Association between the developing sphenoid and adult morphology: A study using sagittal sections of the skull base from human embryos and fetuses

The developing sphenoid is regarded as a median cartilage mass (basisphenoid [BS]) with three cartilaginous processes (orbitosphenoid [OS], ala temporalis [AT], and alar process [AP]). The relationships of this initial configuration with the adult morphology are difficult to determine because of extensive membranous ossification along the cartilaginous elements. The purpose of this study was therefore to evaluate the anatomical connections between each element of the fetal sphenoid and adult morphology. Sagittal sections from 25 embryos and fetuses of gestational age 6–34 weeks and crown-rump length 12–295 mm were therefore examined and compared with horizontal and frontal sections from the other 25 late-term fetuses (217–340 mm). The OS was identified as a set of three mutually attached cartilage bars in early fetuses. At all stages, the OS-post was continuous with the anterolateral part of the BS. The BS included the notochord and Rathke's pouch remnant in embryos and early fetuses. The dorsum sellae was absent from embryos, but it protruded from the BS in early fetuses before a fossa for the hypophysis became evident. Although not higher than the hypophysis at midterm, the dorsum sellae elongated superiorly after gestational age 25 weeks. In early fetuses, the AP was located on the side immediately anterior to the otic capsule. The AT developed on the side immediately posterior to the extraocular rectus muscles. At late term, the greater wing was formed by membranous bones from the AT and AP. The AT and AP formed a complex bridge between the BS and the greater wing. A small cartilage, future medial pterygoid process (PTmed) was located inferior to the AT in early fetuses. At midterm, one endochondral bone and multiple membranous bones formed the PTmed. The lateral pterygoid process (PTlat) was formed by a single membranous bone plate. Therefore, we connected fetal elements and the adult morphology as follows. (1) Derivative of the OS makes not only the lesser wing but also the anterior margin of the body of the sphenoid. (2) Derivatives of the BS are the body of the sphenoid including the sella turcica and the dorsum sellae. (3) Most of the greater wing including the foramen rotundum and the foramen oval originate from the AT and AP and multiple membranous bones. (4) The PTmed originate from endochondral bones and multiple membranous bones, while the PTlat derive from a single membranous bone.     

The prenatal development of the human humerus

Forty pairs of humeri, from a series of embryos and fetuses ranging from 26 to 342 mm in crown-rump length, were measured, radiographed, and sectioned for microscopic study. A primary bony collar was present before the end of the embryonic period, and in a 27 mm embryo it extended for nearly one-third of the length of the humerus. Erosion of the collar occurred at the end of the embryonic period. By about 37 mm, endochondral ossification began, and cartilage canals were invading the proximal epiphysis. As endochondral ossification proceeded proximally and distally and growth zones became established, periosteal bone formation also proceeded longitudinally and, until about 18 weeks, extended about one millimeter beyond the zone of cartilage destruction in the growth zones. Subsequently the extents of periosteal and endochondral ossification were the same and at term occupied 79% of the length of the humerus. Trabeculation of the bony collar began in the embryonic period. Fusion of endochondral trabeculae with the inner aspect of the periosteal shell began by 61 mm. A central marrow cavity free of trabeculae was consistently present after 86 mm. Evidence of reconstruction appeared in the proximal end by 73 mm and in the distal end by 113 mm, and was always present after 97 and 125 mm respectively.     

The third vascular route of the inner ear or the canal of Cotugno: Its topographical anatomy,fetal development,and contribution to ossification of the otic capsule cartilage

Three vascular routes to the inner ear are known: (a) through the internal acoustic meatus with the vestibulocochlear nerve; (b) from the endolymphatic duct aperture; and (c) along the canal of Cotugno (CC) inserted into the vestibular part of the ear from the superior or brain side. The third is believed to contain only veins. Examinations of 33 human embryos and fetuses at 6–40 weeks demonstrated that (a) the CC appeared as a recess of epidural mesenchymal tissues at the superior aspect of the otic capsule cartilage in embryos and it was inserted deeply to issue multiple peripheral divisions inferolaterally and posteriorly at midterm; (b) the CC consistently passed through a ring of the superior or anterior semicircular canal and contained both, the arteries from the vestibulocochlear nerve origin at the midbrain and the vein draining into the sigmoid sinus or petrosal sinuses; and (c) the CC appeared not to contribute to ossification of the otic capsule cartilage but, after endochondral ossification of the internal ear, woven bone development occurred along a smooth interface of the CC with the ossified ear. In contrast, another interface between the developing bone and the residual cartilage of the otic capsule was rough and wavy with many short bony columns, called osseous globules. In addition, the endolymphatic duct accompanied veins but no arteries. Our results show that the CC is a major vascular route to the vestibular part of the otic capsule cartilage, but its role appears to be limited after ossification.     

