Growth and shaping of metacarpal and carpal cartilage anlagen: application of morphometry to the development of short and long bone. A study of human hand anlagen in the fetal period.

A histological and morphometric analysis of human metacarpal and carpal anlagen between the 16th and 22nd embryonic weeks was carried out with the aim of studying the establishment of the respective anlage architecture. No differences in the pattern of growth were documented between the peripheral and central zones of the metacarpal epiphyses and those of the carpals. The regulation of longitudinal growth in long bone anlagen occurred in the transition zone between the epiphysis and the diaphysis (homologous to the metaphyseal growth plate cartilage in more advanced developmental stage of the bone). Comparative zonal analysis was conducted to assess the chondrocyte density, the mean chondrocyte lacunar area, the paired chondrocyte polarity in the orthogonal longitudinal and transverse planes, and the lacunar shape transformation in the metacarpal. In transition from epiphysis to diaphysis chondrocyte density decreased and mean lacunar area increased. No significant differences in the chondrocyte maturation cycle were observed between proximal/distal metacarpal epiphyses and the carpal anlagen. The number of paired chondrocyte oriented along the growth vector was significantly higher in both proximal/distal transition zones between epiphysis and diaphysis. Human metacarpals shared with experimental models (like mice and nonmammal tetrapods) an early common chondrocyte maturation cycle but with a different timing due to the slower embryonic and fetal developmental rate of human anlagen.

Carpal Coalitions and Metacarpal Synostoses: A Review.

Background: Carpal coalition and metacarpal synostosis are uncommon congenital anomalies of the carpus and hand. Methods: A comprehensive review of the literature was performed to help guide surgical and non-surgical treatment of carpal coalition and metacarpal synostosis. Results: The embryology, epidemiology, medical and surgical management, and associated outcomes are detailed. Conclusions: Most patients with these disorders will likely benefit from conservative measures. Surgery should be considered in patients with pain and limitations in wrist and hand function.

Functional analysis of limb transcriptional enhancers in the mouse.

Transcriptional enhancers are genomic sequences bound by transcription factors that act together with basal transcriptional machinery to regulate gene transcription. Several high-throughput methods have generated large datasets of tissue-specific enhancer sequences with putative roles in developmental processes. However, few enhancers have been deleted from the genome to determine their roles in development. To understand the roles of two enhancers active in the mouse embryonic limb bud we deleted them from the genome. Although the genes regulated by these enhancers are unknown, they were selected because they were identified in a screen for putative limb bud-specific enhancers associated with p300, an acetyltransferase that participates in protein complexes that promote active transcription, and because the orthologous human enhancers (H1442 and H280) drive distinct lacZ expression patterns in limb buds of embryonic day (E) 11.5 transgenic mice. We show that the orthologous mouse sequences, M1442 and M280, regulate dynamic expression in the developing limb. Although significant transcriptional differences in enhancer-proximal genes in embryonic limb buds accompany the deletion of M1442 and M280 no gross limb malformations during embryonic development were observed, demonstrating that M1442 and M280 are not required for mouse limb development. However, M280 is required for the development and/or maintenance of body size; M280 mice are significantly smaller than controls. M280 also harbors an "ultraconserved" sequence that is identical between human, rat, and mouse. This is the first report of a phenotype resulting from the deletion of an ultraconserved element. These studies highlight the importance of determining enhancer regulatory function by experiments that manipulate them in situ and suggest that some of an enhancer's regulatory capacities may be developmentally tolerated rather than developmentally required.

Development and morphogenesis of human wrist joint during embryonic and early fetal period.

The development of the human wrist joint has been studied widely, with the main focus on carpal chondrogenesis, ligaments and triangular fibrocartilage. However, there are some discrepancies concerning the origin and morphogenetic time-table of these structures, including nerves, muscles and vascular elements. For this study we used serial sections of 57 human embryonic (n = 30) and fetal (n = 27) specimens from O'Rahilly stages 17-23 and 9-14 weeks, respectively. The following phases in carpal morphogenesis have been established: undifferentiated mesenchyme (stage 17), condensated mesenchyme (stages 18 and 19), pre-chondrogenic (stages 19 and 20) and chondrogenic (stages 21 and over). Carpal chondrification and osteogenic processes are similar, starting with capitate and hamate (stage 19) and ending with pisiform (stage 22). In week 14, a vascular bud penetrates into the lunate cartilaginous mold, early sign of the osteogenic process that will be completed after birth. In stage 18, median, ulnar and radial nerves and thenar eminence appear in the hand plate. In stage 21, there are indications of the interosseous muscles, and in stage 22 flexor digitorum superficialis, flexor digitorum profundus and lumbrical muscles, transverse carpal ligament and collateral ligaments emerge. In stage 23, the articular disc, radiocarpal and ulnocarpal ligaments and deep palmar arterial arch become visible. Radiate carpal and interosseous ligaments appear in week 9, and in week 10, dorsal radiocarpal ligament and articular capsule are evident. Finally, synovial membrane is observed in week 13. We have performed a complete analysis of the morphogenesis of the structures of the human wrist joint. Our results present new data on nervous and arterial elements and provide the basis for further investigations on anatomical pathology, comparative morphology and evolutionary anthropology.

