A morphometric study of normal and abnormal fetal to childhood tongue size

SmartLact8: A Bio-Inspired Robotic Breast Pump for Customized and Comfort Milk Expression

According to the 2018 National Immunization Survey conducted by the Center for Disease Control and Prevention (CDC), 83.9% of the breastfeeding mothers in the United States have used a breast pump at least once. However, the majority of existing products use a vacuum-only mechanism to extract milk. This causes common breast injuries such as nipple soreness, breast-tissue damage, and lactation complications after pumping. The objective of this work was to develop a bio-inspired breast pump prototype, named as SmartLac8, that can mimic infant suckling patterns. The input vacuum pressure pattern and compression forces are inspired from term infants' natural oral suckling dynamics captured in prior clinical experiments. Open-loop input-output data are used to perform system identification for two different pumping stages that facilitates controller design for closed-loop stability and control. A physical breast pump prototype with soft pneumatic actuators and custom piezoelectric sensors was successfully developed, calibrated, and tested in dry lab experiments. Compression and vacuum pressure dynamics were successfully coordinated to mimic the infant's feeding mechanism. Experimental data on sucking frequency and pressure on the breast phantom were consistent with clinical findings.

Bio-Inspired Breastfeeding Simulator (BIBS): A Tool for Studying the Infant Feeding Mechanism

OBJECTIVE

This work introduces a bio-inspired breastfeeding simulator (BIBS), an experimental apparatus that mimics infant oral behavior and milk extraction, with the application of studying the breastfeeding mechanism in vitro.

METHODS

The construction of the apparatus follows a clinical study by the authors that collects measurements of natural intra-oral vacuum, the pressure from infant's jaw, tongue and upper palate, as well as nipple deformation on the breast areola area. The infant feeding mechanism simulator consists of a self-programmed vacuum pump assembly simulating the infant's oral vacuum, two linear actuators mimicking the oral compressive forces, and a motor-driven gear representing the tongue motion. A flexible, transparent and tissue-like breast phantom with bifurcated milk duct structure is designed and developed to work as the lactating human breast model. Bifurcated ducts are connected with a four-outlet manifold under a reservoir filled with milk-mimicking liquid. Piezoelectric sensors and a CCD (charge-coupled device) camera are used to record and measure the in vitro dynamics of the apparatus.

RESULTS

All mechanisms are successfully coordinated to mimic the infant's feeding mechanism. Suckling frequency and pressure values on the breast phantom from the experimental apparatus are in good agreement with the clinical data. Also, the change in nipple deformation captured by BIBS matches with those from in vivo clinical ultrasound images.

SIGNIFICANCE

The fully-developed breastfeeding simulator provides a powerful tool for understanding the bio-mechanics of breastfeeding and formulates a foundation for future breastfeeding device development.

Morphometric development of the tongue in fetal cadavers

PURPOSE

The tongue is a specific organ for the sense of taste. It consists of the striated muscle and mucous membrane. Furthermore, it helps the functions of speech, chewing, and swallowing. In this study, we aimed to reveal some morphometric properties of the tongue in fetal cadavers.

METHODS

The study was conducted on a total of 45 fetal tongues (25 male tongues, 20 female tongues) aged between 17 and 40 weeks. The fetuses were divided into three groups as trimester II, trimester III, and full term. For each tongue, the length, width, area, free tongue length, and the terminal sulcus angle were measured using Image J program. The free tongue length/tongue length ratio was examined.

RESULTS

The obtained data were compared according to the trimester groups and genders. It was determined that the tongue length, width, area, and free tongue length increased during the trimesters and that there was no significant difference in the terminal sulcus angle and the free tongue length/tongue length ratio between the trimesters. No significant difference was found in all parameters between the genders.

CONCLUSIONS

This study presented significant data on morphometric development of the tongue. These data are thought to be useful for determining the anomaly and variations of the tongue.

Tongue development in stillborns autopsied at different gestational ages

OBJECTIVES

This study aimed to analyze, through the morphometric method, the perimeter and length of the tongue, the collagen fibers, and the perimeter of blood vessels at different gestational ages and fetal weights.

