Sphenomandibular ligament and degenerating Meckel's cartilage revisited: Sequential variations with temporal bone deformity for ligament attachment in near-term human fetuses.

BACKGROUND: The sphenomandibular ligament (SML) is considered to originate from Meckel's cartilage (MC). However, no study has examined how the os goniale contributes to SML development. METHODS: Semiserial histological sections of heads from 18 near-term fetuses at 27-40 weeks of gestation were examined. OBSERVATIONS: The os goniale and the anterior process of the malleus (AP) provided a long, bar-like membranous bone complex that passed through the petrotympanic and tympanosquamosal fissures. Notably, the AP-goniale complex is sometimes elongated inferiorly to join the SML (n = 4 specimens). Along the complex in the bone fissures, a degenerating MC was often present (n = 12). With (n = 6) or without (n = 3) the MC remnant, the tympanic bone (TYB) protruded inferomedially near the tympanosquamosal fissure, and it sometimes continued to a cartilaginous SML (n = 3). The temporal bone squamosa or petrosa provided a similar bony process approaching the SML. The middle meningeal artery often ran between the sphenoid and petrosa. CONCLUSIONS: Most of the specimens (n = 15) exhibited a sequential change from a cartilaginous SML as a continuation of the MC remnant to the ligament after the disappearance of the cartilage. The degenerating MC appeared to cause transformation from the AP-goniale complex and/or TYB to "another ligament" that replaced the usual SML at the upper part. Near the MC remnant, a similar transformation was also suggested on the squamosa or petrosa. The sphenoid spine appeared to originate often from the sphenoid ala major but sometimes from the TYB.

Localization of macrophages and dendritic cells in human thoracic lymph nodes: An immunohistochemical study using surgically obtained specimens.

Both dendritic cells (DCs) and macrophages are bone marrow-derived cells that perform antigen presentation. The distribution of DCs and CD68-positive macrophages were immunohistochemically examined in 103 thoracic nodes obtained from 23 lung cancer patients (50-84 years old) without metastasis. Among three antibodies tested initially-CD209/DCsign, fascin, and CD83-DCsign was chosen as the DC marker. For comparison, 137 nodes from 12 patients with cancer metastasis were also examined histologically. In patients without metastasis, DCs were found as (1) clusters along the subcapsular sinus and in a border area between the medullary sinus and cortex (mean sectional area of multiple nodes at one site, 8.4%) and, (2) rosette-like structures in the cortex (mean number in multiple nodes at one site, 20.5). Notably, DC clusters and rosettes contained no or few macrophages and were surrounded by smooth muscle actin (SMA)-positive, endothelium-like cells. The subcapsular linear cluster corresponded to 5%-85% (mean, 34.0%) of the nodal circumferential length and was shorter in older patients (p = 0.009). DC rosettes, solitary, or communicating with a cluster, were usually connected to a paracortical lymph sinus. Few differences were found between nodes with or without metastasis, but DC cluster sometimes contained abundant macrophages in cancer metastasis patients. The subcapsular DC cluster is not known in the rodent model, in which the subcapsular sinus is filled with macrophages. This quite different, even complementary, distribution suggests no, or less, cooperation between DCs and macrophages in humans.

Development and growth of the calcaneal tendon sheath with special reference to its topographical relationship with the tendon of the plantaris muscle: a histological study of human fetuses.

