The attachments of the conus elasticus to the laryngeal skeleton: Physiologic and clinical implications

The attachments of the inferior and dorsal extensions of the lateral parts of the conus elasticus (CE) are not fully understood. A re-investigation was done in plastinated serial sections of 20 adult human larynges. The CE consists of a coherent sheet of connective tissue fibers dividing into two layers toward the inferior anchorage to the cricoid arch, and the posterior anchorage to the cricoid lamina. Caudally, the medial fiber layer is continuous with the submucous fibro-elastic membrane of the trachea and is not connected to the cricoid cartilage. The lateral caudal fiber layer is attached to the superior rim of the cricoid arch. Dorsally, both layers of the CE are fixed to the cricoid lamina, the lateral sheet to the lateral edge of the cartilage, the medial sheet to its anterior perichondrium near the midline. Towards the cricoarytenoid joint, the dorsal extension of the CE divides into a caudal and a cranial sheet including a fold of adipose tissue at the base of the arytenoid cartilage. The cranial layer extends towards the vocal process, the caudal layer radiates into the joint capsule and may therefore influence the complicated joint mechanics. The firm attachments of the CE to the cricoid cartilage probably counteract deformations of the CE during phonation. An insufficient fixation of the CE may contribute to an obstruction of the airways causing sleep apnea. © 1996 Wiley-Liss, Inc.     

杓状软骨的定位研究及其意义

目的为杓状软骨相关手术的术中定位提供解剖数据。方法观测30例60侧正常成人喉标本杓状软骨声带突和肌突形态及其与甲状软骨板的位置关系。结果 (1)测量了顶底间距等10项杓状软骨形态指标,除了甲杓肌附着深度外,其余指标具有性别差异(P0.05)(;2)肌突距甲状软骨下角下端距离:男(13.05±1.92)mm,女(11.76±1.79)mm;距甲状软骨板后缘间距:男(8.11±1.17)mm,女(6.95±1.26)mm;距甲状软骨板内膜间距:男(3.71±1.31)mm,女(3.65±1.23)mm。(3)杓状软骨肌突投影点位于甲状软骨板斜线后下区域,该投影点距甲状软骨下缘距离:男(7.12±1.43)mm,女(5.92±1.26)mm;距后缘距离:男(7.27±1.52)mm,女(5.81±1.47)mm。结论杓状软骨相关手术可根据甲状软骨后缘、下缘、环甲关节下缘来定位肌突。肌突距甲状软骨板内面最近,若从甲状软骨板斜线后区开窗寻找肌突可以缩短手术进路距离。     

Anatomical considerations on arytenoid cartilage dislocation

The cricoarytenoid joints of 12 human adult male and female larynges were studied with regard to the anatomical reasons for arytenoid cartilage dislocation. The specimens were impregnated with curable polymers as a whole and then cut into 600–800 μm sections along different planes. The articulating surface at the upper border of the cricoid lamina revealed a striking extension backward and occasionally even slightly distalward. This may allow the arytenoid cartilage to glide in a posterior direction until it partially looses its contact to the cricoid facet. In physiologic conditions, the arytenoid position is balanced along a sagittal plane between the posterior cricoarytenoid ligament dorsally and the thyroarytenoid muscle ventrally. If one of these structures is damaged, i.e., by medical disease or trauma, the arytenoid cartilage may be pushed easily in the opposite direction. Arytenoid dislocation mainly in a posterior direction is described in literature as a possible complication of endotracheal intubation. Preparatory pharmacological muscle relaxation leads to paralysis of the thyroarytenoid muscle and its ventrally directed traction on the arytenoid cartilage. As the shape of the articulating surfaces, especially the peculiarities of the cricoid facet, even facilitates a dorsally directed movement of the Arytenoid cartilage, it may be easily displaced in a posterior direction during the procedure of endotracheal intubation. © 1994 Wiley-Liss, Inc.     