A morphometric analysis of craniofacial growth and changes in spatial relations during secondary palatal development in human embryos and fetuses

Staged human embryos and fetuses in the Carnegie Embryological Collection were morphometrically analyzed to show craniofacial dimensions and changes in spatial relations, and to identify patterns that would reflect normal developmental events during palatal formation. Normal embryos aged 7–8 weeks postconception (Streeter-O'Rahilly stages 19–23) and fetuses aged 9–10 weeks postconception, in eight groups with mean crownrump (CR) lengths of 18–49 mm, were studied with cephalometric methods developed for histologic sections. In the 4-week period studied, facial dimensions increased predominantly in the sagittal plane with extensive changes in length (depth) and height, but limited changes in width. Growth of the mandible was more rapid than the nasomaxillary complex, and the length of Meckel's cartilage exceeded the length of the oronasal cavity at the time of horizontal movement of the shelves during stage 23. Simultaneously with shelf elevation, the upper craniofacial complex lifted, and the tongue and Meckel's cartilage extended forward beneath the primary palate. Analysis of spatial relations in the oronasal cavity showed that the palatomaxillary processes became separated from the tongue-mandibular complex as the head extended, and the tongue became positioned forward with growth of Meckel's cartilage. As the head position extended by 35°, the cranial base angulation was unchanged and the primary palate maintained a 90° position to the posterior cranial base. However, the sagittal position of the maxilla relative to the anterior cranial base increased by 20° between stages 19 and 23. In the late embryonic and early fetal periods, the mean cranial 128° and the mean maxillary position angulation of approximately 34° were similar to the angulations previously shown to be present later prenatally and postnatally. The results suggest that human patterns of cranial base angulation and maxillary position to the cranial base develop during the late embryonic period when the chondrocranium and Meckel's cartilage form the primary skeleton.     

基于3.0 T MRI的二维定量指标在胎儿肱骨发育评估中的应用价值

目的 探讨基于3.0 T MRI的二维定量指标在胎儿肱骨发育评估中的应用价值。方法 回顾性研究。纳入2018年1月—2021年10月泰安市中心医院74例非生长发育受限胎儿的MRI资料。受检孕妇年龄20~46（30.8±5.9）岁,孕周26~37（32.7±3.4）周。采集真实稳态进动快速成像（TrueFISP）序列MRI,测量胎儿肱骨的二维定量指标（肱骨干长度,肱骨近侧和远侧软骨骨骺横径、前后径、高径,以及肱骨总长度）。应用Pearson相关分析二维定量指标与孕龄的相关性;观察肱骨近侧和远侧次级骨化中心的出现时间。结果 胎儿肱骨干长度、肱骨总长度和肱骨近侧软骨骨骺前后径均与孕龄呈高度正相关（r=0.83、0.84、0.72,P值均<0.001）;胎儿肱骨近侧软骨骨骺横径和肱骨远侧软骨骨骺横径、前后径、高径均与孕龄呈中度正相关（r=0.64、0.56、0.53、0.53,P值均<0.001）;胎儿肱骨近侧软骨骨骺高径与孕龄呈低度正相关（r=0.38,P=0.001）。肱骨远侧次级骨化中心最早出现时间在36~37⁺⁶周,26~35⁺⁶周均未见;26~37⁺⁶周胎儿肱骨近侧均未出现次级骨化中心。结论 基于3.0 T MRI的二维定量指标可较好评估孕龄26~37⁺⁶周胎儿肱骨生长发育,可为产前诊断胎儿肱骨疾病提供参考依据。     