BACKGROUND AND PURPOSE: The calcaneal tendon sheath has several vascular routes and is a common site of inflammation. In adults, it is associated with the plantaris muscle tendon, but there are individual variations in the architecture and insertion site. We describe changes of the tendon sheath during fetal development. MATERIALS AND METHODS: Histological sections of the unilateral ankles of 20 fetuses were examined, ten at 8-12 weeks gestational age (GA) and twelve at 26-39 weeks GA. RESULTS: At 8-12 weeks GA, the tendon sheath simply consisted of a multilaminar layer that involved the plantaris tendon. At 26-39 weeks, each calcaneal tendon had a multilaminar sheath that could be roughly divided into three layers. The innermost layer was attached to the tendon and sometimes contained the plantaris tendon; the multilaminar intermediate layer contained vessels and often contained the plantaris tendon; and the outermost layer was thick and joined other fascial structures, such as a tibial nerve sheath and subcutaneous plantar fascia. The intermediate layer merged with the outermost layer near the insertion to the calcaneus. CONCLUSION: In spite of significant variations among adults, the fetal plantar tendon was always contained in an innermost or intermediate layer of the calcaneal tendon sheath in near-term fetuses. After birth, mechanical stresses such as walking might lead to fusion or separation of the multilaminar sheath in various manners. When reconstruction occurs postnatally, there may be individual variations in blood supply routes and morphology of the distal end of the plantaris tendon.

The so-called absorption process of the pulmonary vein into the left atrium of the heart: a histological study using human embryos and fetuses.

BACKGROUND: Embryonic pulmonary veins (PVs) are believed to be absorbed into the left atrium (LA) to provide an adult morphology in which "four" veins drain separately into the atrium. MATERIALS AND METHODS: Serial histological sections were obtained from 27 human embryos and fetuses. RESULTS: Between 5 and 6 weeks, the four PVs joined together to form a trunk-like structure (initial spatium pulmonalis) that was larger than the initial LA (two-ostia pattern). The cardiac nerves ran inferiorly along the posterior aspect of the four veins, as well as the spatium. At and until 7 weeks, the cardiac nerves were concentrated to elongate the nerve fold, and the latter separated the left PV trunk from the expanding LA (left spatium). Similarly, the right PV opened to a thick and deep LA recess (right spatium). At 8-12 weeks, depending on the growth of the LA, the opening of the left and right PVs became distant, and the spatium was elongated transversely. The left spatium was enlarged to open widely to the proper left atrium in contrast to the right spatium pushed anteriorly by the right atrium. The three-ostia pattern was transiently observed because of the lost delimitation between the left spatium and proper atrium. The myocardium was thin in the left spatium behind the left atrial nerve fold, whereas the right spatium was tube-like with a thick myocardium. CONCLUSIONS: The four-ostia pattern seemed to be established at birth due to a drastically increased venous return from the lung, resulting in a flat smooth left atrial posterior wall.

Identification of potential predictive biomarkers and biological pathways and the correction with immune infiltration in the activation of Crohn's disease.

Crohn's disease (CD), a subtype of inflammatory bowel disease (IBD), has increasing prevalence in the world. Due to the lack of cure strategy, most patients with CD develop progressive disease companying with a series of serious complications. Therefore, exploring molecular mechanism differences between active and inactive CD will help in the screening of predict markers and therapeutic targets. In this study, we analyzed differentially expressed genes (DEGs) and molecular pathways through between active and inactive CD patients. In addition, the abundance of 22 immune cell types were assessed by using the CIBERSORT. The hub DEGs were screened out by the CytoHubba in Cytoscape, followed by the least absolute shrinkage and selection operator (LASSO) regression. Finally, the clinical predictive model was constructed by binary logistic regression model. The diagnostic efficacy was tested by receiver operating characteristic (ROC) curve and verified in independent datasets. The results showed that there were 137 DEGs between the active and inactive CD. Most of them were involved in regulating the immunity process. In addition, the decreased abundance of CD8 T cells and the increased abundance of M0, M1 macrophages, and neutrophils were closely related to CD activation. CXCL9, C3AR1, IL1B, and TLR4 were the hub gene and can be applied to the prediction of CD activation. Our results provided important targets for the prediction of CD activation and the selection of therapeutic targets.

Major change in morphology of the talofibular ligaments during fetal development and growth.