Human patellar articular proportions: recent and Pleistocene patterns

The degrees of mediolateral asymmetry of the patellar articular facet, as well as the median and lateral articular angles of the facet, were compared across samples of recent humans and of Pleistocene archaic and modern fossil humans. All samples exhibit considerable variability in these patellar proportions. The articular angles are similar across the different samples, but there is a trend towards decreasing lateral angles with decreasing robusticity. The archaic humans exhibit significantly more symmetry of the medial and lateral facets than do any of the recent human samples. However, given the variability in medial versus lateral patellofemoral contact forces documented for extant humans and the roles of the distal oblique portions of vastus medialis and vastus lateralis in patellar stabilisation, it is unclear to what extent this variation in patellar articular proportions may affect knee kinesiology. The contrasts may be related to different levels of patellar stability and/or musculoskeletal hypertrophy, but they appear unlikely to have affected primary knee function.     

Calcaneal varus angle change in normal calcaneus: a three-dimensional finite element analysis

The objective of the study was to investigate the stress changes in the posterior articular surface of the calcaneus following alternation of the calcaneal varus angle in normal calcaneus and discuss the clinical significance of the calcaneal varus angle. Axial view radiographs of 165 volunteers were obtained to measure the calcaneal varus angle of normal calcaneus. A calcaneal model with different varus angle changes (including +2°, +4°, +6°, ?2°, ?4°, and ?6°) was established using Creo 2.0 software. Stress changes at different calcaneal varus angles in the posterior articular surface of the calcaneus under a load of 100 N were measured. Stressed areas in posterior articular facets were slightly fewer following +2°, +4°, and +6° changes in varus angle than in normal varus angles with stress concentering regions moving to the anteromedial aspect of the posterior calcaneal facet. However, stress concentering areas in posterior calcaneal facets following ?4° and ?6° changes in varus angle obviously moved to the anterior and posterior medial side of posterior calcaneal facets. Stress distribution in the posterior articular surface of the calcaneus varies with the calcaneal varus angle. The decrease in calcaneal varus angle following operative treatment of calcaneal fractures should be controlled within 2°.     

Three‐dimensional analysis of talar trochlea morphology: Implications for subject‐specific kinematics of the talocrural joint

Three‐dimensional (3D) behavior of the talocrural joint is primarily determined by the articular surface morphology of the talar trochlea and tibiofibular mortise. However, morphological features of the anterior and posterior regions of the talar trochlea remain unclear. The objectives of this study were to evaluate anterior and posterior radii of the medial and lateral talar trochlea and to estimate subject‐specific kinematics of the talocrural joint. Fifty dry tali were scanned using computed tomography to create 3D bone models. Radii of curvature of the anterior and posterior region at both the medial and lateral trochlea were calculated. Orientations of the dorsiflexion and plantarflexion axis passing through the centers of the circles fitted to the anterior region of the medial and lateral trochlea and through the centers of the circles fitted to the posterior region of the medial and lateral trochlea were evaluated, respectively. The anterior radius of the medial trochlea was significantly smaller than that of the lateral trochlea by a mean of 7.8 mm (P < 0.001). The posterior radius of the medial trochlea was larger than that of lateral trochlea in 30 samples (60%) and vice versa in 20 samples (40%). Unilateral asymmetric shape of anterior trochlea would induce external rotation of the talus during ankle dorsiflexion, whereas bilateral asymmetric shape of posterior trochlea would induce opposite axial rotations among subjects during ankle plantarflexion, which would help the physical therapists to restore talocrural joint motions to ideal state for patients with ankle injuries. Clin. Anat. 29:1066–1074, 2016. © 2016 Wiley Periodicals, Inc.     

Calcaneum talar facets,its diagnostic and clinical relevance to fracture

Introduction

Calcanei are classified into three to five patterns according to the number of superior articular facets present. As reported earlier the relative distribution of facets pattern varies with race and sex. Study of the calcaneal talar facets variation is important because it influence subtalar joint stability and knowledge of facets is essential while correcting foot deformities and for placing the screw in fracture fixation by orthopaedic surgeons.

