Development of the Diaphragm : Human Embryology скачать в хорошем качестве

Development of the Diaphragm : Human Embryology

📌𝐅𝐨𝐥𝐥𝐨𝐰 𝐨𝐧 𝐈𝐧𝐬𝐭𝐚𝐠𝐫𝐚𝐦:-   / drgbhanuprakash   📌𝗝𝗼𝗶𝗻 𝗢𝘂𝗿 𝗧𝗲𝗹𝗲𝗴𝗿𝗮𝗺 𝗖𝗵𝗮𝗻𝗻𝗲𝗹 𝗛𝗲𝗿𝗲:- https://t.me/bhanuprakashdr 📌𝗦𝘂𝗯𝘀𝗰𝗿𝗶𝗯𝗲 𝗧𝗼 𝗠𝘆 𝗠𝗮𝗶𝗹𝗶𝗻𝗴 𝗟𝗶𝘀𝘁:- https://linktr.ee/DrGBhanuprakash Development of the Diaphragm : Human Embryology The diaphragm originates from an unpaired ventral portion (septum transversum), from paired dorsal lateral portions (pleuroperitoneal folds), and from an irregular medial dorsal portion (dorsal mesentery). The septum transversum, formed during the third week of gestation, separates the pericardial region from the rest of the body cavity. This part of the diaphragm grows dorsad from the ventral body wall and moves caudad with the other contributors to the diaphragm to reach the normal position of the diaphragm at about 8 weeks. The pleuroperitoneal folds arise on the lateral body walls, at the level where the cardinal veins swing around to enter the sinus venosus of the heart. These folds extend medially and somewhat caudad to join with the septum transversum and the dorsal mesentery to complete the development of the diaphragm at about the seventh week; the right pleuroperitoneal canal closes somewhat earlier than the left. Muscle fibers migrate from the third, fourth, and fifth cervical myotomes, carrying along their innervation, and grow between the two membranes to complete the structures of the diaphragm. During the 10th week, the intestines return from the yolk sac to the abdominal cavity and, at about 12 weeks, rotation and fixation of the intestines occur. A delay or variation in the described timetable may result in a variety of congenital hernias with or without a hernial sac or may even result in a congenital eventration of a hemidiaphragm. Early return of the intestines to the abdomen before closure of the pleuroperitoneal membrane results in a hernia through this opening (a so-called foramen of Bochdalek hernia). A sac is not usually present, but if it is, the return of the intestines may have occurred after the closure of the pleuroperitoneal membrane but before the migration of the cervical myotomes between the membranes. Foramen of Morgagni hernias occur anteriorly, almost always have a sac, and therefore probably result from lack of ingrowth of the cervical myotomes. A congenital short esophagus is related to late closure of the diaphragm and early return of the intestine to the abdomen. Congenital eventration may be a total error of ingrowth of cervical myotomes in one or both hemidiaphragms and therefore is actually a large congenital diaphragmatic hernia and not an eventration. An absent diaphragm probably represents an error of growth of the septum transversum and other embryologic elements. Duplication of a hemidiaphragm can occur. The fusion and formation timetable variations may also involve defects in the diaphragm in association with certain vascular anomalies of the lungs and heart. #diaphramdevelopment #DevelopmentofTheDiaphragm #developmentofdiaphragm #diaphragmembryology #embryology #humanembryology #usmle #mbbs #anatomy #neetpg #usmlestep1 #nationalexitexam #nationalexittest