BACKGROUND AND PURPOSE: Ankle sprain is often attributed to damage of the anterior and posterior talofibular ligaments (ATFL, PTFL). We compared the morphology of these ligaments in fetuses of different gestational ages (GAs) with the horizontal configuration in adults. MATERIALS AND METHODS: Histological sections of unilateral ankles were examined in 22 fetuses, 10 at GA of 9-12 weeks and 12 at GA of 26-39 weeks. RESULTS: At a GA of 9 to 10 weeks, the ATFL and PTFL consisted of horizontally running straight fibers. The initial ATFL appeared as a thickening of the capsule of the talocrural joint, although the initial PTFL was distant from this joint. Until a GA of 12 weeks, the talus and fibula were separated by an expanding joint cavity. Thus, the initial horizontal ligaments were "pulled" in a distal direction. The distal parts of the ligaments consisted of thin collagenous fibers that had an irregular array, whereas the short proximal parts had thick fibers and a horizontal array. In near-term fetuses, the ligaments contained no horizontal fibers. The ATFL had a wavy course around the thick synovial fold, and was exposed to the joint cavity along the entire course; the distal part was thinner than the proximal part. The PTFL was bulky and consisted of fibers with an irregular array. Therefore, the morphology in a near-term fetus was quite different from that in adults. CONCLUSION: The horizontal and straight composite ankle fibers in adults apparently result from postnatal reconstruction, depending on mechanical demand.

Growth in fetuses of the constrictor pharyngis superior with special reference to its meeting with the buccinator: an embryological basis of adult variations in palatopharyngeal anatomy.

PURPOSE: The constrictor pharyngis superior (CPS) initially develops along the posterior wall of the pharyngeal mucosal tube, whereas, during the early phase, the buccinators (BC) are far anterolateral to the CPS. The process and timing of their meeting during fetal growth have not been determined. METHODS: The topographical relationship between the growing BC and CPS was assessed in histological sections from 22 early- and mid-term fetuses of approximate gestational age (GA) 8-16 weeks, and eight late-term fetuses of approximate GA 31-39 weeks. RESULTS: At 8-9 weeks, the palatopharyngeus appeared to pull the CPS up and forward. Until 11 weeks, the CPS was attached to the hamulus of the pterygoid (pterygopharyngeal part). Until 13 weeks, the CPS extended anterolaterally beyond the hamulus to meet the BC. Some BC muscle fibers originated from the oral mucosa. Notably, by 30 weeks, the CPS-BC interface had become covered by or attached to the palatopharyngeus. Muscle fibers of the palatopharyngeus, however, were thinner than those of the CPS and BC. At and near the interface, BC muscle fibers tended to run along the left-right axis, whereas those of the CPS ran anteroposteriorly. A definite fascia (i.e., a future pterygomandibular raphe) was usually absent between these muscles in fetuses. CONCLUSIONS: The excess anterior growth of the CPS with its subsequent degeneration might cause individual anatomical variations in composite muscle bundles of the palatopharyngeus-CPS complex or palatopharyngeal sphincter. A tensile transduction from the BC to the CPS through the raphe seemed unnecessary for cooperative suckling and swallowing after birth.

Anatomy of the vitelline vein remnant in human embryos and fetuses.

PURPOSE: To demonstrate the entire course of the human vitelline vein (VV) in specimens after degeneration of the yolk sac. METHODS: Sagittal and horizontal histological sections from 8 embryos and 19 fetuses (gestational age approximately 6-12 weeks; crown-rump length 11-61 mm) were examined. RESULTS: Two types of VV remnants were observed: a long VV on the right superior side of the mesentery of the jejunum (VV1) and a short VV on the left inferior side of the mesentery (VV2). The VV1, observed in 12 specimens, was 20-30 microns in diameter and ran dorsally between the right liver lobe and the jejunum, subsequently merging with an initial superior mesenteric vein on the pancreatic head immediately below the superior portion of the duodenum. The VV2, observed in four specimens, passed dorsally between loops of the ileum on the left side of the mesentery of the ileum and connected to the mesentery. Many of the VVs did not originate from the umbilical cord but suddenly started in the sack of physiological herniation. At 10-12 weeks, after herniation, the VVs originated from the umbilicus and were involved by the expanding greater omentum. CONCLUSIONS: The right-sided and left-sided VVs seemed to correspond to right and left VV remnants, respectively, and both took an upstream course outside the mesentery of the jejunum and ileum. The right VV upstream portion was likely to disappear later than the left one, but the timing of degeneration varied greatly among individuals, depending on the topographical relationship between the right liver lobe and the jejunum.

