Chapter 2. Developmental Physiology and Pharmacology

: Developmental Changes of the Rib Cage from Birth to Adulthood – Adults can increase lung volume by raising the ribs and contracting the diaphragm. Early in development, the configuration of the rib cage and muscular attachments of the diaphragm place the newborn at a mechanical disadvantage because the ribs are already “raised,” and contraction of the diaphragm results in a relatively small increase in thoracic cavity volume. Illustration by Rob Fedirko.

: Normal Newborn Echocardiograph – The normal newborn electrocardiograph demonstrates a preponderance of right-sided forces as evidenced by a QRS axis greater than 90 degrees, and decreasing R wave size from right to left in the precordial leads. T waves are normally inverted in lead AVR and the right-sided precordial leads. ECG courtesy of Dr. Akash Patel.