Vermiform Appendix During the Repackaging Process from Umbilical Herniation to Fixation onto the Right Posterior Abdomen: A Study of Human Fetal Horizontal Sections.

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.

Cystic Crypt Changes in Midgestational Human Vermiform Appendix: An Unrecognized Transient Histologic Feature.

INTRODUCTION: Lewis and Huff briefly described the presence of "microcystic cryptitis" in some of fetal vermiform appendices (VA) at autopsy. We further characterized these crypt changes (CC), their timing of occurrence, and tested their association with infection/inflammatory conditions. METHODS: Hematoxylin and eosin-stained slides of 345 VA were evaluated for the presence or absence of CC and their different morphologies. Autopsy reports were reviewed for evidence of amniotic fluid or fetal systemic infection and placental inflammatory conditions. RESULTS: Crypt dilatation with or without irregularity of the lumen, crypt dilatation with semiattenuated epithelium, intraluminal apoptotic debris and inflammatory cells, especially eosinophils, and foci of swirled spindled cells with calcifications or multinucleated giant cells were observed, either alone or in combination, in at least 58.5% (202/345) of the VA. CC began to appear at 17 weeks, peaked at 20 to 25 weeks (with up to 82% of VA exhibiting CC during this time), and followed by a steady decline beyond 28 weeks gestation. χ2 test of independence showed no significant association (P = .435; >0.05) between the presence and absence of CC and infection status of the fetus or placenta. CONCLUSION: The underrecognized CC of the developing fetal vermiform appendix (VA) showed distinct temporal pattern of occurrence and did not seem to be affected by the presence or absence of infection, which so far favored their being a part of the normal gut developmental process.

Anatomical variants and pathologies of the vermix.

The appendix may demonstrate a perplexing range of normal and abnormal appearances on imaging exams. Familiarity with the anatomy and anatomical variants of the appendix is helpful in identifying the appendix on ultrasound, computed tomography, and magnetic resonance imaging. Knowledge of the variety of pathologies afflicting the appendix and of the spectrum of imaging findings may be particularly useful to the emergency radiologist for accurate diagnosis and appropriate guidance regarding clinical and surgical management. In this pictorial essay, we review appendiceal embryology, anatomical variants such as Amyand hernias, and pathologies from appendicitis to carcinoid, mucinous, and nonmucinous epithelial neoplasms.

The vermiform appendix: a review.

New research on the vermiform appendix has shed light on its function. In further understanding the function of the appendix, this information should not negatively impact the clinical judgment in the event of appendicitis. Although the appendix and its pathology have been noted for centuries, it still presents a challenge in the operating room. The most common emergency surgical procedure performed is an appendectomy. Its highly variable position within the abdomen can cause confusion for clinicians. However, improved imaging modalities have heightened the physician's ability to diagnose disease of this organ. This article reviews germane literature regarding the human vermiform appendix.

Pseudoapêndice caudal associado a pé torto congênito: relato de caso / Caudal pseudo tail associated with congenital clubfoot: case report

O apêndice caudal é uma rara anomalia congênita, localizada na região lombossacral. Classifica-se, segundo Dao e Netsky, em pseudoapêndice e apêndice caudal verdadeiro,com implicações prognósticas e terapêuticas.O apêndice caudal pode estar associado a outras anormalidades congênitas, sendo necessários exame físico detalhado e exames de imagem para diagnóstico e tratamento precoce das doenças concomitantes. Os autores relatam um caso de pseudoapêncice caudal lombossacro (fibrolipoma congênito), associado a pé torto congênito, em uma criança submetida a tratamento cirúrgico excisional do pseudoapêndice. Fez-se revisão da literatura sobre casos semelhantes e não foi encontrada descrição da associação com pé torto congênito.

Development of the vermiform appendix during the fetal period.

This study aimed to determine the location and development of the vermiform appendix (VA) in terms of morphometry. It was carried out on 80 human fetuses that exhibited neither external pathology nor anomaly and whose gestational ages were between 10 and 40 weeks. The location of the VA and cecum was established. Total VA diameter, lumen diameter, wall thickness, serosa, muscularis and mucosa thickness were measured on microscope slides. The VA was almost always observed in the subcecal region during the fetal period. The length of the VA and the attachment length of the meso-appendix to the VA increased with the gestational age. Lymphocyte aggregation was first seen at the 17th week of the fetal period. Positive and meaningful correlation was found between gestational age and morphometric parameters of the VA. A significant difference was found between the genders in the thickness of mucosa, which was larger in girls (p<0.05). When the proximal, median and distal parts were compared, the thickness of serosa between the proximal and distal parts was also significantly different (p<0.05). The present study has revealed that the VA matures in the second trimester during the fetal period. Furthermore, the morphologic development of the VA is almost uniform from the proximal to distal part.

Peyer's patches are precocious to the appendix in human development.

