The sequence of lanugo pattern development on the trunk wall in human fetuses.

BACKGROUND: Due to a growing interest in developmental disorders, and in the long-term skin appendage diseases, both in the cosmetic industry and among specialists in dermatology (broadly defined), there is an increasing number of papers on hair development. The publications by the present team of authors are part of this trend. OBJECTIVES: The aim of the study was to describe the topography and typology of skin pilosity patterns in human fetuses. MATERIAL AND METHODS: A total of 278 fetuses (141 male and 137 female) were qualified for the study. The gestational age ranged from 69 to 226 days after conception. All fetuses were taken from a local collection. RESULTS: The study revealed that the first single hairs occur on the posterior wall of the trunk in the 17th week of fetal life, and on the anterior wall between the 18th and 19th week. It was found that in human fetuses lanugo appears statistically significantly later on the skin of the anterior of the trunk than on its posterior. The difference in absolute time is almost 2 weeks of fetal life. No other differences were found in the development cycle of lanugo on the anterior and posterior walls of the trunk. A full pattern was first observed on the posterior wall of the trunk in a fetus in the 19th week, and on the anterior wall in the 21st week. It was found that the process of lanugo development was completed on the posterior wall in the 23rd week, and on the surface of the abdomen in the 26th week. CONCLUSIONS: The lanugo developmental cycle, consisting in the appearance of the first single hairs, then partial hair and subsequently the formation of final patterns, is the same on both walls of the trunk.

Metopic frontal suture in a patient with severe dentofacial deformity undergoing bimaxillary surgery.

Six cranial fontanelles are present in newborns along with cranial sutures. Cranial sutures are a synarthrosis type of joints that occur in the skull after closure of fontanelles. Because of ossification up to 24 months, all fontanelles should be closed. Normal frontal bone consists of only frontonasal, frontozygomatic, frontomaxillaris, frontolacrimalis, and main coronal sutures. Metopic frontal suture occurs very rarely in adults. Some metopic frontal sutures might be related to genetic or general disorders or perhaps are related to an improper ossification. In some cases, it persists as a complete suture extending from the nasion to the anterior angle of the bregma, and this condition is called metopism, or metopic suture. In this article, we present a patient with metopic frontal suture diagnosed accidentally during preparation for bimaxillary orthognathic surgery.

Observations on muscular attachments to human developing mandible.

BACKGROUND: The development of the mandible is closely related to Meckel's cartilage, mandibular division of trigeminal nerve and muscles of mastication. OBJECTIVES: The aim of the study was to investigate the muscular attachments to the developing mandible during prenatal life. MATERIAL AND METHODS: The observations were carried out on serial sections stained according to various histological methods. RESULTS: At stage 16, the rod shaped Meckel's cartilage followed the general curvature of mandibular process from the otic capsule to the future symphysis menti. The stylohyoid and styloglossus muscles were visible in close relation to the ventral end of Meckel's cartilage. On the medial surface of the cartilage, the mylohyoid muscle, as well as the genioglossus and geniohyoid muscles were visible. At stage 18 the muscles established their temporary attachments to Meckel's cartilage. At the same time, near the posterior end of Meckel's cartilage the primordia of articular disc and pterygoid muscle developed. The primordium of masseter muscle was observed in close relation to the angular portion of Meckel's cartilage at stages 19 and 20. Observations on the developing coronoid process showed the attachment of the lateral pterygoid muscle to Meckel's cartilage at stage 21. CONCLUSIONS: The muscles were connected to Meckel's cartilage by the end of 10th week of development, and after that they moved onto the developing mandible. The observations appear to confirm the hypothesis stating that the muscles attached to the Meckel's cartilage indeed influence the mandibular movements, resulting in a premature dislocation of the mandible.

The effect of an infant's environmental conditions and state of health on the teething of the primary incisors.

The objective of this research was to determine the relationship between the time when an infant's first incisor teething occurred, the infant's state of health and selected environmental and living conditions. 483 infants participated in this research and their health development was monitored monthly in a local hospital in Wroclaw. The teething of the infants was studied from the time of their birth until the age of 18 months. The descriptions of the infants' living and environmental conditions and their developmental stages were analysed on the basis of 10 standardised characteristics. The results of this study showed that there were strong relationships between the teething of infants' incisors, their living conditions and individual progress in health development.

The arching of the palate in twin foetuses.

The aim of the study is to examine the process of change with age of hard and total palate arching. Differences were compared in the arching of the hard and total palate in pairs of twins of the same sex and in pairs of twins of opposite sexes aged between 4 and 7 months of foetal life. On the basis of the results obtained it may be stated that: 1. There is some delay in the process of development of twin foetuses in comparison with ones from a single pregnancy; 2. There are no substantial differences between male and female twins and between twins from heterosexual pairs; 3. Much greater differences take place in older twins with regard to the features under examination.

The descriptive traits of the thymus of twin fetuses.

The aim of the study is to establish formulae for the descriptive traits of twins' thymus. The formulae, apart from the fundamental types, also include numerous descriptive traits of the right and left part of the thymus and specify the nature of the joints of the parts. Devising the formulae for the thymus helped to compare pairs of twins of the same and of different sex.