Limb development in the gekkonid lizard Gonatodes albogularis: A reconsideration of homology in the lizard carpus and tarsus.

Despite the attention squamate lizards have received in the study of digit and limb loss, little is known about limb morphogenesis in pentadactyl lizards. Recent developmental studies have provided a basis for understanding lizard autopodial element homology based on developmental and comparative anatomy. In addition, the composition and identity of some carpal and tarsal elements of lizard limbs, and reptiles in general, have been the theme of discussions about their homology compared to non-squamate Lepidosauromorpha and basal Amniota. The study of additional embryonic material from different lizard families may improve our understanding of squamate limb evolution. Here, we analyze limb morphogenesis in the gekkonid lizard Gonatodes albogularis describing patterns of chondrogenesis and ossification from early stages of embryonic development to hatchlings. Our results are in general agreement with previous developmental studies, but we also show that limb development in squamates probably involves more chondrogenic elements for carpal and tarsal morphogenesis, as previously recognized on the grounds of comparative anatomy. We provide evidence for the transitory presence of distal carpale 1 and intermedium in the carpus and tibiale, intermedium, distal centralia, and distal tarsale 2 in the tarsus. Hence, we demonstrate that some elements that were believed to be lost in squamate evolution are conserved as transitory elements during limb development. However, these elements do not represent just phylogenetic burden but may be important for the morphogenesis of the lizard autopodium.

[Numerical variants and congenital fusions of carpal bones]. / Variations numériques et synostoses congénitales des os du carpe.

The number of carpal bones may be increased or decreased by the fact of anatomical variants or true congenital anomalies. Numerical increment arises from additional or from split bones. Over twenty accessory carpal bones have been described but the commonest are the os centrale carpi, the os radiale externum, the triangular bone and the styloideum bone. Additional carpal bones usually result from a failure of fusion of their ossification centers. A congenital origin is not clearly established for all these ossicles. The scaphoid and lunate may split into two or three bones and several cases of bipartite hamulus of the hamatum have been reported. A carpus with only seven bones results from the congenital absence of a normal bone, which mainly affects the scaphoid, lunate and triquetrum, or from a synostosis between two carpal bones, usually the lunate and triquetrum. Congenital fusions originate from an absence of joint cavitation into the embryo and chondrification of the joint interzone. Numerical carpal variants are uncommon as independent entities but occur with a relative high frequency in association with complex malformations of the hand. These anomalies are detectable on plain radiographs of the wrist, but CT-scan and MR-Imaging are useful to differentiate bipartite and accessory bones from carpal fractures or posttraumatic injuries, carpal fusions having to be distinguished from bony ankylosis.

Morphometry by computerized three-dimensional reconstruction of the human carpal bones during embryogenesis.

Carpal skeleton shows drastic developmental changes during embryogenesis. At this stage, the cartilaginous matrices appear and later form models of the limb bones. The purpose of this study was to investigate the morphometry of carpal bones in humans during embryological development. We obtained digitalized histological serial sections of 18 human embryos and early fetuses from the Institute of Anatomy in Paris. Surfdriver and MSC.Patran software were used for three-dimensional reconstruction and morphometry. There was a strong correlation between the volume of the carpal cartilaginous structure and the size of the embryos (P<0.001) and an exponential correlation between the carpal volume and the percentage of volume presented by the proximal carpal row (P=0.005). According to inertia parameters, the geometry of carpal cartilaginous structure, initially plane, becomes curved during embryogenesis. Carpal bones growth follows non-homothetic transformation. The innovations in embryo reconstruction serve as new tool for scientific investigation. A hypothesis of carpal development is proposed.

Hand development and sequence of ossification in the forelimb of the European shrew Crocidura russula (Soricidae) and comparisons across therian mammals.

