4 skinfolds might be explained by variation in the composition of the FFM which may result from differing levels of habitual physical activity. The implication of this possibility in estimating total body fat from density measurements are discussed.     

The clinical surface anatomy anomalies of the palmaris longus muscle in the Black African population of Zimbabwe and a proposed new testing technique

The presence of the palmaris longus muscle (PLM) is highly variable. Rates of absence vary from 0.6% in the Korean population to as high as 63.9% in the Turkish population. The tendon of PLM may be absent on one or both forearms, may have duplicated tendons on one forearm or may be laterally shifted to the extent that the tendon of the PLM lies superficial to that of flexor carpi radialis muscle. Among Black American populations, in which there is usually mixed ancestry, rates of absence are 3.5%. Only two studies have been performed on Black African populations: in Republic of Congo and Uganda, and each showed widely differing rates of absence of 3.0% and 14.6%, respectively. In this study, a total of 890 Black Zimbabwean subjects in Harare aged between 8 and 13 years, were examined for clinical surface anatomy anomalies of the tendon of PLM. The results showed that the tendon of the PLM was absent unilaterally in 0.9% of the population, and bilaterally absent in 0.6% with an overall rate of absence of 1.5%. Other variations noted were a laterally shifted PLM in 1.1% of subjects and duplicated tendons on one forearm, which was the least prevalent anomaly, in 0.2% of subjects. The author proposes a new technique to test the tendon of PLM, which combines resisted thumb abduction and resisted wrist flexion. The proposed technique capitalizes on the role of the PLM as an important abductor of the thumb. Clin. Anat. 22:230–235, 2009. © 2009 Wiley‐Liss, Inc.     

颈部血管和神经与颈椎的关系及应用解剖

目的观测颈部血管、神经与颈椎的关系,为颈椎手术提供帮助。方法在40侧成人标本上,观测颈部血管、神经的长度及起止点与相邻颈椎间的距离。结果面动脉与舌神经伴行,起点距相邻C3椎体为(18.5±7.2)mm。舌动脉与舌下神经伴行,起点距相邻C2～3椎体为(19.7±8.4)mm。甲状腺上动脉与喉上神经外支伴行,起点距相邻C3椎体为(17.0±5.7)mm,止点距相邻C5椎体为(18.2±2.5)mm。喉上动脉与喉上神经内支伴行,起点距相邻C3椎体为(15.7±6.7)mm,止点距相邻C3椎体为(19.7±5.8)mm。甲状腺下动脉起点距相邻C7椎体为(17.3±5.5)mm,止点距相邻C7椎体为(11.3±3.4)mm。结论颈上部有数支动脉起至C2～3高度,此处显露喉上神经尤为重要。颈中部尽量减少对颈内脏鞘和颈动脉鞘的牵拉。颈下部则熟悉喉返神经与甲状腺下动脉的关系。手术途径选右侧为宜,以避免胸导管的损伤。     

Gross anatomy examination performances in relation to medical students' knowledge of classical latin and greek

The ability of medical students to acquire anatomical and medical terminologies could be influenced by their knowledge of classical Greek and Latin. In a previous study (Stephens and Moxham 2016 , Clin. Anat. 29:696at. ), it was reported that, while newly recruited medical students have a very favorable attitude toward the need to understand these classical languages, final year students see no benefit. In this study, we tested the hypothesis that, regardless of attitude, students in the initial stages of their medical education perform better at both summative and formative anatomy examinations if they have prior knowledge of Greek and Latin. First year medical students at Cardiff University who had been involved in the previous study concerning attitudes toward the relevance of the classical languages to medical education were evaluated in terms of their examination results in anatomy. Two hundred and twenty‐seven students responded to a questionnaire (83% of the class) that categorized students into their linguistic knowledge and skills and their performances in formative and summative examinations were analyzed. For medical students with prior knowledge of classical Greek and Latin performed better in both summative and formative anatomy examinations. The results are therefore consistent with our hypothesis. Clin. Anat. 31:501–506, 2018. © 2018 Wiley Periodicals, Inc.     

The use of functional neuroimaging to evaluate psychological and other non-pharmacological treatments for clinical pain

A large number of studies have provided evidence for the efficacy of psychological and other non-pharmacological interventions in the treatment of chronic pain. While these methods are increasingly used to treat pain, remarkably few studies focused on the exploration of their neural correlates. The aim of this article was to review the findings from neuroimaging studies that evaluated the neural response to distraction-based techniques, cognitive behavioral therapy (CBT), clinical hypnosis, mental imagery, physical therapy/exercise, biofeedback, and mirror therapy. To date, the results from studies that used neuroimaging to evaluate these methods have not been conclusive and the experimental methods have been suboptimal for assessing clinical pain. Still, several different psychological and non-pharmacological treatment modalities were associated with increased pain-related activations of executive cognitive brain regions, such as the ventral- and dorsolateral prefrontal cortex. There was also evidence for decreased pain-related activations in afferent pain regions and limbic structures. If future studies will address the technical and methodological challenges of today's experiments, neuroimaging might have the potential of segregating the neural mechanisms of different treatment interventions and elucidate predictive and mediating factors for successful treatment outcomes. Evaluations of treatment-related brain changes (functional and structural) might also allow for sub-grouping of patients and help to develop individualized treatments.     