The Allantois and Urachus: Histological Study Using Human Embryo and Fetuses.

Relatively little is known about allantois and urachal development in early humans.Serial sagittal histological sections from eight human embryos and fetuses were examined to determine allantois development.At gestational age 6-7 weeks, the primitive allantois consists of an enlarged tube located between the umbilical cord and abdominal cavity, whereas the urachus is not yet developed. At 8 weeks, the allantois gradually withdraws from the distal to the proximal end of the umbilical cord, and both the proximal allantois and the rectum (hindgut) start to develop into the cloaca. At 10 weeks, the allantois was located mostly in the abdominal cavity.The urachus forms from the distal end of the allantois and develops into a closed fibrous cord between the base of the urinary bladder and the umbilicus. The urogenital sinus forms from the proximal end of the allantois.

Delayed development of vacuoles and recanalization in the duodenum: a study in human fetuses to understand susceptibility to duodenal atresia/stenosis.

ObjectiveWe compared the cross-sectional areas of the duodenum to the distal small intestine during early gestation to determine if there is a difference in age for recanalization.MethodsSerial sagittal sections of six fetuses of gestational age (GA) 8-10 weeks were examined morphologically to compare the degree of recanalization of the duodenum with to the more distal small intestine.ResultsAt GA 8-9 weeks, the duodenum had more epithelial plugs and vacuoles with no or narrower spaces compared to the distal small bowel. Quantitative assessment at GA 10 weeks showed that the cross-sectional area of the duodenal cavity was significantly less than the distal small bowel.ConclusionThe development and recanalization of vacuoles in the duodenum occurs later than the jejunum and ileum may be involved in the more frequent development of atresia/stenosis of the duodenum compared to more distal gastrointestinal tract.

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.

Fetal development of the thoracolumbar fascia with special reference to the fascial connection with the transversus abdominis, latissimus dorsi, and serratus posterior inferior muscles.

PURPOSE: The three-layered thoracolumbar fascia (TLF) encapsulates the erector spinae and the quadratus lumborum and has been a major concern for physical therapists. However, knowledge of its prenatal development and growth is limited. METHODS: Histological examination of 25 embryos and fetuses at 6-37 weeks (CRLs, 15-310 mm). RESULTS: At the posterior end, the abdominal muscles continued toward an initial posterior layer of the TLF (pTLF) at 6 weeks, but the connection became narrow and limited to the obliquus externus aponeurosis until near term. The middle layer of the TLF (mTLF) appeared as a posterior continuation of the transversalis fascia at 9 weeks and, depending on a mechanical demand for the vertebral column extension near term, it grew as a thick intermuscular septum between the iliocostalis and quadratus lumborum. Thus, the mTLF lateral end changed from the abdominal wall to the back or pTLF. The serratus posterior inferior originated from the pTLF after 9 weeks, but a connection of the latissimus dorsi with the fascia was established much later. Near term, the gluteus maximus was attached to an aponeurosis covering the multifidus behind the sacrum. Therefore, the pTLF extended to cover the gluteal muscles. CONCLUSION: We rejected the hypothesis that the mTLF develops as a marginal tissue between the primitive epaxial and hypaxial muscles. This study seemed to be the first report showing a fact that, within prenatal life, a drastic change is likely to occur in interfascial connections and their topographical relation to muscles; the TLF might be the best sample.

Human orbital muscle in adult cadavers and near-term fetuses: its bony attachments and individual variation identified by immunohistochemistry.