Hand development in the European shrew Crocidura russula is described, based on the examination of a cleared and double-stained ontogenetic series and histological sections of a c. 20-day-old embryo and a neonate. In the embryo all carpal elements are still mesenchymal condensations, and there are three more elements than in the adult stage: the 'lunatum', which fuses with the scaphoid around birth; a centrale, which either fuses with another carpal element or just disappears later in ontogeny; and the anlage of an element that later fuses with the radius. Carpal arrangement in the neonate and the adult is the same. In order to compare the relative timing of the onset of ossification in forelimb bones in C. russula with that of other therians, we built up two matrices of events based on two sets of data and used the event-pair method. In the first analysis, ossification of forelimb elements in general was examined, including that of the humerus, radius, ulna, the first carpal and metacarpal to ossify, and the phalanges of the third digit. The second analysis included each carpal, humerus, radius, ulna, the first metacarpal and the first phalanx to ossify. Some characters (= event-pairs) provide synapomorphies for some clades examined. There have been some shifts in the timing of ossification apparently not caused by ecological and/or environmental influences. In two species (Oryctolagus and Myotis), there is a tendency to start the ossification of the carpals relatively earlier than in all other species examined, the sauropsid outgroups included.

[The development of the wrist joint in the fetal period]. / El bilegi ekleminin fetal dönemdeki gelisimi.

OBJECTIVES: This study was designed to investigate the development and anatomical features of the wrist joint, particularly the scapholunate ligament and triangular disc in the fetal period and to identify possible congenital variations. METHODS: The study included 16 wrist joints of eight fetuses aborted at ages 8 to 14 weeks. The samples had no macroscopically discernible anomalies. Tissue specimens were fixed in 10% formalin solution, embedded in paraffin, and mounted on a microtome to obtain 5-micron sections in the coronal plane. Following staining with hematoxylin and eosin, conventional light microscopic examinations were performed. RESULTS: Organization of the carpal ligaments in the wrist joint began on the radial side in the 9th week. In the 10th week, the scapholunate ligament was formed; a membranous structure was observed, which lied from the interfacet prominence of the radius to the scapholunate ligament and divided the wrist joint into two cavities. The triangular disc formation began to appear at this stage. During the 11th and 12th weeks, the membranous structure underwent regression from the dorsal to the volar aspects, and at the end of the 14th week, the wrist joint became a single cavity. Also noted was the development of fibrous appearance of the scapholunate ligament and the triangular disc into fibrocartilage. Vascular areas were identified on the radial rather than the ulnar side of the scapholunate ligament, but vice versa for the triangular disc. Bicompartmental structure seemed to persist in the wrist joint of a 14-week-old fetus. CONCLUSION: In this study, we demonstrated that the scapholunate ligament and the triangular disc were not homogeneous in the fetal period in terms of vascularity and cellularity. We speculate that a plica-like membranous structure may persist in the wrist joint as a remnant of the fetal life. An accurate knowledge of the anatomy is necessary for the treatment planning and arthroscopic interpretation of the wrist joint.

Congenital absence of the 5th digital ray and its proximal segmental structures.

Limb reduction anomalies involving digits or parts of limbs are not uncommon. Most cases take the form of terminal transverse absence defects involving hypoplasia or aplasia of all structures distal to a particular level on a limb with relative preservation of the more proximal tissues. Longitudinal absence defects are a more rare form of limb reduction anomalies. Structures within one or more digital rays are typically involved. More proximal segmental tissues may also be affected with the most serious cases resulting in absence of the radius or ulna. We report a case of isolated, longitudinal absence of the 5th finger and its corresponding proximal segmental structures in a newborn infant. The embryology of limb development and possible etiologies for skeletal absence defects are summarized.

Anatomo-radiographic study on the osteogenesis of carpal and tarsal bones in horse fetus.

The aim of this study is to point out the time of appearance of the carpal and tarsal bones in the fetal horse, considering an estimated fetal age, to follow their morphological development through to birth, and to characterize possible abnormal shape and/or delay of their ossification. The right carpal and tarsal region of 140 equine fetuses of both sexes (71 males, 69 females) and different ages (from 70 to 340 days of gestation) were examined radiographically in order to identify the sites of ossification from their earliest appearance. The times of appearance of the sites of ossification of the carpal bones are chronologically stated for each bone.

[Embryology of the human carpal bones (triangular cartilage, central carpal bone, morphogenesis of the scaphoid)]. / Embryologie des os du carpe humain (cartilage triangulaire, os central du carpe, morphogenèse du scaphoïde).