The anatomy of the larynx of the bowhead whale,Balaena mysticetus,and its sound‐producing functions

This study describes the morphology of the laryngeal apparatus in bowhead whales (Balaena mysticetus) with respect to respiration, deglutition, and vocalization. We also examined the intrinsic cricoarytenothyroid muscle (Musculus (M.) diverticuli laryngei) which forms the laryngeal diverticulum, to ascertain its interactions with the laryngeal cartilages during respiration and sound production. Five fetal larynges and four from adult whales were studied using noninvasive imaging, as well as macroscopic and microscopic techniques. The larynx extends from the skull base into the thoracic inlet. The dorsally curved laryngeal stalk, supported by epiglottis and the corniculate processes of arytenoid cartilages, is situated within the nasopharynx. The epiglottic cartilage exhibits a prominent medial ridge. The arytenoid cartilages are rod‐shaped, and extend through the laryngeal cavity. The thyroid cartilage possesses a prominent caudal horn with a fibrous articulation to the ventrally incomplete cricoid cartilage. The M. thyroepiglotticus forms the connection between epiglottic and thyroid cartilages. The M. cricothyroideus lateralis connects the caudal horn of the thyroid cartilage with the cricoid cartilage and the M. cricothyroideus medialis connects the cricoid and thyroid cartilage. An extensive laryngeal diverticulum (Diverticulum laryngis), formed by the laryngeal mucosa and M. diverticuli laryngei, is positioned caudo‐ventral to the laryngeal vestibule. The mucosa thickens into a fold medial to the vocal processes of the arytenoid cartilages. Experiments with airflow combined with histological and anatomical evidence strongly suggest a sound producing function for these (vocal) folds. This analysis provides the first account of sound producing structures and function in bowhead whales. Anat Rec, 297:1316–1330, 2014. © 2014 Wiley Periodicals, Inc.     

Reinforcement of the larynx and trachea in echolocating and non-echolocating bats

The synchronization of flight mechanics with respiration and echolocation call emission by bats, while economizing these behaviors, presumably puts compressive loads on the cartilaginous rings that hold open the respiratory tract. Previous work has shown that during postnatal development of Artibeus jamaicensis (Phyllostomidae), the onset of adult echolocation call emission rate coincides with calcification of the larynx, and the development of flight coincides with tracheal ring calcification. In the present study, I assessed the level of reinforcement of the respiratory system in 13 bat species representing six families that use stereotypical modes of echolocation (i.e. duty cycle % and intensity). Using computed tomography, the degree of mineralization or ossification of the tracheal rings, cricoid, thyroid and arytenoid cartilages were determined for non-echolocators, tongue clicking, low-duty cycle low-intensity, low-duty cycle high-intensity, and high-duty cycle high-intensity echolocating bats. While all bats had evidence of cervical tracheal ring mineralization, about half the species had evidence of thoracic tracheal ring calcification. Larger bats (Phyllostomus hastatus and Pterpodidae sp.) exhibited more extensive tracheal ring mineralization, suggesting an underlying cause independent of laryngeal echolocation. Within most of the laryngeally echolocating species, the degree of mineralization or ossification of the larynx was dependent on the mode of echolocation system used. Low-duty cycle low-intensity bats had extensively mineralized cricoids, and zero to very minor mineralization of the thyroids and arytenoids. Low-duty cycle high-intensity bats had extensively mineralized cricoids, and patches of thyroid and arytenoid mineralization. The high-duty cycle high-intensity rhinolophids and hipposiderid had extensively ossified cricoids, large patches of ossification on the thyroids, and heavily ossified arytenoids. The high-duty cycle high-intensity echolocator, Pteronotus parnellii, had mineralization patterns and laryngeal morphology very similar to the other low-duty cycle high-intensity mormoopid species, perhaps suggesting relatively recent evolution of high-duty cycle echolocation in P. parnellii compared with the Old World high-duty cycle echolocators (Rhinolophidae and Hipposideridae). All laryngeal echolocators exhibited mineralized or ossified lateral expansions of the cricoid for articulation with the inferior horn of the thyroid, these were most prominent in the high-duty cycle high-intensity rhinolophids and hipposiderid, and least prominent in the low-duty cycle low-intensity echolocators. The non-laryngeal echolocators had extensively ossified cricoid and thyroid cartilages, and no evidence of mineralization/ossification of the arytenoids or lateral expansions of the cricoid. While the non-echolocators had extensive ossification of the larynx, it was inconsistent with that seen in the laryngeal echolocators.     