Duodenal window revisited: A histological study using human fetuses

To assess the development of the duodenal window in fetuses, we examined semiserial histological sections of 59 human fetuses with a crown‐rump length of 27–156 mm (～4–18 weeks of gestation). In 44 of the 54 fetuses with horizontal sections, the duodenal window was formed by interdigitation of the anterior and posterior muscle slips from the proper duodenal circular muscle coat. The anterior slips approached the common bile duct from the anterior side and wound around the bile duct from the right aspect, whereas the posterior slips approached the main pancreatic duct from the posterior side, reaching the left or outer aspect of the duct without winding. These slips may become longitudinal muscles in the ampulla after birth. Six specimens showed variations in this typical pattern, in that the posterior muscle slips as well as the duodenal longitudinal muscle coat wound around the bile duct. In the remaining four specimens, we observed an abnormal union of the bile and pancreatic ducts, with the duodenal circular muscles suddenly ending along the window or slightly inserted into the right side of the common duct after joining. In all later‐stage fetuses, the common sphincter surrounded both the bile and pancreatic ducts in the ampulla. Consequently, at and along the duodenal window, the proper duodenal circular muscle seemed to contribute to fetal sphincter formation. The window was not a simple hiatus but a functional interface between the sphincter and the duodenal wall. Clin. Anat. 26:598–609, 2013. © 2012 Wiley Periodicals, Inc.     

The prenatal development of the human femur

The study reported here is the result of a detailed investigation of the changes in shape of the femur with growth and torsion, the type, rate and character of ossification, and the onset, subsequent course, and general features of remodeling. Forty pairs of femurs, from a series of embryos and fetuses ranging from 26 to 342 mm in crown-rump length, were measured, radiographed, and sectioned for microscopic study. A primary bony collar was present before the end of the embryonic period, and in a 27 mm embryo it extended for about one-fifth of the length of the femur. Erosion of the collar was evident at 34 mm. and invasion and destruction of calcified cartilage were occurring by 37 mm. Cartilage canals first appeared in the proximal epiphysis at 57 mm and in the distal epiphysis at 61 mm. Along with the progression of endochondral ossification proximally and distally and the establishment of growth zones, periosteal bone formation also proceeded in both directions, and, until 275 mm, extended about 1 mm beyond the zones of cartilage destruction. After 275 mm, the extents of periosteal and endochondral ossification were the same and at term occupied almost four-fifths of the length of the femur. Trabeculation of the bony collar was first noted at 37 mm. Fusion of endochondral trabeculae with the inner aspect of the periosteal shell began by 61 mm. A central marrow cavity free of trabeculae was present at 86 mm and thereafter. Evidence of reconstruction appeared in both proximal and distal ends by 92 mm, and was consistently present in both ends in all specimens of 111 mm and larger.     

Distribution of Matrix Proteins in Perichondrium and Periosteum During the Incorporation of Meckel's Cartilage into Ossifying Mandible in Midterm Human Fetuses: An Immunohistochemical Study

Immunohistochemical localization of versican and tenascin‐C were performed; the periosteum of ossifying mandible and the perichondrium of Meckel's cartilage, of vertebral cartilage, and of mandibular condylar cartilage were examined in midterm human fetuses. Versican immunoreactivity was restricted and evident only in perichondrium of Meckel's cartilage and vertebral cartilage; conversely, tenascin‐C immunoreactivity was only evident in periosteum. Therefore, versican and tenascin‐C can be used as molecular markers for human fetal perichondrium and fetal periosteum, respectively. Meckel's cartilage underwent endochondral ossification when it was incorporated into the ossifying mandible at the deciduous lateral incisor region. Versican immunoreactivity in the perichondrium gradually became weak toward the anterior primary bone marrow. Tenascin‐C immunoreactivity in the primary bone marrow was also weak, but tenascin‐C positive areas did not overlap with versican‐positive areas; therefore, degradation of the perichondrium probably progressed slowly. Meanwhile, versican‐positive perichondrium and tenascin‐C‐positive periosteum around the bone collar in vertebral cartilage were clearly discriminated. Therefore, the degradation of Meckel's cartilage perichondrium during endochondral ossification occurred at a different rate than did degradation of vertebral cartilage perichondrium. Additionally, the perichondrium of mandibular condylar cartilage showed tenascin‐C immunoreactivity, but not versican immunoreactivity. That perichondrium of mandibular condylar cartilage has immunoreactivity characteristic of other periosteum tissues may indicate that this cartilage is actually distinct from primary cartilage and representative of secondary cartilage. Anat Rec, 297:1208–1217, 2014. © 2014 Wiley Periodicals, Inc.     