MATERIAL AND METHODS

Tongues (n=55) of stillborns autopsied at 23-40 weeks of gestational age were macroscopically analyzed, and their length and perimeter were measured. Fifty-five tongue fragments were collected through a longitudinal section in the region that accompanies the median lingual sulcus and histologically processed. Slides were stained with picrosirius and immunolabeled with CD31 antibody. Quantification was performed on collagen fibers under polarized light, and on the perimeter of vessels with the CD31.

RESULTS

A positive and significant correlation of gestational age with tongue perimeter and length was found. There was a positive and significant correlation between collagen fibers and gestational age, as well as between gestational age and the perimeter of blood vessels. Between collagen fibers and fetal weight, a positive and significant increase was observed. Regarding the correlation between the perimeter of blood vessels and the fetal weight, an increase was observed.

CONCLUSION

As gestational age advances, there is an increase in tongue perimeter and length, in the percentage of collagen fibers, and in vascular perimeter, demonstrating that tongue formation is directly related to tongue growth and development.

Short faces, big tongues: developmental origin of the human chin

During the course of human evolution, the retraction of the face underneath the braincase, and closer to the cervical column, has reduced the horizontal dimension of the vocal tract. By contrast, the relative size of the tongue has not been reduced, implying a rearrangement of the space at the back of the vocal tract to allow breathing and swallowing. This may have left a morphological signature such as a chin (mental prominence) that can potentially be interpreted in Homo. Long considered an autopomorphic trait of Homo sapiens, various extinct hominins show different forms of mental prominence. These features may be the evolutionary by-product of equivalent developmental constraints correlated with an enlarged tongue. In order to investigate developmental mechanisms related to this hypothesis, we compare modern 34 human infants against 8 chimpanzee fetuses, whom development of the mandibular symphysis passes through similar stages. The study sets out to test that the shared ontogenetic shape changes of the symphysis observed in both species are driven by the same factor – the space restriction at the back of the vocal tract and the associated arrangement of the tongue and hyoid bone. We apply geometric morphometric methods to extensive three-dimensional anatomical landmarks and semilandmarks configuration, capturing the geometry of the cervico-craniofacial complex including the hyoid bone, tongue muscle and the mandible. We demonstrate that in both species, the forward displacement of the mental region derives from the arrangement of the tongue and hyoid bone, in order to cope with the relative horizontal narrowing of the oral cavity. Because humans and chimpanzees share this pattern of developmental integration, the different forms of mental prominence seen in some extinct hominids likely originate from equivalent ontogenetic constraints. Variations in this process could account for similar morphologies.

Tongue thickness relates to nutritional status in the elderly

Many elderly people under long-term care suffer from malnutrition caused by dysphagia, frequently leading to sarcopenia. Our hypothesis is that sarcopenia may compromise oral function, resulting in dysphagia. The objectives of this study were to evaluate sarcopenia of the lingual muscles by measuring the tongue thickness, and elucidate its relationship with nutritional status. We examined 104 elderly subjects (mean age = 80.3 ± 7.9 years). Anthropometric data, such as triceps skinfold thickness and midarm muscle area (AMA), were obtained. The tongue thickness of the central part was determined using ultrasonography. Measurement was performed twice and the mean value was obtained. The relationship between tongue thickness and nutritional status was analyzed by Pearson’s correlation coefficient and Spearman’s rank correlation coefficient. AMA and age were identified by multiple-regression analysis as factors influencing tongue thickness. The results of this study suggest that malnutrition may induce sarcopenia not only in the skeletal muscles but also in the tongue.

