| Head | Larger occiput in the infant naturally positions the head in the “sniffing” position Stabilize the head against lateral rotation Obligate nose breathers for the first few months |
| Mouth | Relative larger tongue volume in the mouth in the infant reduces the available space for instrumentation Edentulous |
| Neck | Larynx is more cephalad in the neck (C3–C4) in the infant Epiglottis is omega shaped and longer Vocal cords slant caudally at their insertion in the arytenoids Narrowest part of the upper airway is the cricoid ring (a solid, conically shaped, cartilaginous structure); pseudostratified columnar epithelium covers the ring Trachea is shorter (4–5 cm) |
| Tracheobronchial tree | Acute angle of the right mainstem bronchus at the carina Turbulent gas flow until the fifth bronchial division (resistance is related inversely to the radius to the fifth power) |