PURPOSE: To compare fetal and adult morphologies of the orbital muscle (OM) and to describe the detailed topographical anatomy in adults. METHODS: Using unilateral orbits from 15 near-term fetuses and 21 elderly cadavers, semiserial horizontal or sagittal paraffin sections were prepared at intervals of 20-100 µm. In addition to routine histology, we performed immunohistochemistry for smooth muscle actin. RESULTS: At near term, the OM consistently extended widely from the zygomatic bone or the greater wing of the sphenoid to the maxilla or ethmoid. Thus, it was a large sheet covering the future inferior orbital fissure. In contrast, the adult OM was a thin and small muscle bundle connecting (1) the greater wing of the sphenoid to the maxilla (11/19 cadavers), (2) the lesser wing of the sphenoid to the maxilla (5/19) or the greater wing (3/19). The small OM was likely to be restricted within the greater wing (5/19 cadavers) or the maxilla (3/19). Two of these five types of OM coexisted in eight orbits. OM attachment to the lesser wing was not seen in fetuses, whereas ethmoid attachment was absent in adults. CONCLUSIONS: The lesser wing attachment of the OM seemed to establish after birth. A growing common origin of the three recti was likely involved in "stealing" the near-term OM attachment from the ethmoid. The strong immunoreactivity of remnant-like OM in the elderly suggests that OM contraction is still likely to occur against the increased flow through a thin vein. However, the contraction might have no clinical significance.

Left/right difference in the course and division of the pulmonary arterial branches in the lung upper lobe: A study using human embryos and early fetuses.

Although left/right differences in a configuration of the pulmonary artery (PA) and its branches are well known, there is little information as to when and how such differences are established. Examination of serial sagittal sections of 25 embryos and fetuses at 6-7 weeks of gestation demonstrated that, at O'Rahilly stages 18-20, the right earliest first branch of PA originated in the anterior side of the upper lobar bronchus and overlay the upper bronchi, in contrast to the left branch which was located posteriorly and constricted medially by the upper posterior bronchus B1 + 2b. The right earliest branch was most likely to correspond to the future superior trunk, while the left branch might be a lingual artery. At stages 21-23, the upper posterior parenchyma was still underdeveloped in the left lung, since the ductus arteriosus and the left common cardinal vein seemed to make the left upper thoracic cavity narrow. Conversely, in the right lung, the thick S2 seemed to require a double arterial supply from both the superior and inferior arterial trunks. On the left, A3 originated at the lung apex and took a long descending course along the lung anterior surface. This high position of A3 might soon be corrected by an increased volume of S3. Overall, in contrast to the lower and middle lobes, early-developed branches of the PA did not accompany upper segmental and subsegmental bronchi. A mechanism "differential growth" seemed to explain how to correct the fetal morphology to provide the adult morphology with variations.

The incudopetrosal joint of the human middle ear: a transient morphology in fetuses.

In spite of the amount of research on fetal development of the human middle ear and ear ossicles, there has been no report showing a joint between the short limb of incus and the otic capsule or petrous part of the temporal bone. According to observations of serial histological sections from 65 embryos and fetuses at 7-17 weeks of development, the incudopetrosal joint exhibited a developmental sequence similar to the other joints of ossicles, with an appearance of an interzone followed by a trilaminar configuration at 7-12 weeks, a joint cavitation at 13-15 weeks and development of intraarticular and capsular ligaments at 16-17 weeks. These processes occurred at the same time or slightly later than any other joint. Thus, the joint development might coordinate with vibrating ossicles in utero. The growing short limb of incus appeared to accelerate an expansion of the epitympanic recess of the tympanic cavity. Additional observations of five late-stage fetuses demonstrated the incudopetrosal joint located in the fossa incudis joint changing to syndesmosis. Consequently, a real joint with a cavity existed transiently between the human neurocranium and the first pharyngeal arch derivative (i.e. incus) in contrast to the tympanostapedial joint or syndesmosis between the neurocranium and the second arch derivative. The newly described joint might have an effect on the widely accepted primary jaw concept: the mammalian jaw should thus have been created within the first pharyngeal arch, although the connection with neurocranium by the stapes is of a different origin.