Magnetic resonance imaging procedures to study the concurrent anatomic development of vocal tract structures: preliminary results

The vocal tract structures undergo drastic anatomic restructuring during the course of development from infancy to adulthood. This study demonstrates the feasibility of using MRI to examine the growth processes of the vocal tract. This method affords precise and detailed visualization of the soft tissues in the oro-pharyngeal region, while also providing images of related bony and cartilaginous structures. Information on anatomic restructuring contributes to the understanding of how speech emerges and develops, and it also establishes normative information that can be used in the assessment of developmental anomalies. This paper describes the method used to measure and examine the concurrent anatomic development of the various vocal tract structures during early childhood. Preliminary results from two pediatric subjects indicate that there is synchrony of growth in the different structures-both soft and hard tissues-, and that such synchronous growth appears to persist during periods of growth spurts.

Multivariate analysis of second trimester midfacial morphology in normal and cleft lip and palate human fetal specimens

To better understand the contribution of congenital dysmorphogenesis to postnatal midfacial dysplasia in individuals with complete cleft lip and palate (CLP), a series of studies were undertaken to investigate age related changes in a number of midfacial components for a sample of 20 normal and 9 complete CLP second trimester fetal specimens. Using data from this sample, the present study assessed the complex multivariate relationships among these variables which represent the fetal normal and CLP midface. Ten variables were standardized relative to crown-rump length and used in Canonical Discriminant Function Analysis (CDFA). CDF analysis revealed that five variables best described the midface and accounted for 72% of the overall variance. These included nasal capsule length, nasal airway volume, premaxillary length, premaxillary volume, and tongue volume. Classification using the CDFA coefficients resulted in correct group membership assignment for 26 of 29 total specimens (89.66%), 8 of 9 cleft (88.9%), and 18 of 20 normal specimens (90.0%). These results suggest that by as early as the second trimester CLP fetuses have a significantly distinct set of midfacial morphological relationships. Some or all of these factors may be responsible for postnatal growth dysplasias noted in CLP individuals.

Enlargement of the tongue in sudden infant death syndrome

Anatomic details of the infantile oropharynx and relationships to possible airway obstruction in sudden infant death syndrome (SIDS) are understood incompletely. Tonkin recognized this in 1975, suggesting that enlargement of the tongue might be important in SIDS, within the context of other anatomic and physiologic factors unique to early life. We therefore conducted a morphometric study of the tongue in 100 victims of SIDS and 36 control infants; the latter group consisted of infants with the same range in age and body size who had grown normally and died acutely. Highly significant differences in tongue weight, width, and thickness were demonstrated between the two groups by linear regression and analysis of covariance. Two multivariate techniques, stepwise discriminant analysis and factor analysis, identified marked discordance between somatic and lingual size in SIDS and a statistical uniqueness in tongue thickness. Certain explanations for lingual enlargement in SIDS were ruled out: redistribution of fluid and other effects of death, postmortem interval, duration and mode of feeding, and smallness of control tongues. At present, the functional significance of these observations is unclear. The effects of both normal and increased tongue size on airway patency are, however, widely recognized. Further studies of the enlarged tongue, addressing such topics as in situ anatomy and developmental mechanisms, are necessary to establish the potential for pathophysiologic consequences in SIDS.

Developmental correlates of midfacial components in a normal and cleft lip and palate human fetal sample

Midfacial hypoplasia in patients with complete clefts of the lip and palate is considered to be the result of congenital dysmorphogenesis combined with surgical effects. The present study describes congenital correlates of midfacial hypoplasia by examining the relationships between premaxillary size and a number of adjacent oronasal capsular components in a sample of second trimester normal and complete cleft fetal specimens. Midfacial relationships from previously published data from 3-D computer reconstructions of histologic material were assessed by multiple regression and path analyses. Stepwise multiple regression analysis revealed that the combination of age (body size) and nasal septal length were the best predictor variables of premaxillary length and accounted for 90 percent and 93 percent (p less than .01) of the variance in normal and cleft fetal specimens, respectively. Tongue length was seen to slightly increase the R2 values in the cleft, but not the normal sample. Path analysis results revealed that with body size held constant, nasal capsule volume explained only 3 percent of premaxillary variance, while septal length accounted for approximately 45 percent of the variance (p less than .05). Results show that the relationships of the midfacial components in the cleft fetal sample closely followed normal second-trimester midfacial growth patterns and suggest that the septal-traction model may be a more parsimonious and primary explanatory mechanism of early midfacial growth than the functional matrix model in both normal and complete cleft fetal specimens.