PP are first visible at approximately 15.5 wk gestation after which there is a rapid spurt in the development and maturation of lymphoid follicles so that at any given point of time new foci of PP development are continuously formed at a rapid rate. Addition of rows of follicles results in the formation of a PP. Immature PP of younger fetuses have a spongy structure in contrast with the compact lymphoid follicles of mature PP of older fetuses. Immunocytochemical studies reveal that there is a subtle gradation in the expression of lymphocyte surface markers with increasing fetal age. Expression of antigenic markers occurs in an ordered sequence viz. HLA - DR, CD19 (B cell population), CD9 (pre-B cells), CD3 T lymphocytes, CD4 helper / inducer lymphocytes, the CD8 suppressor / cytotoxic cells and lastly, the CD57 Natural Killer cells. The antigens are expressed first on lymphocytes of PP and thereafter in those of the appendix. Our findings clearly demonstrate that the approximately 5 wk fetal period from 17.5 wk to 22 wk represents a major growth phase in the development of surface markers of lymphocytes in the mucosal immune system of the gut.

Growing of caecum and vermiform appendix during the fetal period.

OBJECTIVE: The aim of this study is to investigate the growing of the caecum and the vermiform appendix during the fetal period in human fetuses and the relation between growing and shape of the caecum and the localization of the vermiform appendix. METHODS: 40 male and 40 female externally normal-looking fetuses were studied between 10 and 40 weeks of gestation and were subdivided into fetuses of the 1st, 2nd, and 3rd trimesters and full-term fetuses. The parameters of interest included covering of the caecum with peritoneum, shape of the caecum (long tube, symmetric saccule, asymmetric saccule, extremely large right side--atypical), axial length and width of the caecum localization of the vermiform appendix, length of vermiform appendix and length of the meso-appendix. RESULTS: There was a difference in covering of the caecum with peritoneum between males and females; the caecum was predominantly tube shaped during the fetal period, with the asymmetric saccule towards the end of the fetal period; the localization of the vermiform appendix was subcaecal (39%) during the fetal period and postileal (34%) in female fetuses and subcaecal (48%) in male fetuses--the localization of the vermiform appendix changed according to the caecum shape during the fetal period; we found significant differences in the measurements of vermiform appendix, meso-appendix, and caecum among 1st-, 2nd-, and 3rd-trimester fetuses and full-term fetuses. CONCLUSIONS: There was an increase in the measurements for vermiform appendix, meso-appendix, and caecum with increasing gestational age; the localization of the vermiform appendix depended on the shape of the caecum, was different from that of adults and different between sexes, and there was also a significant difference in covering of the caecum with peritoneum between both sexes.

Appendix and cecum. Embryology, anatomy, and surgical applications.

Surgeons should be familiar with surgery of the cecum and appendix because the diseases of this region, especially appendicitis, are the most common indications for surgical exploration. Usually, diagnosis of appendicitis and appendectomy are not difficult, but atypical location of the appendix or other anatomic anomalies can make the diagnosis of appendicitis and appendectomy difficult. In cases of atypical anatomy or diffuse clinical picture, especially in young adults or elderly patients, the spectrum of embryologic and anatomic anomalies must be kept in mind to make the correct treatment decision for individual patients. If doubt persists, explorative laparotomy must be performed to avoid overlooking rare, acute, intra-abdominal abnormalities.

[Endocrine apparatus of the epithelium of the appendicular mucosa (the appendix-- an endocrine gland, functioning in the embryonal period?]. / Endokrinnyi apparat épiteliia slizistoi obolochki cherveobraznogo otrostka cheloveka (cherveobraznyi otrostok--éndokrinnaia zheleza, funktsioniruiushchaia v émbrional'nyi period?)

Based on the concept on gastroenteropancreatic system, endocrinocytes of which are diffusely scattered throughout the digestive tract epithelium and are found in pancreatic islets, an analysis of endocrine apparatus of epithelium in human appendicular mucosa was performed at different stages of ontogenesis. The response of appendicular endocrinocytes to clinical pathology of both this organ and the entire organism was studied. On the base of the analysis of the appendix function from morphological view, the authors proposed a hypothesis postulating it to be an organ equal to an actively functioning endocrine gland and its unique role on early stages of embryogenesis.

[The endocrinocyte differentiation of the mucosal epithelium of the human appendix]. / Differentsirovka éndokrinotsitov épiteliia slizistoi obolochka cherveobraznogo otrostka cheloveka.

By electron microscopy, the cambial elements of intestinal epithelium (band cells) are revealed to be sources of formation of the vermiform process epithelium endocrinocytes. By a successive differentiation the band cells are transformed into either secretory cells with monohormonal contents or "mixed" cells. The latter in their turn can be differentiated into mucous cells or lose their mucous component by transforming into endocrinocytes. In addition, mucous cells can be transformed into endocrinocytes by a direct differentiation.

[The ultrastructure of the epithelial endocrinocytes of the appendiceal mucosa in the human fetus]. / Ul'trastruktura éndokrinotsitov épiteliia slizistoi obolochki cherveobraznogo otrostka ploda cheloveka.