Variations in calcanean facets in Indian Tali

The various patterns in calcanean articular facets of 500 Indian tali have been observed and classified accordingly. Type I tali have one flat facet on plantar surface of its head (16%); Type II tali, the calcanean facet were divided into 2 parts by a indistinct or prominent ridge (78%); Type III tali, the calcanean articular facet was partly separated by nonarticular groove and partly by ridge (1%); Type IV tali have 2 articular facets on the plantar surface of head separated by nonarticular groove (3%); and Type V tali have a single facet on the plantar surface of head and this facet was continuous with the posterior calcanean facet (2%).     

Interspecific scaling patterns of talar articular surfaces within primates and their closest living relatives

The articular facets of interosseous joints must transmit forces while maintaining relatively low stresses. To prevent overloading, joints that transmit higher forces should therefore have larger facet areas. The relative contributions of body mass and muscle‐induced forces to joint stress are unclear, but generate opposing hypotheses. If mass‐induced forces dominate, facet area should scale with positive allometry to body mass. Alternatively, muscle‐induced forces should cause facets to scale isometrically with body mass. Within primates, both scaling patterns have been reported for articular surfaces of the femoral and humeral heads, but more distal elements are less well studied. Additionally, examination of complex articular surfaces has largely been limited to linear measurements, so that ‘true area’ remains poorly assessed. To re‐assess these scaling relationships, we examine the relationship between body size and articular surface areas of the talus. Area measurements were taken from microCT scan‐generated surfaces of all talar facets from a comprehensive sample of extant euarchontan taxa (primates, treeshrews, and colugos). Log‐transformed data were regressed on literature‐derived log‐body mass using reduced major axis and phylogenetic least squares regressions. We examine the scaling patterns of muscle mass and physiological cross‐sectional area (PCSA) to body mass, as these relationships may complicate each model. Finally, we examine the scaling pattern of hindlimb muscle PCSA to talar articular surface area, a direct test of the effect of mass‐induced forces on joint surfaces. Among most groups, there is an overall trend toward positive allometry for articular surfaces. The ectal (= posterior calcaneal) facet scales with positive allometry among all groups except ‘sundatherians’, strepsirrhines, galagids, and lorisids. The medial tibial facet scales isometrically among all groups except lemuroids. Scaling coefficients are not correlated with sample size, clade inclusivity or behavioral diversity of the sample. Muscle mass scales with slight positive allometry to body mass, and PCSA scales at isometry to body mass. PCSA generally scales with negative allometry to articular surface area, which indicates joint surfaces increase faster than muscles' ability to generate force. We suggest a synthetic model to explain the complex patterns observed for talar articular surface area scaling: whether ‘muscles or mass’ drive articular facet scaling is probably dependent on the body size range of the sample and the biological role of the facet. The relationship between ‘muscle vs. mass’ dominance is likely bone‐ and facet‐specific, meaning that some facets should respond primarily to stresses induced by larger body mass, whereas others primarily reflect muscle forces.     