Anatomical evaluation and clinical importance of the tibiofibular syndesmosis ligaments

The aim of this study was to describe the detailed anatomical arrangement of ligaments of the tibiofibular syndesmosis and to highlight the clinical aspects of fracture dislocations. This study was performed on 42 legs of adult human embalmed cadavers. Tibiofibular syndesmosis ligaments attachments and their mutual relationships were described and their dimensions were measured. The anterior tibiofibular ligament is usually composed of three parts. This ligament runs obliquely at laterodistaly direction making 35° angle with horizontal plane and posteriorly 65° angle with sagittal plane. The posterior tibiofibular ligament runs almost horizontally 20° angle with horizontal plane. The mean thicknesses of tibial and fibular attachments are 6.38±1.91 mm and 9.67±1.74 mm, respectively. The inferior transverse ligament originates from just below the posterior tibiofibular ligament, which has variations on the shape and dimensions due to its attachment points. The average length is 36.60±9.51 mm. The network between the fibular notch and the distal fibula has been filled with the interosseous tibiofibular ligament whose fibers follow the laterodistal and anterior direction from the tibia to the fibula. It lies proximally 30–40 mm from the mortise. At the inferior view of the tibiofibular syndesmosis a pyramidal shaped cartilaginous facet was observed which was attached to the fibula. The length of this cartilage was variable. Some of synovial plicas from the ankle joints synovial membrane were observed at this view. We conclude that the results of this study may be useful to both orthopedic surgeons and radiologists for anatomic evaluation of the tibiofibular syndesmosis area.     

Fetal Development of the Incisive Canal,Especially of the Delayed Closure Due to the Nasopalatine Duct: A Study Using Serial Sections of Human Fetuses

The incisive canal of the incisive bone or premaxilla is a narrow bony canal through which pass the nasopalatine nerve and its concomitant vessels. However, its fetal development remains obscure. To assess its development, serial frontal sections of the heads of 26 human fetuses, of gestational age 9–20 weeks (crown‐rump length, 46–183 mm), were examined. The nerve initially passed through a wide loose tissue space, but after ossification of the upper part of the incisive bone at 12–15 weeks, the canal became narrow and filled with tight fibrous tissue. Canals in seven fetuses were dilated and open unilaterally or bilaterally. In two of these seven fetuses, a nasopalatine duct passed through the canal and connected the nasal cavity to a central lumen of the paramedian epithelial pearl in the incisive fossa (not to an oral cavity). Even if the canal was closed, the duct was likely to remain above and below the closed part. Paramedian pearls were present in all specimens larger than 110 mm (15 weeks), with or without association of midline pearls. These paramedian pearls usually protruded toward and/or extended into the dilated or open canal, suggesting that these pearls, not any primitive oronasal communication pathway, contributed to keeping the canal open. The dilated canal, located on the superomedial side of the second and third teeth buds, seemed to be usually closed by further ossification. Even in fetuses, the nasopalatine duct seemed to be a variant or unusual phase of development temporally occurring after normal palate fusion. Anat Rec, 300:1093–1103, 2017. © 2016 Wiley Periodicals, Inc.     

Early Fetal Development of the Human Cochlea

The cochlear scalas are differentiated from a single tube with a lining by the tall epithelium, that is, the cochlear duct. However, we have no information about the mechanism involved in the formation of the scalas. We evaluated histological sections taken from 20 fetuses: eight each at 8–9 weeks [early stage; 28–45 mm crown–rump length (CRL)] and 11–12 weeks (middle stage; 52–74 mm CRL), and four at 14–15 weeks (late stage; 90–110 mm CRL) of gestation. In four of eight early‐stage and in all eight middle‐stage specimens, we observed irregular perilymphatic spaces and their fusion; these spaces tended to be larger in the future scala tympani than in the future scala vestibuli. The cochlear duct epithelium was positive for cytokeratin 19 in contrast to the other parts of the cochlea. The tectorial membrane appeared in two of eight middle‐stage and all four late‐stage specimens. After 16 weeks, mesothelial lining of the scala may follow the development of aquaporin‐positive thin blood vessels along the scala wall. Notably, gap formation of the cochlear duct epithelium at a site facing the scala tympani consistently occurred before the development of S100 protein‐negative organ of Corti. This gap is likely to correspond to a site occupied finally by Hensen's cells. All these steps likely started in the basal coil and extended to the apical side of the cochlea. These findings suggest that leakage through the epithelial gap of endolymph, with a high concentration of potassium ions, causes mesenchymal cell death, leading to the coalescence of vacuoles containing low potassium perilymph. Anat Rec, , 2011. © 2011 Wiley‐Liss, Inc.     

