The face of an infant and child is not merely a scaled-down version of that of the adult. Newborns have a small face relative to cranial size. The newborn face also appears round and relatively flat with large, wide-set eyes. Throughout childhood, the face elongates because of maxillary and mandibular growth. As facial height increases, the ratio of face to the cranium changes from 1:3 for infants to 1:2 for adults. Concurrent growth of the skull base causes increased facial projection. The chin and cheek bones become more prominent, and the pyriform aperture of the nose is displaced inferiorly relative to the orbits.

Sinonasal growth is closely related to maxillary and facial growth. The vertical height of the nose increases substantially during adolescence. Among young children most of the height is cartilaginous, explaining the low incidence of nasal fractures in this age group. Growth of the external nose is completed at about 15 years of age for girls and 18 years for boys and is believed to come from osseous and cartilaginous centers in the nasal septum. Elective nasal operations consequently are deferred until adolescence.

The maxillary, ethmoid, and sphenoid sinuses are present at birth but are small. The maxillary sinus is about the size of the middle ear space at birth, begins rapid growth at 3 years of age, and attains full adult size by 15 years of age. The sphenoid sinus remains small until 4 years of age, when growth begins to accelerate; adult dimensions are reached by 15 years of age. The ethmoid sinuses are present at birth and are the most frequent site of acute and chronic sinusitis among young children. Considerable ethmoid pneumatization occurs between 3 and 7 years of age, and adult proportions are achieved by 12 to 14 years of age. The frontal sinus is generally not present at birth, but growth begins by 3 years of age. By 8 years of age the frontal size becomes visible on sinus radiographs.

Development of the ear has several clinical implications, including the predisposition of children to eustachian tube dysfunction, and the surgical staging of reconstructive procedures. The immature pinna (external ear) has adult morphologic features at birth but it is soft and pliable. Operations to correct
excessive protrusion (otoplasty) can be performed safely by 4 to 5 years of age, when most of the pinna growth has occurred. Adult size is attained by 9 years of age.

The tympanic membrane has its full dimensions at birth, but is thick and lies in a nearly horizontal position. With ossification of the ear canal by 2 years of age, the tympanic membrane assumes its vertical orientation. The ossicles (malleus, incus, and stapes) are of adult size and configuration at birth. Although pneumatization of the middle ear is nearly complete at birth, pneumatization of the mastoid air cells continues throughout early childhood, mostly in a lateral and posterior direction. In early childhood, the mastoid cortex is very thin, which accounts for the subperiosteal postauricular spread of mastoid infection. The thin cortex also accounts for the superficial position of the extratemporal portion of the facial nerve at birth, making it relatively unprotected and vulnerable to traumatic injury.

The eustachian tube is only half its adult length at birth and is nearly horizontal (infant 10 degrees, adult 45 degrees). This short length, coupled with the less acute angle of orientation and nasopharyngeal carriage of viruses and bacteria, makes the normally sterile middle ear space more susceptible to contamination from the nasopharynx. Along with the relative immaturity of the pediatric immune system, these characteristics result in children being highly susceptible to acute and chronic infections of the middle ear (otitis media). With growth, the eustachian tube angles inferiorly and opens into the nasopharynx at the level of the inferior turbinate. By the age of 7 years the eustachian tube assumes its adult size and configuration, and the incidence of otitis media is greatly reduced.

Newborns have a small oral cavity because the mandible is foreshortened, producing relative macroglossia. These anatomic considerations contribute to the newborn’s status as an obligate nasal breather until 6 to 12 weeks of age. The larynx is fully formed at birth but is located higher in the neck, at the level of the fourth cervical vertebrae (C4). The angle between the glottis and the more floppy omega-shaped epiglottis is more acute than in later life. This allows overlap of the epiglottis with the soft palate, which establishes the nasopharyngeal airway used during sucking. Additionally the submucosal tissue is loose and the subglottis is small making the pediatric airway particularly intolerant of swelling from any inflammation or trauma, as may occur with intubation or foreign body aspiration. With growth of the neck, the larynx gradually reaches its adult position at C5 to C7 at the time of puberty.