Architecture of the lower end of the human tibia

The cancellous bone in the lower end of the human tibia is divisible into 3 broad categories, according to the density and disposition of its lamellae. Parallel fenestrated tubes of cancellous bone arise perpendicular to the inferior articular facet of the tibia and meet the shaft obliquely. They diverge from the neutral axis which inclines posterolaterally from the centre of the inferior articular facet. Horizontal lamellae course the medial malleolus, at right angle to its articular facet. The density of the cancellous bone decreases from the periphery to the neutral axis. Spicules of thin bone can be traced from the attachment of ligaments into cancellous bone lying perpendicular to the articular facets.     

枢椎各结构的解剖学部位研究

目的：明确枢椎各结构的解剖部位。方法：对57例干燥成人标本进行观察与测量，对8例新鲜枢椎标本进行CT薄层扫描，寻找残存的C1-2椎体间连接痕迹。以此为依据，明确枢椎各结构的具体部位。对20例志愿者的枢椎CT三维重建以及MRI图像进行分析，验证前述结论。结果：枢椎前结构的前下方为一三角形的突起部分，皮质较厚，同典型颈椎的椎体相似；两侧的三角形突起与上关节突之间为皮质凹陷区域；CT扫描见枢椎上终板残留位于三角形突起的上厅1．2～1．8mm处，呈圆饼形跨越约1．8～2．4mm同齿突的下终板残留结合在一起。位于椎弓侧方的上下关节突间部分以横突孔后结节为界可分为前后两部分，前者内倾角、上倾角大，后者小。前者外壁菲薄，多数有滋养血管孔存在，而后者内外侧皮质厚度较一致。结论：枢椎的椎体为位于前结构下方的三角形突起部分，椎弓根位于上关节突与椎体之间，椎弓侧方为上下关节突之间的连接部分，被横突孔后结节分为横突孔内界及峡部两个部分，后者为典型Hangman骨折的部位。     

South Indian calcaneal talar facet configurations and osteoarthritic changes

The purpose of this study was to determine the talar facet configuration of South Indian calcanei, measure the angle between the anterior and middle facet planes of these calcanei, and assess the relation between the above parameters and the degenerative changes in the subtalar joints. The angle between the anterior and middle talar facets was measured in 222 South Indian adult calcanei. The degree of sclerosis was measured on radiographs of the calcanei. Lipping and osteophytes around the joints were recorded by visual inspection. The facet patterns observed were fused anterior and middle facets (Type I), three separate facets (Type II), absence of the anterior facet (Type III), three merged facets (Type IV), and a new pattern of absent anterior and fused middle and posterior facets (Type V). An anterolateral impression was present in nine calcanei. Type I was the predominant pattern (72%). Type II configuration had the least mean angle (125 degrees) and had less number of calcanei with significant osteoarthritic changes. A wider angle was observed in Type I and Type III calcanei. Type IV and Type V were observed in only three and one calcanei, respectively. Lipping and osteophytes were observed in Type I to IV configurations. There was no correlation between the facet configuration and the radiological subchondral sclerosis in the posterior talar facet of the calcanei. This study reveals that the talar facet configuration of calcanei and the angle between the anterior and middle facets influence the stability of the subtalar joints and development of osteoarthritis.     

Do sagittal plane anatomical variations (angulation) of the cervical facets and C2 odontoid affect the geometrical configuration of the cervical lordosis?

