ABSTRACT
106 ethmoidal specimens ranging from 12 to 40 weeks of embryonic age were cut into serial sections and observed by histological method. The results showed that the ethmoid sinus began its development at about 21-23 weeks of fetal life. The frontal folds or furrows were formed by extensions or evaginations of the nasal mucous membrane from the superior and lateral wall of the middle and superior nasal meatuses. The ethmoid cells appeared at 24-26 weeks and they kept their own small ostia that opened into the middle and superior nasal meatuses. The number and size of the ethmoid cells were increased with the age. The cell cavities showed balanced enlargement. At birth each ethmoid labyrinth had 6-11 cells, measuring on the average 1.7?1.3?2.0 mm~3 in size. The distribution of the ethmoid cells approached those of mature age. The epithelium of the ethmoid sinus was cuboidal or low columnar in shape. Cilia appeared sparse. Tunica propria, mainly composed of the connective tissue and its stroma, was thick, loose, and less vascular and glandular. It suggested that the ethmoid sinus was one of the accessory nasal sinuse that developed first. The ethmoid sinus presented at birth and its appreance were not synchronous, but their location were relatively invariable. The histological structure of the mucous membrane in the ethmoid sinus was somewhat different from those of the nasal mucous membrane. It showed that the development of the ethmoid mucous membrane was still imperfect in the newborn.
ABSTRACT
The morphology,location,capsules and ligaments of 100 cases of thyroid glands have been carefully observed.The variation of the accessory thyroid glands and the levators of thyroid glands are described in detail.Among the 250 cases studied,the morphological types of thyroid glands of the Chinese are as follows: a.Basic pattern,two lateral lobes connected with isthmus(37.6%). b.Same as type “a”,but with one extra pyramidal process(55.6%). c.With no isthmus(2.8%). d.With no isthmus,but there is a pyramidal process on both lateral lobes(2.8%). e.A new pattern is found which has not yet been mentioned in textbooks:-3 cases with two lateral lobes connected with isthmus,but eath lobe having an extra pyramidal process(1.2%).
ABSTRACT
In 100 cases studied,all specimens show the presence of a superior thyroid artery,and 99% of them are with comitans vein.Nineteen percent of the specimens are found with no inferior thyroid artery on one side.The frequency of the appearance thyroidea ima is about 10%.Fifty eight percent of the specimens show a middle thyroid veins wich is directly joining the anterior wall of the internal jugular vein.Fifty five per- cent of the inferior thyroid vein are double-trunked.Detail data of the arising point and passage of the main vessels of the thyroid gland have been collected to serve as a guide for surgical operation.
ABSTRACT
In this study, 90 fetuses aged from 3～10 months were collected, 48 of 90 ductus arteriosi were studied with histological method in order to observe the changes in the different fetal stages and to approach its closing mechanism. The gross morphology of the 90 ductus arteriosi and their abjacent portions were also observed. Ductus arteriosus belong to the muscular type artery. It was found that the histological structure of the ductus arteriosus after the 7th month was particulary different from that before the 7th month, the beginning of the perinatal period is the critical period of the histological changes of the ductus arteriosus, since the beginning of the perinatal period, the duct had grown rapidly, the internal elastic membrane was fragmented or split, the smooth muscular fibers of the inner layer in the tunica media remarkbly thickened and was disarranged, some oblique and spokelike smooth muscular fibers protruded into the intima through the gaps between the fragmental internal elastic membranes and formed typical intima cushions with the thickened tunica intima. From the beginning of the perinatal period, the lungs and the vessels of pulmonary circulation had been well developed, but the right and left pulmonary arteries were in the state of "the door being placed but usually closed". Blood of the pulmonary trunk flowed into the much smaller ductus arteriosus, hence the ductus arteriosus was an artery affected by local hyper-pressure, its histological changes were similar to the degeneration of the muscular artery affected by hypertension disease, but it had no lipid deposit. This local hyper-pressure may be the intrinstc cause of the histological changes of the ductus arteriosus. These histological changes were the morphological foundation of the functional closure and anatomical closure of the ductus arteriosus after birth.
ABSTRACT
The normal round window membrane in human fetus was examined by transmission electron microscopy. The membranes in 5 to 9 months old fetus consist of the following three layers: (1) an outer squamous epithelial layer facing the middle ear, there was no epithelium in 4-month-old stage, (2) a middle fibrous layer consists of collagenous and elastic fibrils, fibroblasts, fibrocytes, blood vessels, and nerves, (3) an inner layer of simple flat cell(mesothelial cell) facing the scala tympani. With the advance of age the epithelium is getting thinner, the number of fibroblasts is reduced but that of fibrocytes is increased, collagenous and elastic fibrils grow gradually in density.The round window membrane in 8-month-old fetus is simillar to the ultrastrucrural characteristics of that in adult. The round window membrane has an important and complicated physiological function. The epithelium of the tympanic layer with tight junction and many desmosomes appear to present a barrier to free diffusion through the intact membrane. The stability and elasticity of the membrane provide protection against rupture and elasticity plays a role in the physiology of hearing as well.
ABSTRACT
The external laryngeal nerve is present in all 100 cases studied. It lies closely to the posterior of the superior thyroid vessels, and they are wrapped in a common neurovascular sheath. When operating the superior polar of the lateral lobe, it is necessary to seperate the vessels from the nerve, and then tie the superior thyroid vessels selectively on the upper polar of the lateral lobe in order to avoid injury of the external laryngeal nerve.Statistical studies of different types of the topographic relation between the recurrent laryngeal nerve and the inferior thyroid artery have been made. A topographic anatomy of the recurrent laryngeal nerve is discussed in detail, and suggestions on avoiding its injury during surgical operations have also been made on anatomical bases.It is observed that abnormal passage of the right recurrent laryngeal nerve caused, by the retro-esophageal right subclavian artery is 1%.
ABSTRACT
The knowledge of the location of the parathyroid glands is valuable in the parathyroidectomy and subtotal thyroidectomy. 319 parathyroid glands have been found in 100 cases. 80% of the parathyroid glands are situated in tile normal yet concealed position: the upper pair, above the mid of the posterior margin of the lateral lobe of the thyroid gland, while the lower pair, near the inferior 1/3 of the posterior margin of the lateral lobe. They all lie in the space between the proper capsula and fascia sheath of the thyroid gland.In subtotal thyroidectomy, the posterior part of the lateral lobe is usually preserved, it aims to protect the parathyroid gland, and is an effective procedure to prevent the injury of the recurrent nerve. Morever, it is most important to preserve the fat and loose connective tissue near the lateral lobe of the proper capsule, in order to avoid the excission of the parathyroid glands on abnormal locations (16%). In procedure of the operation on parathyroidoma or hyperparathyroidism, the first thing is to examine the condition of the lower pair parathyroid glands, which usually lie near or below the lower end of the lateral lobe and on the both sides of trachea. If the lower pair of parathyroid glands is identified to be pathological in nature, then the examination of the other pair can be performed on routine. 4% of the lower pair of the parathyroid glands are found on the both sides of trachea.A clear standard statistical diagram of the location of the parathyroid gland has been designed in this study.