新鲜标本的下胫腓联合韧带解剖特点及临床意义

目的： 研究新鲜标本下胫腓联合韧带的解剖学特点,为下胫腓联合韧带相关损伤及韧带重建提供解剖学依 据。方法： 选取新鲜胫腓下联合标本,剥离新鲜标本的下胫腓联合的肌、血管及筋膜组织,对下胫腓联合前、后、 横韧带进行解剖学测量,包括胫腓下联合前、后、横韧带的近端长度、远端长度、平均宽度、与水平面的夹角、 冠状面的夹角等相关解剖学数据。结果： 下胫腓联合前韧带近、远端平均长度为（8.51±0.70）mm、（19.03±1.35） mm,平均宽度（15.98±1.17） mm,与水平面、冠状面夹角分别为（42.27±3.43）°、（20.50±4.69）° ;下胫腓联 合后韧带近、远端平均长度为（9.32±0.62）mm、（16.92±1.76）mm,平均宽度（14.36±0.88）mm,与水平 面、冠状面夹角分别为（40.96±3.16）°、（13.10±1.99）°;下胫腓联合横韧带近、远端平均长度为（18.46±2.48） mm、（21.87±2.52）mm,平均宽度（4.56±0.17）mm,与水平面、冠状面夹角分别为（30.60±3.65）°、（13.48±1.60）°。 对左右、男女的下胫腓联合前、后、横韧带的解剖学数据进行对比,差异均无统计学意义。结论： 了解下胫腓联 合韧带各解剖结构及其特点,有助于指导下胫腓联合韧带损伤的修复和重建,帮助外科医生制定手术方案,改善 预后。     

下胫腓联合解剖参数的多层螺旋CT测量

目的 利用MSCT扫描图像观察正常下胫腓联合的形态以及测量相关解剖学参数,为临床精确诊断下胫腓联合分离提供解剖学依据及有效的诊断方法。方法 回顾性分析2013年6月—2016年2月,大连大学附属中山医院45例行双踝CT检查的单侧踝关节外伤患者的健侧踝关节影像资料。取距离胫距关节面9~11 mm的水平位CT扫描图像分析下胫腓联合形态,并测量胫腓骨中心距离、胫腓骨间隙宽度及胫腓骨前缘距离,分析各组参数的统计学差异。结果 45例下胫腓联合CT影像显示其形态有3种,其中为半圆形14例(31.11%),新月形15例(33.33%),矩形16例(65.56%)。半圆形下胫腓联合的胫腓骨中心距离、胫腓骨间隙宽度和胫腓骨前缘距离分别为(2.69±0.19)cm、(2.45±0.46)mm和(8.48±2.30)mm,新月形的分别为(2.82±0.17)cm、(2.74±0.90)mm和(6.80±1.62)mm,矩形的分别为(2.89±0.25)cm、(3.15±0.8)mm和(6.86±1.89)mm。其中,半圆形下胫腓联合的胫腓中心距离和胫腓骨间隙宽度均较矩形的小,差异均有统计学意义(q=3.722、3.602,P值均<0.05);而半圆形胫腓骨前缘距离较矩形的大,差异有统计学意义(q=3.217,P<0.05);但是,新月形的相关参数分别与半圆形和矩形的比较,差异均无统计学意义(P值均>0.05)。结论 国人的下胫腓联合在CT影像上可分为半圆形、新月形和矩形三种形态。以下胫腓联合前后缘的切线作为测量基线,可提高各参数测量的可重复性,为进一步研究国人下胫腓联合提供了有效的方法。     

Development and surgical anatomy of the round window niche

The round window niche is a bony pouch of the tympanic cavity and clinically frequently explored, therefore its topography has fundamental impact on microsurgery. A total of 783 macerated and formalin-fixed temporal bones were used to study the normal anatomy of the round window and its development. The ossification of the niche starts in the 16th fetal week and is complete at birth. A process of the otic capsule, called the cartilage bar, forms the inferior wall of the round window niche. The anterior and superior walls of the niche form by intramembranous ossification, whereas the posterior and inferior walls predominantly form by enchondral ossification. The uneven growth of different walls of the round window niche can alter the shape of the entrance, which results in eight different types of niches: extremely narrow, descending tegmen, anterior septum, bony membrane, open fundus, exostosis, jugular dome and trabeculae.     