Wax reconstructions according to Born's methods were performed from serial 10-micron sections of the wrists of human embryos (B. Tardif) to study the triangular cartilage and central bone of the carpus. A subsequent morphological study of the adult scaphoid bone was conducted in the light of embryological data. The triangular cartilage was observed in 4 of 38 carpi of embryos with a craniocaudal length of 40 to 69 mm, flatten between the ulna and triquetrum, on the inferior surface of the mesenchymal bud of the triangular ligament. The central bone of the carpus is constant in the embryo, between the inferior surface of the radial chondrification centre, capitatum, trapezium and trapezoid. In one case, the two wrists of the same embryo presented two central nuclei, leading to the distinction of two different formations:--the constant C2 embryonic central bone, trapped between capitatum, trapezoid and trapezium, which participates in the constitution of the scaphoid by fusion with the radial chondrification centre;--the C1 central bone, a rare supernumerary bone in adults, close to the inferolateral angle of the lunatum, on the dorsal surface of the carpus. These embryological data support. Westoll's theory concerning the filiation of the thoracic limb since the fin of crossopterygians, with deviation of the mechanical axis related to the development of weightbearing on the ground. The scaphoid bone must to be assimilated to a cube, but to an irregular tetrahedron, composed of two inverted pyramids joined by their bases. The inferior pyramid, articulating with he trapezium, trapezoid and capitatum, is concerned by morphological variations of the bone, which can present variable configurations between the two extreme morphotypes: the massive type and the strangulated type. The inferior pyramid, constituting the scaphoid, is derived from the central cartilage and presents the same relations. Variations of the volume of this inferior part of the bone are related to the more or less marked regression of this chondrification centre of the embryonic carpus. These variations of the bone can be expressed in terms of a scaphoid index, by calculating the relationship between the greatest dimension and the width of the narrowed portion.

Development of the human wrist joint ligaments.

BACKGROUND: Many studies have been published on the development of the human wrist joint, but scant attention has been given to the development of the wrist joint ligaments. Moreover, traditional description of wrist anatomy usually depict only the superficial capsular fibers of the wrist joint. The only ligamentous structure to receive much attention is the articular disc of the wrist joint, which has been described as a fibrocartilaginous structure extending from the medial edge of the lower end of the radius to the ulnar styloid process. METHODS: In the present report, we synthesize our observations in the wrist joint ligaments in 35 serially sectioned human embryonic and fetal hands (16 embryos and 19 fetuses). RESULTS: The interosseous intercarpal ligaments are organized from the mesenchyme, which, until O'Rahilly's stage 23, fills the intercarpal spaces. These ligaments are not individually distinguishable until the 9th week of development. The collateral ligaments begin to form in O'Rahillys's stage 22 and are completely formed by the end of week 10. The palmar radiocarpal and ulnocarpal ligaments (beginning with the palmar radiocarpal ligament) begin to form in O'Rahilly's stage 23 and are fully developed by the end of week 10. At this time, development of the dorsal radiocarpal ligament begins; this process is completed by the end of week 13. The articular disc which is initially formed of a single element, first appears in O'Rahilly's stage 23 and its organization is completed at week 10 of development. CONCLUSIONS: We establish the morphogenetic time-table of the wrist joint ligaments. Our descriptive findings may help explain carpal motion and the origin of wrist injuries.

[Evaluation of cartilaginous wrist development in the human during the prenatal period]. / Ocena Rozwoju Nadgarstka Chrzestnego u czlowieka w okresie prenatalnym.

The aim of the work was to assess the development of human chondral wrist in the prenatal period with regard to cartilaginous buds topography, histologic structure and development of article fissures in each month of intrauterine life. The performed examination covered 89 fetuses from 2nd to 9th month of prenatal life. Altogether 178 wrists were examined. The age of the fetuses was estimated on the clinical data, body mass, and crown-rump length base. Fetuses with developmental anomalies were excluded. At the beginning the material for microscopy was fixed and decalcified, next it was embedded in paraffin and cut on the microtome in a frontal plane. Preparations were stained by Van Gieson method, hematoxylin, and eosin. They were microscopied. I found that most of 2 month-old fetuses had 8 wrist bones buds. They were arranged in two rows: proximal and distal. Some of the examined fetuses had accessory bud that joined navicular bone during development process. Occasionally, 3, 4, 5, and 6 month-old fetuses revealed one chondral element with 2 or 3 differentiation foci in place of navicular, lunar and triangular bones. I disclosed no differences in histological development of wrist bone buds. (Fig. 1-4). There was a layer of thickened cells with mitotic figures at buds periphery in 2 and 3 month-old fetuses. A large amount of intercellular substance was in the central part. A reduced density of cells was seen in peripheral parts as well as in central parts, being viewed in intercellular substance, of buds in the 4th month of intrauterine life. Plane mesenchymal cells were observed on the surface of the buds, they created tracts forming layers, which may correspond to synovial membrane structure. The homogeneous substance staining yellow by Van Gieson method, what may be synovial membrane secretion, was found in 5 month-old fetuses. Reduction of cells from the periphery of buds had continued in 6th month. Cells forming buds resembled chondral, had light cytoplasm and central karyon, and fell into pairs. During further evolution it was observed that there was an increase of intracellular substance, formation of pairs and groups of chondral cells up to high differentiation. In 8th and 9th month of intrauterine life cells appeared like mature hyaline cartilage. Also chondral canaliculi including blood vessels were detected in the buds. Article fissures forming processes were observed already from 2nd month of intrauterine life and terminated their action in 5th month in the majority of fetuses. The evolution of distal radioulnar articular disc was seen, too. Mesenchyma being rich in cells was not differentiated in 2 month-old fetuses but during the evolution it changed into connective tissue band adhering to styloid process of ulna from one side and to head of radius from the other. Among forming article discs connective tissue fibres were found to be typical of chondral cells in 7, 8 and 9 month-old fetuses.