An anatomic comparison of cebocephaly and ethmocephaly

Cebocephaly (hypotelorism, single-nostril nose) and ethmocephaly (hypotelorism, interorbital proboscis) lie in the middle of the spectrum of craniofacial changes associated with holoprosencephaly. Because these defects and thorough anatomic studies of them are rare, knowledge concerning morphologic as well as pathogenetic relationships is lacking. We report the autopsy findings and anatomic features of the dried skull of a 31 week fetus with cebocephaly and the craniofacial dissection of a 36 week fetus with ethmocephaly. Both manifested dysplastic changes of the ethmoid bone and anterior portion of the sphenoid bone, with concomitant hypotelorism and defects of the medial orbital walls. Through these latter defects, the eyes were joined in the ethmocephalic fetus (synophthalmia). Other changes of bone (single optic foramen, approximated maxillae, choanal atresia, thickened palate) and soft tissue (eccentric or fused extraocular muscles, single optic nerve) in both fetuses resembled those reported in other cases of cebocephaly and ethmocephaly, as well as cyclopia. In the 19th century, both cebocephaly and ethmocephaly were classified as two-orbit variants of cyclopia, a view supported by the present study.

Whole embryo morphometry in teratogen screening

Current methodology in embryo evaluation involves qualitative assessment of razor blade and paraffin serial sections. Presently, no one has applied existing computerized morphometric techniques to examine embryos. A technique has been developed that enables investigators to section embryos at 150 mu, thereby greatly reducing the number of sections and making morphometric analysis possible. This type of analysis permits the precise volumetric determination of several developing organ systems. The aim of this study was to evaluate the feasibility and sensitivity of whole embryo morphometry in teratogen screening. Cadmium chloride, a well-established teratogen, was chosen because of its ability to induce exencephaly in approximately one-half of offspring while having no observable effects on the remaining exposed embryos. It was found that both exencephalic and normal-appearing cadmium-exposed embryos had significantly smaller total cellular, neuroepithelial, otic vesicle, optic assembly, limb bud, and cardiac mesenchyme volumes when compared to controls. Also, the neuroepithelial volume of the exencephalic embryos was significantly smaller than the normal-appearing cadmium-exposed embryos. These results suggest that in addition to inducing exencephaly, cadmium chloride has an overall inhibitory effect on embryonic growth. We have shown that whole embryo morphometry is a sensitive means of evaluating embryonic growth that permitted determination of cadmium-induced aberrations not discernable by currently employed techniques. In light of these results, we feel this technique shows promise for future investigations of known and suspected teratogens.

Prenatal growth of the median face

The growth and development of the median facial region remain incompletely understood. Data concerning the prenatal size and growth rates of facial components are especially lacking. A group of fetuses and newborn infants with apparently normal craniofacial development and body size was therefore studied at autopsy. The interorbital distance and dimensions of the external nose, philtrum (upper lip), and mouth were determined; the growth of morphogenetically related structures--the ethmoid bone and tongue--was also studied. The slopes of linear regressions of these variables against body length indicated that growth of the median facial region proceeds slowly in the latter half of gestation. The center of the face seems to grow slower than the sides of the face. A multivariate technique, factor analysis, identified and ordered relationships among the variables. The best statistical summary of size in the median face was given by four transversely oriented variables, nose breadth, outer orbital distance, inner canthal distance, and mouth width. Within the region, a secondary cluster was dominated by sagittally oriented variables. The second best summary of median facial relationships was provided by three variables of lingual size and was followed by a group of variables representing ethmoidal size. This pattern of growth may represent the effects of a developmental hierarchy. Growth seems to be coordinated along the major axes of the body, with transverse growth controlled more rigidly than sagittal growth. The statistical independence of the three regions suggests that the controls of growth are also separate.