An electron microscope study of the epithelium of vermiform processes of 11-26 week old human fetuses showed seven types of endocrinocytes differing in ultrastructure and dimensions of secretory granules. In addition to the six known types of endocrinocytes (EC, D, D1, I, L and P), endocrinocytes of a 7th type were discovered which are beyond the International classification of endocrinocytes of the gastroenteropancreatic system. The overwhelming majority of endocrinocytes of the vermiform process epithelium form EC-cells. Besides, cells of a "mixed" type, both exo-endocrine and endo-endocrine cells, were revealed.

Assessment of gut intraepithelial lymphocytes during late gestation and the neonatal period.

Intraepithelial lymphocyte counts (IEL % enterocytes) were carried out in histological samples of jejunal, ileal and appendiceal mucosa of 39 neonates, aged from birth to 28 days. Correlations between IEL counts and developmental factors, namely gestational age, birth weight and intrauterine growth, as well as neonatal infections or feeding state were performed. No significant differences were observed among neonates grouped according to birth weight, intrauterine growth or neonatal infections. The pattern of feeding, however was associated with significantly higher IEL counts (p < 0.02) in the ileum in oral/enterally fed neonates than in the unfed or parenterally fed. Full-term neonates also had higher counts in the ileum (p < 0.02). In this group, oral/enterally fed neonates had the higher values. Thus, besides in utero development, the pattern of feeding might be considered as an important modulating factor on IEL postnatal expansion.

Blood vascular organization of the walls of vermiform appendix from human fetus. Examination of vascular corrosion casts in SEM.

Ten human vermiform appendices obtained from fetal corpses (160.0-240.0 mm of CRL) were examined using injection-micro corrosion method. Blood vascular bed reproduced with this method was observed with scanning electron microscope (SEM). Blood vascular bed structure of foetal appendix has been described, simultaneously with produced by them plexuses and organisation of microcirculation in a wall of the appendix. Collected results have been compared with data of other authors who conducted similar research on adult human appendices and appendices of several animal species.

Arterial vascularization of the vermiform appendix in human fetus.

In 50 human fetuses of the crown-rump length ranging from 88 mm to 185 mm (12 to 20 weeks), the variability of the arterial vascularization of the vermiform appendix was investigated using the injection method. 3 vascularization types were distinguished on the basis of the size and number of the supplying arteries. The obtained results were compared with those reported by other authors who studied vermiform appendix vascularization in adults. In most cases the vermiform appendix is supplied by single ramus arising from ileocolic artery.

[Endocrinocytes of the appendix in the human fetus]. / Endokrinotsity appendiksa ploda cheloveka.

At light and electron microscopic level endocrine cells of the human embryos (9-31-week-old) appendices have been studied. They appear in the human embryo appendix on the 11th week of development for the first time. Amount of the endocrine cells in the field of vision increases significantly on the 17th-24th and does not change on the 25th-31st weeks. Basing on certain morphological criteria, presence of EC-cells and those resembling S- or I-cells is demonstrated in the human embryo appendix. Thus, already during the embryonal period there are cells in the appendix, main function of which is to produce biogenic amines and peptide hormones, participating in local regulation of homeostasis.

Normal length of the human fetal gastrointestinal tract.

Little information is available on the normal length of the gastrointestinal tract in fetuses or on factors that may affect its growth. To determine normal growth patterns of the fetal intestine, 58 fetuses received in the Central Laboratory for Human Embryology between January 1, 1987, and July 1, 1988, in which no abnormalities were noted on autopsy, were studied. The gastrointestinal tract was removed from the fetus en bloc from the esophagogastric junction to the pelvic floor and dissected. Measurements of stomach, small and large intestines, and appendix length were made and correlated with gestational age as determined by footlength. Overall growth of the gastrointestinal tract as well as that of each component was linear with respect to gestational age. In addition, five fetuses with omphalocele, 16 with cardiac malformations, and 20 with chromosomal abnormalities were studied. The total lengths of the gastrointestinal tracts in the first group were below the normal range in four of five fetuses. Those with cardiac defects had intestinal lengths below the mean, but the measurements were abnormal in only three. In both groups those fetuses with chromosomal abnormalities appeared to have shorter intestinal tracts than those with normal or unknown karyotypes. The gastrointestinal tracts of aneuploid fetuses fell within the normal range until approximately 20 weeks gestation, after which growth decreased. This growth failure may reflect the growth retardation seen in fetuses with chromosomal abnormalities.

[Absence of the appendix. Apropos of a case]. / L'absence d'appendice. A propos d'un cas.

A case of congenital absence of the appendix is reported by the authors. It is a very rare anatomic finding, the frequency of which is about 1 p. 100 000. The awareness of this malformation must not authorize young surgeon to forsake a difficult search of the appendix. The diagnosis should not be made unless the entire right colon and the ileo-cecal area are mobilized and thoroughly explored.

[Embryonic structure of the cecal region in the chick embryo and its comparison with the human embryo]. / La structure embryonnaire de la région caecale chez l'embryon de poulet et ses résultats comparatifs avez l'embryon humain.

We have tried to expose some characteristics of the embryonic structure of the ceco-appendicular region in the chick embryo during its development. And so, to establish a relation between this region in the chick embryo and the same region in the human embryo.