[Gibbous hand deformity--carpe bossu]. / Handrückenhöcker--Carpe bossu.

Fiolle (10) was the first to describe a bony protuberance of a carpometacarpal joint and named it carpe bossu. This anomalous anatomical condition occasionally becomes a--widely unknown--common clinical entity. The reasons are discussed. The clinical diagnosis can be confirmed by a lateral tangential radiograph. Discomfort and pain are rare and can be treated usually by conservative means, surgery is seldom indicated.

Developmental anatomy of the palmar aponeurosis and its relationship to the palmaris longus tendon.

The palmar aponeurosis and the palmaris longus tendon were examined in 33 hands of gestational age from 5 weeks to term. At 5 weeks both the longitudinal and transverse layers of the palmar aponeurosis and the palmaris longus tendon were present and in continuity. The palmaris longus tendon was absent in five specimens and in these the longitudinal fibers of the palmar aponeurosis blended into the antebrachial fascia. Otherwise the structure of the palmar aponeurosis was similar in the presence or absence of the palmaris longus tendon. The staining characteristics of the palmaris longus tendon were those of tendon whereas the palmar aponeurosis stained like fascia. These observations, as well as the fact that the palmar aponeurosis has never been reported to be absent, support the view of Kaplan that the palmar aponeurosis and the palmaris longus tendon are separate anatomic structures, which develop independently and are associated only by anatomic proximity.

[Scapholunate synostoses within the framework of congenital carpal synostoses]. / Synostoses radio-scapho-lunaires dans le cadre des synostoses carpiennes congénitales.

Modality of appearance in fetal life. Racial (certain) and congenital (probable) predisposing factors. X-ray discovery of radioscapholunate fusion after minor sprain of the wrist in a young 22 year old woman otherwise without past history. Functional study of the wrist. Analysis of six similar observations reported to date.

Ossification in the hand and foot of the pigtail macaque (Macaca nemestrina). II. Order of appearance of centers and variability in sequence.

The order of appearance of the carpals, tarsals and secondary epiphyseal centers in the hand-wrist and foot-ankle regions of the fetal and infant pigtail macaque (Macaca nemestrina) was reconstructed using a cross-sectional sample of 127 animals and a longitudinal one of 14 animals. Comparison of the most common sequence in the monkey with that described in the human studies showed major interspecific differences in the order of appearance of several groups of centers, particularly those involving the thumb and great toe. The monkey displays a degree of sequence variability equivalent to that documented by the human longitudinal data, with certain centers markedly variable in timing and/or order of appearance. The evidence from related animals suggests a strong genetic component underlying some of the variable sequences observed, as has been reported in the human studies. The demonstrated variability in both timing and sequence precludes the use of specific centers in the determination of gestational age in fetuses of unknown conception date.

Prenatal origins of carpal fusions.

As shown in 138 embryos and fetuses in the 40-285 mm crown-rump length range, carpal and carpal-metacarpal "fusions" arise from incomplete separation of the cartilaginous precursors rather than from failure of initiation, thus accounting for the "fusions" seen in postnatal radiographs and the grooves that are evident enough in adult fusions. Radiographs selected from over 20,000 apparently normal individuals provide postnatal counterparts for the prenatal examples shown in histological sections.

[The development of the triangular ligament in man]. / Note sur le developpment du ligament triangulaire chez l'homme

The origin of the carpal articular disc has been studied in serial sectioned embryonal and fetal hands. In particular the complex; ulnar styloid process--triangular disc--carpal joint has been considered. In this development a relation is brought about between the so-called lig. subcruentum and the prestyloid recess. It has to be emphasized, that both pre-styloid recess and pisotriquetral joint space originate as isolated spaces.