Three-dimensional analysis of the segmental arrangement of lower lung lobes in human fetuses: is this arrangement a miniature version of adult morphology?

Knowledge of the lung segment system is essential for understanding human anatomy and has great clinical relevance. The arrangement of 11 segments, including the S* or subsuperior segment, and its individual variations, are considered to be the same in fetal and adult lungs. The present study assessed the topographical anatomy of lower segmental and subsegmental bronchi by computer-assisted three-dimensional imaging of serial sagittal sections of both lungs of 22 embryos and fetuses of gestational age 6-7 weeks (crown-rump length 15.0-28.5 mm). Long inferior courses of B8b (basal) and B10c (medial) were observed in sagittal sections of both lungs. B8a (lateral) and B10b (lateral) in the right lungs were consistently underdeveloped, with S9 occupying most of the lateral half of the lower lobe. In some samples, B6b (lateral) did not reach the lateral surface. The lateral dominance of S9 was also seen in the left lungs. Some B* candidates were present, but B7 candidates were absent. Lateral and posterior expansions of S6b, S8a and S10b to cover S9 were observed in additional midterm and near-term lung sections, indicating that the original S9 dominance was 'corrected' by an increase in lung volume. Delayed growth of the lower lateral subsegments might induce mechanical stress, resulting in aberrant notches or fissures, such as those separating an independent posterior lobe. The segmental arrangement of fetal lungs was not stable, but was altered over a long fetal period after the complete subsegmental division of the bronchi, except for the minor bronchi B* and B7.

Umbilicus and the rectus sheath: a study using human fetuses.

PURPOSE: The newborn umbilicus is provided by a fibrous ring after closure with a scar at the bottom. Since it is believed to be embedded in the linea alba, a specific connection with the rectus sheath was not yet hypothesized for the umbilicus. However, there are no or few descriptions about the development and growth. METHODS: We histologically examined 28 fetuses at 8-40 weeks: 6 fetuses at 8 weeks, 12 at 10-14 weeks and 10 at 31-40 weeks. RESULTS: An initial rectus sheath issued a linear mesenchymal condensation toward the umbilical cord at 10-14 weeks and, an established sheath provided a fibrous band around the umbilical cord at 31-40 weeks. The rectus sheath margins made an acute turn toward the skin at the superior and lateral rims of umbilicus and dispersed into a loose tissue of the cord. In contrast, the sheath margin changed its direction gradually to the superficial side at the inferior rim and inserted at a border between the skin epidermis and a mesothelium-like covering of the cord. The developing umbilical ring contained no or few elastic fibers. CONCLUSION: Instead of the underdeveloped linae alba, the rectus sheath seemed to be tightly connected with the umbilicus at birth. Rather than an expected elasticity, the rectus muscle contraction was likely to play a critical role in the closure after birth. Via the umbilical ring, the fetal rectus sheath also seemed to tightly connect with the skin at the inferior rim of umbilicus.

Magnetic resonance imaging features of fibromas and giant cell tumors of the tendon sheath: differential diagnosis.