Fetal development of the transverse atlantis and alar ligaments at the craniovertebral junction

Although the fetal development of the craniovertebral junction has long been of major interest to embryologists from the viewpoint of segmentation, development of the associated ligaments has received scant attention. Using semiserial horizontal sections from 18 embryos and fetuses (six embryos with a crown-rump length (CRL) of 20-26 mm or ~6-7 weeks of gestation; five fetuses with a CRL of 32-58 mm or 8-9 weeks; seven fetuses with a CRL of 90-115 mm or 14-15 weeks) without any abnormalities of cartilage configuration such as atlas assimilation, we studied the ligamentous structures along and around the odontoid process of the axis. The transverse atlantis and alar ligaments originated from a common mesenchymal condensation possibly corresponding to the proatlas segment: the former started to develop slightly earlier than the latter, and the morphologies of both were established at 7 weeks of gestation. Development of the joint cavitation around the odontoid process began in the mid-anterior area at 6 weeks, but was not fully completed even at 15 weeks (115 mm CRL). The presumptive joint cavity expressed vimentin and CD34 and contained abundant CD68-positive macrophages. We always found a mid-anterior joint cavitation facing the basi-occipital, but the embryological meaning remained unclear. The apical ligament appeared most likely to originate from the notochord sheath. The notochord was exposed from the tip of the odontoid process toward the loose epidural tissue and entered the occipital bone, but was difficult to trace to the anterior surface of the basi-occipital.     

Vermiform Appendix During the Repackaging Process from Umbilical Herniation to Fixation onto the Right Posterior Abdomen

The anatomical position of the vermiform appendix varies among adults, and these variations are responsible for differences in the symptoms of appendicitis. However, to date no study has examined how and when these variations occur during fetal development. The present study examined horizontal sections of 27 midterm fetuses (crown rump length [CRL] 38–97 mm, gestational age approximately 8–15 weeks). There were 10 fetuses (CRL 56 mm or more) in which the cecum and appendix were in a posterosuperior site near the right kidney (postmigration phase), and 12 fetuses (CRL 39–72 mm) in which the ileocecal junction and appendix remained on the visceral surface of the liver in the anterior or anterolateral abdominal cavity (migration phase, after physiological umbilical herniation). Analysis of the 12 fetuses in the migration phase indicated that the appendix extended inferiorly in eight fetuses and superiorly in four fetuses. Likewise, a “preileal” appendix (a morphology in which the distal part of the appendix was in front of the terminal ileum) was present in eight of these fetuses. Extension of the appendix superiorly or inferiorly during the migration phase seems unrelated to the topographical relationship of the appendix with the terminal ileum at the postmigration phase in fetuses and in adults. Conversely, it seems likely that a retroileal appendix leads to a coiled appendix behind the ileocecal junction. “Guidance” by the liver surface seemed to be important for posterior migration, which ended with the ascent of the liver. Clin. Anat., 33:667–677, 2020. © 2019 Wiley Periodicals, Inc.     

Aspects of skeletal development in fragile X syndrome fetuses

The purpose of the present investigation was to describe the skeletal development in prenatal fragile X syndrome. We studied fetuses (4 males, 2 females), with gestational ages (GA) 12-14 weeks, from 5 unrelated, different, known carrier mothers. Because of trauma to the fetus during abortion, different parts of the 6 fetuses were available for investigation. The vertebral column and the facial skeleton of all the fetuses were examined, the feet and hands of 5 fetuses, and the cranial base of 3 fetuses. The tissue remnants were examined radiographically and histochemically, and the results compared with previously published normal findings. Radiographic findings included normal ossification sequence, except for 1 fetus where there was an abnormal sequence in the first finger; normal morphology of ossification centres; and nasal bones were absent in the 5 fetuses and present in 1 (14 weeks of gestation). The histological study suggests presence of an acid mucopolysaccharide malfunction in the supporting tissue, because the normal cartilage resorption and orthochromatic cartilage reactions do not appear during the initial enchondral ossification. In addition, the apoptosis of ectodermally derived cells (notochord and palatal epithelial layers) appears delayed or abnormal. The sella turcica was malformed in the 2 fetuses investigated for sella turcica morphology.     