Compositional and functional properties of high-density lipoproteins in relation to coronary in-stent restenosis

IntroductionIn-stent restenosis (ISR) is an unfavorable outcome that occurs in patients after coronary stenting. Use of drugs such as statins as well as drug-eluting stents has only been partially effective in reducing the rate of ISR. Since low high-density lipoprotein cholesterol (HDL-C) concentration is a pivotal cardiovascular disease risk factor, this study aimed to evaluate the compositional and functional alterations of HDL in individuals with ISR.Material and methodsThis case-control study included 21 ISR, 26 non-ISR (NISR), 16 angiography-negative, and 18 healthy subjects. Serum HDL2 (d: 1.063–1.125 g/ml) and HDL3 (d: 1.125–1.210 g/ml) subfractions were extracted from each subject using sequential ultracentrifugation. The capacity of HDL to efflux cellular cholesterol from lipid-loaded macrophages as well as to take up free cholesterol (FC) from triglyceride-rich lipoproteins (TGRLs) during lipolysis was assessed.ResultsNo difference was found in the HDL2 and HDL3 content of free cholesterol and total protein among the groups. The NISR group showed lower triglyceride content in HDL2 and higher phospholipid content in HDL3 relative to healthy subjects. Strong positive correlations were found between the cholesterol efflux capacity (CEC) of HDL2 and its phospholipid content in the healthy (r = 0.50), angiography-negative (r = 0.55) and ISR (r = 0.52) groups. The capacity of apolipoprotein B (apoB)-depleted serum to take up free cholesterol was not different among the groups.ConclusionsDespite some compositional alterations, the capacity of HDL to efflux cholesterol from lipid-loaded macrophages as well as to take up free cholesterol from TGRLs during lipolysis was not associated with ISR in this study.     

The significance of respiration for thoracic duct flow in relation to other driving forces of lymph flow

Experiments were performed to study the effect of respiratory intrathoracic pressure changes upon thoracic duct lymph propulsion as compared to other forces driving lymph flow in anaesthetized and artificially ventilated dogs. The effect of an open bilateral pneumothorax upon thoracic duct flow and protein composition was determined at rest, with passive limb movement and during saline infusion. The effect of hyperventilation was also tested.Thoracic duct flow was 30 l/min/kg, 45 l/min/kg and 60 l/min/kg at rest, with passive limb movement and saline infusion, respectively. These flows were decreased by opening the pneumothorax by 11 l/min/kg, 12 l/min/kg and 8 l/min/kg, respectively, and returned to the control level after the thorax was closed. The lymph protein concentration and lymph albumin to globulin ratio were not changed significantly. During hyperventilation, lymph flow was increased and showed a retarded decrease after hyperventilation had ceased. Lymph protein composition was not changed significantly by hyperventilation.The data confirm that lymph is propelled in anaesthetized dogs by respiratory intrathoracic pressure changes. The significance of this respiratory pump decreases, when lymph flow is increased by activation of the tissue pump or vis a tergo. Consequently, the respiratory pump may be assumed to play a secondary role in lymph propulsion in the conscious state when the other forces driving lymph flow are more predominant.Presented in part at the 48th meeting of the Deutsche Physiologische Gesellschaft [18]Supported by the Deutsche Forschungsgemeinschaft     

The response of bone, articular cartilage and tendon to exercise in the horse

Horses can gallop within hours of birth, and may begin training for athletic competition while still growing. This review cites studies on the effects of exercise on bone, tendon and articular cartilage, as detected by clinical and research imaging techniques, tissue biochemical analysis and microscopy of various kinds. For bone, alterations in bone mineral content, mineral density and the morphology of the mineralized tissue are the most common end-points. Apparent bone density increases slightly after athletic training in the cortex, but substantially in the major load paths of the epiphyses and cuboidal bones, despite the lower material density of the new bone, which is deposited subperiosteally and on internal surfaces without prior osteoclastic resorption. With training of greater intensity, adaptive change is supervened by patho-anatomical change in the form of microdamage and frank lesions. In tendon, collagen fibril diameter distribution changes significantly during growth, but not after early training. The exact amount and type of protracted training that does cause reduction in mass average diameter (an early sign of progressive microdamage) have not been defined. Training is associated with an increase in the cross-sectional area of some tendons, possibly owing to slightly greater water content of non-collagenous or newly synthesized matrix. Early training may be associated with greater thickness of hyaline but not calcified articular cartilage, at least in some sites. The age at which adaptation of cartilage to biomechanical influences can occur may thus extend beyond very early life. However, cartilage appears to be the most susceptible of the three tissues to pathological alteration. The effect of training exercise on the anatomical or patho-anatomical features of connective tissue structures is affected by the timing, type and amount of natural or imposed exercise during growth and development which precedes the training.     

