Thoracic Development Flashcards
Pleural cavities
space in which lungs develop and persist
Pericardial cavity
space in which heart develops and persists
Peritoneal cavity
space in which abdominal viscera develops and persists
Septum Transversum
will become the central tendon of the thoracic diaphragm
Intraembryonic Coelom
primordium of embryonic body cavities - develops during 4th week
Horseshoe shaped cavity develops in the lateral mesoderm
Cranial end
future pericardial cavity
embryo undergoes head-fold, bringing pericardium and heart venterocaudally
Caudal limbs
future pleural and peritoneal cavities
fold in horizontal plane bringing two caudal limbs together - fuse to form peritoneal cavity (lateral folds)
Ectopia cordis
cranial fold needs to be finished before lateral folds or heart will be outside the body wall
Sternum never develops
Mesenteries
gut tube
double layer of peritoneum that extends from abdominal wall, divides peritoneal cavity into right and left halves
Dorsal Mesentery
Permanent Structure
Provides route for vasculature, nerves, and lymphatics to developing organs
Ventral Mesentery
remains attached to caudal part of foregut (suspends primordial liver, stomach, and proximal part of duodenum) - becomes falciform ligament and lesser omentum and visceral peritoneum surrounding liver
Parietal peritoneum
covers body wall
Visceral peritoneum
covers organ
Pericardioperitoneal canals
term for intraembryonic coelom after folding of embryo
lies lateral to foregut
dorsal to septum transersum
partitions form in each canal due to developing bronchial buds
Pleuropericardial folds (cranial ridges)
Located superior to developing lungs
Separate pleural from pericardial cavities - divides lung from pericardial space
Phrenic nerve gets caught in these folds
Pleuroperitoneal folds (caudal ridges)
Located inferior to developing lungs
Separate pleural from peritoneal cavities
become part of diaphragm
Doesn’t fuse in center - right closes first, then left
Pleuropericardial membranes
enlargement of pleuropericardial folds becomes partition that separates pleural from periardial cavities
contains common cardinal veins and phrenic nerves
common cardinal veins
drain primordial venous system into sinus venosus of primordial heart
Pleuropericardial membrane becomes the
fibrous pericardium, comes from body wall (somatic mesoderm) - inner layer
primordial mediastinum
forms after 7th week, after pleuropericardial membranes have fused with the ventral mesenchyme
contains all organs of thoracic cavity except lung and the pleura
Pleuroperitoneal membranes
enlargement of pleuroperitoneal folds becomes partition that separates pleural from peritoneal cavities
forms posterior portion of diaphragm
During 6th week, these membranes extend ventromedially and fuse with dorsal mesentery of esophagus and septum transversum
Diaphragm develops from
septum transversum
pleuroperitoneal membranes
dorsal mesentery of esophagus
muscular ingrowth from lateral body walls
what vessels are caught in lateral body wall folds
esophagus, aorta, IVC - run through developed diaphragm
Diaphragm is innervated by
phrenic nerve - C 3,4,5
Closure of pleuroperitoneal cavities are assisted by
migration of myoblasts into pleuroperitoneal membrane - also aids in innervation (myoblasts migrate from 3-5 cervical myotomes and carry their nerves with them)
Posterolateral defect
intestines in lung space - looks like gas/space on radiogram
left side that closes 2nd never fuses
intestines crush lungs
Congenital hiatal hernia
protrusion of upper part of stomach into thorax through tear or weakness in diaphragm