Anthropometric and statistical evaluation of measurements from digitization of 252 lateral cervical radiographs were used to investigate any correlation between radiographic measurements of cervical lordosis with sagittal plane facet angulation, articular pillar height, and inclination of the C2 odontoid with respect to the body of C2. Some researchers have hypothesized that facet and odontoid architecture variations can cause a reduction in cervical lordosis. To evaluate this hypothesis, the posterior aspect of the C2 dens, vertebral body corners, and superior and inferior facet surfaces of C2-C7 were digitized on 252 lateral cervical X-rays to calculate global angle, segmental angles, dens angle, facet angles, and facet height. No correlation between facet angle, articular pillar height, and cervical curve was found. Similarly, no correlation between the sagittal angle of the dens and any angle of cervical curvature was identified. There was correlation between the global ARA C2-C7 angle and the Cobb angles at C1-C7 (r = 0.71) and C2-C7 (r = 0.82). There was correlation between the global inclination of the atlas vertebral angle (APL) and the Cobb angle at C1-C7 (r = 0.66), Cobb angle at C2-C7 (r = 0.39), ARA C2-C7 (r = 0.42), and anterior translation of C2 compared to C7 (r = -0.46). Because no correlation between cervical facet and odontoid architecture and any segmental or global angle of cervical lordosis was found, conservative and surgical rehabilitative techniques aimed at the reduction of sagittal cervical deformities do not need to account for a patient's architecture of the cervical facets nor odontoid.     

Comparison of medial and lateral posterior femoral condyle articular cartilage wear patterns

Background

While degenerative changes to the articular cartilage of the anterior and distal portions of the femoral condyles have been well studied in the literature, the changes that occur on the posterior femoral condyle are not as clear. The purpose of this study was to assess the difference in articular cartilage thickness between the medial and lateral posterior femoral condyles in knees undergoing unicompartmental knee arthroplasty.

Relative positions of the contacts on the cartilage surfaces of the knee joint

The goal of this project was to determine the centers of contacts (points of closest approach of the articular surfaces) for the tibio-femoral and patello-femoral joints throughout the flexion range, with a focus on high flexion where there is potential overlap between the contacts. The purpose was to determine the implications to the design of joint replacements and tissue engineered implants. Eight cadaveric knees were mounted in a rig with different loading combinations applied to the femur, including axial load, anterior/posterior shear, and internal/external torque. The range of flexion was 0 degrees to 155 degrees . Reference points on the bones measured during the experiments were used to later reconstruct an accurate 3D computer model of the multiple joint positions and determine the centers of contact between the opposing bearing surfaces. The tibio-femoral contact at 0 degrees flexion was displaced 5 mm anterior to the notch (the end point of the articular cartilage on the mid-line of the femoral sulcus) on the medial side, while remaining level with the notch on the lateral side. The patella contacts on the femur extended 15 mm posterior to the intercondylar notch with a centerline between the lateral and medial paths being several millimeters lateral to the center of the femur. The centers of the patella contacts were close to the inner margin of the medial condyle and did not directly overlap with the centers of the tibial contacts. On the lateral side the patella contacts ended where the tibial contacts began. For applications to medial unicondylar knee replacement design it was shown that patellar impingement on the anterior of the femoral component would occur at 110 degrees flexion. For TKR design, a continuous patella contact up to high flexion could be obtained by extending the trochlea 15 mm posterior to the intercondylar notch.     

膝关节半月板的三维断面解剖学研究

目的    观测膝关节半月板的断面形态特征和变化规律,为诊断膝部病变提供更为详尽的形态学资料。  方法    正常成人尸体膝关节片厚5 mm的连续断面标本27例,其中矢状断面标本9例,冠状断面标本12例,横断面标本6例。通过三维断面标本,观察膝关节半月板的断面形态特征。  结果    内侧半月板矢径（40.36±4.73）mm,横径（33.99±3.77）mm;外侧半月板矢径（34.51±2.18）mm,横径（34.51±　3.25）mm。内、外侧半月板前、后角厚度分别为（4.98±1.83）mm和（4.45±1.44）mm、（3.54±1.24）mm和（6.15±1.43）mm。半月板后角高度外侧大于内侧,外侧半月板后角高度大于前角。内侧半月板后角宽度大于前角。板股韧带出现率为75%。  结论    ①半月板前、后角部在矢状面上,体部在冠状面上显示最好,横断面可见半月板全貌。②由于内侧半月板与关节囊紧密相连,且后角宽度大于前角,致使其易受损伤。③外侧半月板后角高度大于内侧半月板后角及同侧前角,可能是导致外侧半月板后角较易受损的因素之一。