Functional variation of neck muscles and their relation to feeding style in Tyrannosauridae and other large theropod dinosaurs

Reconstructed neck muscles of large theropod dinosaurs suggest influences on feeding style that paralleled variation in skull mechanics. In all examined theropods, the head dorsiflexor m. transversospinalis capitis probably filled in the posterior dorsal concavity of the neck, for a more crocodilian‐ than avian‐like profile in this region. The tyrannosaurine tyrannosaurids Daspletosaurus and Tyrannosaurus had relatively larger moment arms for lateroflexion by m. longissimus capitis superficialis and m. complexus than albertosaurine tyrannosaurids, and longer dorsiflexive moment arms for m. complexus. Areas of dorsiflexor origination are significantly larger relative to neck length in adult Tyrannosaurus rex than in other tyrannosaurids, suggesting relatively large muscle cross‐sections and forces. Tyrannosaurids were not particularly specialized for neck ventroflexion. In contrast, the hypothesis that Allosaurus co‐opted m. longissimus capitis superficialis for ventroflexion is strongly corroborated. Ceratosaurus had robust insertions for the ventroflexors m. longissimus capitis profundus and m. rectus capitis ventralis. Neck muscle morphology is consistent with puncture‐and‐pull and powerful shake feeding in tyrannosaurids, relatively rapid strikes in Allosaurus and Ceratosaurus, and ventroflexive augmentation of weaker jaw muscle forces in the nontyrannosaurids. Anat Rec, 290:934–957, 2007. © 2007 Wiley‐Liss, Inc.     

Evidence for functional interactions of morphine in substantia nigra and striatum in relation to muscular rigidity in rats

Systemic administration of morphine (15 mg/kg i.p.) induced muscular rigidity in rats, which was recorded from the gastrocnemius-soleus muscle as tonic activity in the electromyogram. Administration of morphine (5 or 10 μg) into the pars compacta of the substantia nigra antagonized the rigidity in a dose-dependent manner, whereas administration of morphine at a dose of 5 μg into the pars reticulata of the substantia nigra enhanced the tonic EMG activity. When morphine and naloxone were co-administered intranigrally, the tonic EMG activity was not affected.     

Expression and functional characterization of missense mutations in ATP8A2 linked to severe neurological disorders

ATP8A2 is a P4‐ATPase (adenosine triphosphate) that actively flips phosphatidylserine and phosphatidylethanolamine from the exoplasmic to the cytoplasmic leaflet of cell membranes to generate and maintain phospholipid asymmetry. Mutations in the ATP8A2 gene have been reported to cause severe autosomal recessive neurological diseases in humans characterized by intellectual disability, hypotonia, chorea, and hyperkinetic movement disorders with or without optic and cerebellar atrophy. To determine the effect of disease‐associated missense mutations on ATP8A2, we expressed six variants with the accessory subunit CDC50A in HEK293T cells. The level of expression, cellular localization, and functional activity were analyzed by western blot analysis, immunofluorescence microscopy, and ATPase activity assays. Two variants (p.Ile376Met and p.Lys429Met) expressed at normal ATP8A2 levels and preferentially localized to the Golgi‐recycling endosomes, but were devoid of ATPase activity. Four variants (p.Lys429Asn, pAla544Pro, p.Arg625Trp, and p.Trp702Arg) expressed poorly, localized to the endoplasmic reticulum, and lacked ATPase activity. The expression of these variants was increased twofold by the addition of the proteasome inhibitor MG132. We conclude that the p.Ile376Met and p.Lys429Met variants fold in a native‐like conformation, but lack key amino acid residues required for ATP‐dependent lipid transport. In contrast, the p.Lys429Asn, pAla544Pro, p.Arg625Trp, and p.Trp702Arg variants are highly misfolded and undergo rapid proteosomal degradation.     

The relation between common sleep problems and emotional and behavioral problems among 2- and 3-year-olds in the context of known risk factors for psychopathology

The contribution of sleep problems to emotional and behavioral problems among young children within the context of known risk factors for psychopathology was examined. Data on 2- and 3-year-olds, representative of Canadian children without a chronic illness, from three cross-sectional cohorts of the Canadian National Longitudinal Study of Child and Youth were analysed ( n  = 2996, 2822, and 3050). The person most knowledgeable (PMK), usually the mother, provided information about her child, herself, and her family. Predictors included: child health status and temperament; parenting and PMK depressive symptomatology; family demographics (e.g., marital status, income) and functioning. Child sleep problems included night waking and bedtime resistance. Both internalizing/emotional (i.e., anxiety) and externalizing/behavioral problems (i.e., hyperactivity, aggression) were examined. Adjusting for other known risk factors, child sleep problems accounted for a small, but significant, independent proportion of the variance in internalizing and externalizing problems. Structural equation models examining the pathways linking risk factors to sleep problems and emotional and behavioral problems were a good fit of the data. Results were replicated on two additional cross-sectional samples. The relation between sleep problems and emotional and behavioral problems is independent of other commonly identified risk factors. Among young children, sleep problems are as strong a correlate of child emotional and behavioral problems as PMK depressive symptomatology, a well-established risk factor for child psychopathology. Adverse parenting and PMK symptomatology, along with difficult temperament all contribute to both sleep problems and emotional and behavioral problems. Children's sleep problems appear to exacerbate emotional and behavioral problems.