PURPOSE: The clinical and imaging characteristics of fibromas of the tendon sheath (FTS) closely resemble those of giant cell tumors of the tendon sheath (GCTTS). We aimed to study MRI features of FTS and GCTTS to distinguish the two entities and improve their differential diagnosis. MATERIALS AND METHODS: We retrospectively analyzed data from 18 patients (9 men, 9 women; age, 17-62 years) and 24 patients (13 men, 11 women; age, 15-67 years) treated between May 2011 and May 2016, with histologically confirmed FTS and GCTTS, respectively. Specific MRI features of the two groups were compared using the independent sample t tests and chi-square tests. RESULTS: FTS exhibited round or oval shapes. Proton-weighted images (PDWI) showed heterogeneous hypointensity that appeared striped or disordered and was located in the lesion center. Enhanced scans demonstrated asymmetrical signal in the foci. GCTTS mostly exhibited a lobulated or casting mold pattern, with a hypointense ring on PDWI. The hypointense components appeared granular/flaky or separated, sometimes behaving as a uniform signal on PDWI. Significant differences in the following features were observed between the two groups: lesion morphology (p < 0.001); imaging features on PDWI, including whether the signal is homogeneous (p < 0.001); the presence of a hypointense ring (p = 0.006); the location and morphology of hypointensity (p < 0.001); bone absorption (p = 0.008); enhancing pattern (p = 0.008); and whether the tumor crossed the joint (p = 0.026). CONCLUSIONS: FTS and GCTTS demonstrate distinctive MRI features, which can be used for differential diagnosis with sensitivities, specificities, and diagnostic accuracies of 83-100%, 29-79%, and 60-89%, respectively. KEY POINTS: • Fibromas and giant cell tumors of the tendon sheath have distinct features on MRI, including differences in lesion morphology and intensity patterns, which can be used for differential diagnosis. • Among other signs, GCTTS are more uniform than FTS, and FTS have a striped or disordered pattern. • Tumors were classified with 90% accuracy into either FTS or GCTTS based on a combination of two features: homogenous signal and hypointensity shape on PDWI.

Topographical anatomy of the intestines during in utero physiological herniation.

Because most malrotations of the small intestine are thought to occur during repackaging, the location of the intestine should vary less during physiological herniation than afterward. Examination of serial sagittal sections of 27 embryos and fetuses (gestational age 6-9 weeks; crown-rump length 15-45 mm) during herniation showed that the jejunum and ascending colon passed through a small opening of the hernia sac at the levels of the stomach and pancreas in 16 specimens. Below the pancreas, a definite mesentery extended between the ascending and descending colon in the abdominal cavity. In the other 11 specimens, the descending colon passed through an opening of normal size and ran posteriorly along the urinary bladder, so the entire ilium, ascending colon, and transverse colon entered the sac. In these specimens, the duodenojejunal junction was usually situated in a window of the mesentery of the colon (internal herniation). The descending colon was observed at an outside location more frequently in earlier specimens. In contrast to our working hypothesis, the locations of the intestine were abnormal in 40.7% (11/27) of samples. In addition, no abnormal colon was observed in any of the seven specimens after repackaging. An outside location of the descending colon was not directly associated with malrotation because recovery was likely. However, the delayed development of the inferior mesenteric arterial branches could cause failure, including death in utero, during or after the repackaging associated with physiological herniation. Clin. Anat. 31:583-592, 2018. © 2017 Wiley Periodicals, Inc.

Fetal Development of Human Oral Epithelial Pearls With Special Reference to Their Stage-Dependent Changes in Distribution.

OBJECTIVE: To access detailed distribution and age-dependent changes of oral epithelial pearls. DESIGN: Investigation and analysis with human fetal serial sections. SETTING: Institute of Embryology. METHODS: This study examined serial frontal sections of the upper and lower jaws of 19 human fetuses at 12 to 18 weeks and of the lower jaws of four late-stage fetuses. RESULTS: The upper jaw contained more than 20 midline and more than 60 lateral pearls greater than 20 µm in diameter, whereas the lower jaw contained fewer than 30 pearls of the same size. Midline pearls in the upper jaw were often cylindrical or rugby-ball shaped, whereas all pearls in the lower jaw were small and spherical. Epithelial pearls in the upper jaw started developing along the upper midline until 12 weeks; lateral pearls and additional midline pearls (or strictly, paramedian pearls) developed until 15 weeks. In the lower jaw, however, pearl development started at 18 weeks and was almost always from the dental lamina. Some of the fetuses assessed had an open nasopalatine canal without a duct, but there was no fibrous connection between this canal and pearls. Similarly, the lip frenulum or incisive suture was not connected with these pearls. CONCLUSION: The timing and sequence of development suggest that postfusion rupture of the palate by midline pearls was unlikely.