Cross-section of intestinal villi showing layers of mucous membrane and blood supply.

Girl in process of coughing forcing mucous buildup up through trachea and out the mouth and nose.

Illustration showing cricothyroid membrane identification by palpation; finger is inserted into opening made by initial incision for a surgical cricothyrotomy.

Trachea cross-section with lungs showing normal and asthmatic bronchiole.

Lateral view of child's head and neck showing scalpel in correct position to perform horizontal incision through cricothyroid membrane.

Illustration showing correct position of initial vertical incision (dashed line) for a surgical cricothyrotomy on a child; hand manually stabilizes trachea.

Illustration showing correct position of subcutaneous incision (dashed line) for a surgical cricothyrotomy on a child; skin has been retracted and sternohyoid m. exposed.

Illustrations showing initial, subcutanous and membranous incisions (dashed lines) for a surgical cricothyrotomy; (left) initial vertical incision; (middle) skin retraction, exposure of sternohyoid m.; (upper right) cricothyroid membrane palpation;

Hemostats maintain the horizontal opening in the cricothyroid membrane while tracheal tube is passed through the incision and into the trachea; sternohyoid m. is retracted; position of thyroid gland is indicated.

Larynx Cut-Away Side View Unlabeled

Wall of Colon Unlabeled

Trachea mucous membrane, SEM