基于防腐标本的胫腓连结解剖特点及临床意义

目的 基于防腐标本胫腓连结的解剖特点，探讨胫腓连结的临床意义。方法 选取西南医科大学的51份胫腓连结防腐标本，通过对标本进行解剖，观察其结构解剖特点，并测量胫腓连结相关几何数据。结果 分别测量胫腓前、后、下横韧带的几何数据，用均值±标准差描述，包括：胫腓前韧带近端长度、远端长度、宽度分别为（8.53±0.69、19.06±1.34、15.99±1.44）mm；胫腓后韧带近端长度、远端长度、宽度分别为（9.34±0.63、16.92±1.76、14.36±0.89）mm；胫腓横韧带近端长度、远端长度、宽度分别为（18.42±2.48、21.93±2.59、4.56±0.17）mm；胫腓前韧带与冠状面夹角、与水平面夹角分别为（20.49±4.86、42.20±3.42）°；胫腓后韧带与冠状面夹角、与水平面夹角分别为（13.2±2.06、40.92±3.13）°；胫腓横韧带与冠状面夹角、与水平面夹角分别为（13.45±1.57、32.73±3.70）°；数据分析显示，胫腓前、后、横韧带在男女之间差异存在统计学意义，而在左右足之间差异无统计学意义。结论 胫腓连结对踝关节的稳定性具有重要意义，其解剖结构对临床治疗有重要指导意义。     

The onset of ossification in the human calcaneus

Summary A (silver) radiographic and microscopic study of the onset of ossification in the calcaneus of 177 human fetuses between 49 and 150 mm C.-R. length has revealed the presence of two independent and developmentally different ossific sites. A lateral locus, intramembranous (parachondral) in origin and precocious in appearance, was observed in slightly over 16% of the fetuses examined between 93 mm (the first appearance of this bone) and 150 mm C.-R. It occupied the vascular connective tissue within the anterior portion of a distinct groove on the inferolateral wall of the cartilaginous calcaneus between the retrotrochlear eminence anterosuperiorly, and the lateral process of the tuber posteroinferiorly. A centrally situated, primary ossific centre, endochondral in origin, was detected in only 11% of the fetuses between 118 mm (the initial appearance of this centre) and 150 mm C.-R. It was situated in the centre of the anterior third of the cartilaginous calcaneus in relatin to the sustentaculum tali medially and to a distinct cartilaginous prominence on its lateral surface. Only four fetuses possessed both ossific sites (lateral and central): at 122, 143, 145, and 150 mm C.-R., and in only one of these was continuity established between them. One fetus (122 mm) possessed two independent endochondral centres (superior and inferior).Supported in part by research programme project grant No. HD-08658, Institute of Child Health and Human Development, National Institutes of Health, U.S.A.     

Contribution of the anterior longitudinal ligament to ossification and growth of the vertebral body: an immunohistochemical study using the human fetal lumbar vertebrae

Using 15 mid-term human fetuses, we examined the role of the spine anterior and posterior longitudinal ligaments (ALL, PLL) in ossification of the lumbar vertebral body. By 18 weeks, a pair of calcified tissue or cortical walls had developed on the anterior and posterior sides of the ossification center. These calcified cortical walls were more highly eosinophilic than trabecular or woven bone in the ossification center. Vimentin-positive osteoblasts were arranged in line along the outer surface of the walls. However, few CD68-positive osteoclasts were evident around the walls, suggesting that the calcification in the walls was similar to periosteal ossification. The anterior cortical wall was connected tightly with the ALL by fiber bundles, but the posterior wall was separated from the PLL by the basivertebral (central) vein and loose tissues. Notably, by 30 weeks, the anterior cortical wall had become attached to and incorporated into the ALL. Thus, the ALL seemed to act as an active periosteum for ossification. Although our materials were limited in number and stage, we hypothesized that, in contrast to the PLL, the mature anterior cortical wall corresponds to a calcified fibrocartilage adjacent to the ALL and forms a bone–ligament interface maintaining an ossification potential.