Week Of Embryonic Life Research Articles

Unusual nasal tumors; report of 2 cases.

IT IS THE purpose of this report to present two rare tumors of the nasal cavity, with a review of the literature. Case 1 concerns a cystic basal cell carcinoma of the middle turbinate body. Case 2 concerns an adenocarcinoma arising from the same site. During the process of this review, there was found to be a great lack of uniformity in terminology. Thus, the same type of tumor is called cylindroma, adenoma, endothelioma, mixed salivary gland tumor, cystic basal cell carcinoma, adenosarcoma or adenocarcinoma, by both foreign and domestic writers. An attempt at clarifying these terms is made. EMBRYOLOGY OF THE NASAL CAVITY The lining mucosa of the nasal cavity and paranasal sinuses is formed from the invaginating ectoderm of the olfactory plates at the end of the fourth week of embryonic life. It is continuous posteriorly with the mucosa of the nasopharynx, which is entodermal in origin but

ETIOLOGY OF CONGENITAL DISLOCATION OF THE HIP

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MECKEL'S DIVERTICULUM

MECKEL'S diverticulum is the commonest developmental anomaly of the intestinal tract. My experience with this condition is based on 8 cases in which the condition was diagnosed or verified at operation in my private practice and 2 cases observed while I was a graduate student. Before discussing the more interesting cases in some detail it would be fitting to review the surgical pathology of this anomaly. The diverticulum is a persistent remnant of the vitelline duct or yolk stalk. 1 In early embyronic life it passed from the yolk sac along the umbilical cord to that portion of the midgut which later becomes the ileum. In normal circumstances the vitelline duct is obliterated at the end of the sixth or seventh week of embryonic life, but it may persist to a greater or lesser extent and be responsible for many symptoms and complications both in infantile and in adult life.

MALIGNANT TUMORS OF MECKEL'S DIVERTICULUM

A malignant tumor of Meckel's diverticulum is rare enough to be considered a pathologic curiosity. The literature on other lesions associated with Meckel's diverticulum, however, is increasing each year. We have therefore thought it opportune to combine the report of a case of a malignant tumor of Meckel's diverticulum with a general survey of the literature. Meckel's diverticulum is a developmental anomaly of the intestinal tract which is found in about 2 per cent of all adults. The mechanism responsible for the production of this anomaly, as is well known, is failure of the omphalomesenteric duct and its accompanying vessels to become completely obliterated. Normally this obliteration takes place in the third to the fifth week of embryonic life. The yolk stalk may fail to become completely obliterated, leading in rare cases to an intestinal fistula opening through the umbilicus; occasionally the duct becomes obliterated, except at its distal part.

Tumors of the Nasal and Paranasal Cavities

Embryology and Classification: The lining membrane of the nasal cavity and sinuses is formed from the invaginating ectoderm of the olfactory plates at the end of the fourth week of embryonic life. It is continuous with the mucous membrane of the nasopharynx, which is entodermal in origin but of similar histologic structure. At first these olfactory plates are in contact with the cerebral vessels, but later the meninges and ethmoid bone separate them from the brain. Outgrowths of the nasal lining in the third month form the middle meatus, and further extensions at the posterior end form the pockets for the maxillary sinus. From the anterior portion four furrows develop, two representing buds for the frontal sinuses and the remainder the air cells of the ethmoid. The lining membrane differentiates to form ciliated columnar epithelium resembling the respiratory epithelium of the pulmonary tract. From the undifferentiated cells of the basal layers the mucous glands of Bowman are derived. The submucous tissue of this region is particularly rich in mucous glands and in blood vessels. Portions of the olfactory ectoderm in the upper ethmoidal region are neuro-epithelial in character and form connections with the olfactory bulb. Gangliomas may rarely form from these cells.

The Mesentery

CONSIDERED anatomically, the mesentery represents two layers of peritoneal lining separated by loose connective tissue in which branches of arteries, veins, and lymphatics extend to the intestinal tract. Therefore, broadly speaking, we should include the following structures: liggamenta, gastro-hepaticum, hepatoduodenale, gastro-lienale, gastro-colicum, bursa omentalis, mesocolon transversum, and sigmoideum, besides the radix mesenterii, which is the chief object of our discussion. In a restricted sense, the mesentery is, then, that part of the duplicated peritoneal lining which extends from the radix mesenterii to the small intestine. It originates on the left border of the second lumbar vertebra and extends obliquely toward the right iliac fossa, ending just above the right sacro-iliac region. All of these structures show numerous anatomic variations, some of which are of clinical importance. To understand this, it is advisable to review briefly their embryologic development. Maldevelopments and Variations.—In the fifth week of embryonic life, the digestive tract is represented by a long duct: the fore-gut is fixed in the mid-line of the body by the ventral and dorsal mesenteries (Hubeny). The mid- and hind-guts are suspended from the posterior body wall only by their dorsal mesenteries: the ventral mesenteries have disappeared. The mesentery of the mid-gut is long, and the intestinal tube forms a long U-loop which is supplied by the superior mesenteric artery. The U-loop cannot move freely in a lateral direction, because its apex is fixed to the umbilicus by means of the vitelline duct. However, it is able to rotate around its base, where the two limbs of the U are close together. After the fifth week the mid-gut increases in length very rapidly: its mesentery becomes fan-shaped and capacious, except at the base of the loop, where it is reduced to a narrow isthmus through which the superior mesenteric artery passes. At the beginning of the third month the U-shaped loop twists around the isthmus from right to left, thus elevating the distal part of the hind-gut, which becomes attached on the left side, as the splenic flexure of the colon. The rest of the colon proximal to this swings over the front of the abdominal cavity from left to right, becoming attached to the structures of the posterior body wall along a line extending from the left to the right kidney, and thence down to the right iliac fossa. This explains why a part of the small gut (second and third parts of the duodenum) is situated behind the transverse colon, while the rest (jejunum and ileum) lies freely in the abdomen, below the transverse colon. It is attached with its radix mesenterii posteriorly along the line described above, extending obliquely from the second lumbar vertebra on the left side to the right sacro-iliac region. The free mesentery is covered on both sides by the peritoneal lining; the attached one, on its anterior surface only.

THE ADRENALIN CONTENT OF THE SUPRARENAL CAPSULE IN THE CHICK EMBRYO

The time of appearance of adrenalin in the suprarenals has often been investigated. Fenger (1912) and McCord (1915) found adrenalin in the sixth week of embryonic life in cows, sheep and pigs. Miller (1926) found adrenalin and the chromic reaction in mice on the 14th and 15th days. Hogben and Crew (1923), using the intestinal assay method, came to the conclusion that adrenalin undoubtedly appears in chicks after the 16th day of embryonic development, but not before the 14th day. Lutz and Case (1925) also studied the chick embryo, using the frog's eye assay method. The presence of adrenalin was always demonstrated after the tenth day; in some, but not all cases it was found as early as the eighth day. As to human embryos, it was observed by Moore and Purinton (1900) and by Thomas (1926) that both adrenalin tests and the chromic reaction failed towards the end of embryonic development. The present research with chick embryos was undertaken to determine the time when adrenalin appears, the relation between a...

UTERUS BILOCULARIS.Read in the Section of Obstetrics and Diseases of Women, at the Forty-first Annual Meeting of the American Medical Association, at Nashville, Tenn., May, 1890.

Of the various forms of malformation of the uterus due to defective development of the ducts of Muller, uterus bilocularis shows the least deviation from the normal, and ranks as second in point of frequency of occurrence. Of the 271 cases of such malformations, the histories of which have been studied by the writer, there were of uterus bipartitus, 14; uterus unicornis, 18; uterus bicornis, 175; uterus bilocularis, 68. This represents all the cases on record and classified in the library of the Surgeon-General's Office to May 1, 1888. The causes operating to produce these malformations are unknown. The inner walls of the ducts of Muller meet and coalesce previous to the eighth week of embryonic life. The septum disappears between the eighth and twelfth weeks. It is in these periods that the form of malformation is, in the main, determined. When the walls of the ducts fuse, but do