Essentials of Diagnosis
- History of recent trauma to midface; should assess mechanism of injury, presence of epistaxis or rhinorrhea, history of previous injury, and new onset of nasal airway obstruction or deformity.
- On examination, note any mucosal laceration, septal disruption, or septal hematoma.
- Depending on severity of insult, must rule out concurrent injury to eyes, lacrimal system, paranasal sinuses, teeth, and oral cavity.
General Considerations
Nasal fracture as a result of trauma to the midface is considered the most common of head and neck fractures. Frequently the result of physical altercation, nasal trauma is most often not life-threatening; however, significant functional and aesthetic impairment may result if these injuries are not accurately diagnosed and addressed in a timely fashion.
The incidence of nasal fracture is high in both adults and children. Of maxillofacial injuries, fractures of the nasal bones account for up to 39–45% of cases reported in adults, and up to 45% of injuries in children. In adults, the highest rates of incidence are found among men, with a 2:1 predominance over cases reported in women. In men, nasal fracture is most often associated with intentional trauma and is clearly more common in the 15- to 25-year age group. In women, nasal trauma is usually the result of personal accidental injury; most commonly the result of falls and is often seen in patients over the age of 60.
In children, a clear gender predilection for injury is less likely, although cases are more often reported in boys. Also, more cases of nasal trauma in children are the result of accidental injury related to sports and play rather than physical confrontation. It is important to note, however, that anywhere from 30% to 50% of all pediatric victims of abuse present with maxillofacial injury, a concern not to be overlooked, particularly when evaluating the possibility of fracture concealed by the presence of facial edema.
Pathogenesis
Given the central and prominent position of the nasal bones and the significant lack of skeletal support for their position, the nose is particularly vulnerable to fracture as a result of maxillofacial injury. Reports indicate that the amount of force required to create a fracture of the nasal structure is small, possibly as little as 25 pounds of pressure. Superiorly, the structure of the nasal bones thickens with support from the underlying nasal spine of the frontal bone, an area more resistant to injury than the distal, thinning segment of the nose, which is unsupported and much more often the location of a fracture.
Trauma to the nasal cartilage, either from a directed frontal or inferior assault or from an indirect lateral injury, often results in displacement, dislocation, or avulsion rather than true fracture. The physical elasticity and flexible attachments of the nasal cartilage allow for the significant absorption and dissipation of energy, thus preventing considerable injury from a greater amount of force than the bony structure would tolerate. The nasal septum, however, is less apt to avoid injury given its rigid osteochondral junctions, which include the perpendicular plate of the ethmoid bone and the vomer anteriorly and its relatively weak association with the maxillary crest. As such, a higher incidence of true fracture can be found with the cartilaginous septum as a result of trauma to the midface, usually with a vertical orientation caudally and a horizontal orientation posteriorly.
In children, the nasal bones retain their elasticity with stability resulting from development and immature pneumatization. These factors, combined with a child’s proportionally smaller nasal bones and proportionally larger cartilaginous structures, produce a greater tendency for cartilaginous injury to occur. However, in most cases of nasal trauma, the nasal cartilage fractures without significant displacement and, given the inherent flexibility of a child’s nose, often returns to its anatomic position.
Classification
The classification of nasal injuries can be separated into two groups: those created by lateral or oblique impact and those created by frontal impact.
Lateral injury, the more common variety given the absence of structural support on either side of the nasal pyramid, can be divided into three planes, with the extent of involvement dependent on the force of impact. Injury in the first plane results only in fracture of the ipsilateral nasal bone, by far the most common occurrence, which usually results in a visible depression of the bony surface two thirds of the way down its slope. With greater force, injury in the second plane would also involve the contralateral nasal bone and septum. In the third plane, enough force would be provided to fracture the frontal process of the maxilla and the lacrimal bone, possibly resulting in fragmentation, a total dislocation of the nasal architecture, or even injury to the lacrimal apparatus.
With lateral injuries, fractures of the nasal septum usually extend posteriorly into the perpendicular plate of the ethmoid bone, but without extension to the cribriform plate.
Frontal injuries generally require a greater amount of force and are divided into three planes as well. The first plane is limited to the nasal tip and does not extend beyond an anatomic line separating the lower part of the nasal bones from the nasal spine. With most of the impact absorbed by the nasal cartilage, injury usually involves avulsion of the upper lateral cartilages. Posterior dislocation of the septal and alar cartilages is also possible, but less likely. Injury in the second plane includes the nasal spine as well as the nasal dorsum and the nasal septum. Injuries in this plane produce a flattening and splaying of the nasal bones with deviation of the septum, overriding segmentation, mucosal tearing, and fracture of the nasal spine. Injury in plane 3 requires a substantial force of impact and may involve fractures of the orbit or extend to structures within the cranial vault. The nasal bones are often comminuted and associated with fractures of the frontal process of the maxilla, lacrimal, and ethmoid bones, and occasionally the cribriform plate. Fracture and dislocation of the nasal septum are severe, with collapse of the dorsal plane and telescoping of the septal fragments.
The nasal septum may be involved in approximately 20% of all traumatic fractures of the nose. A substantially greater impact, however, whether frontal, lateral or oblique, consistently produces a C-type fracture of the septum just posterior to the nasal spine and extending posteriorly and superiorly into the perpendicular plate. It then changes direction anteriorly, ending just before and below the cribriform plate, along the posterosuperior aspect of the nasal bones. This finding can be demonstrated on physical exam by noting displacement of the caudal septum to one side and deviation of the posterior septum to the other.
Anatomy
The structure of the nasal pyramid projects anteriorly from the midface, attached to the facial skeleton at its base superiorly. From the apex or nasal tip, the columella projects inferoposteriorly toward the center of the superior lip, adjacent on either side to the nares. Encompassing the border of the nares are the alae of the nose superiorly and laterally, and the floor of the nose inferiorly. At the posterior aspect of the base of the nose is the piriform aperture, bordered superiorly and laterally by the frontal processes of the maxilla and the nasal bones. The inferior portion of the cartilaginous nose, otherwise considered the base of the nose, includes the lobule, which consists of the lower lateral cartilages, the tip, the alae, and the columella. In the midline, the posterior aspect of the medial crura of the lower lateral cartilages articulates with the caudal membranous septum. Anteriorly, the medial crura are enclosed within the columella. The lateral crura of the lower lateral cartilages project superiorly to overlap the inferior aspect of the upper lateral cartilages in the midline. Laterally, these crura loosely attach to the piriform aperture. The superior portion of the cartilaginous nose includes the two upper lateral cartilages and the quadrilateral cartilage of the septum, all of which are invested by a common perichondrial sheath. Laterally, the superior aspects of the upper lateral cartilages are also loosely attached to the piriform aperture.
Superior to the nasal base is the bony vault of the nose, which is bound by the frontal processes of the maxilla, the nasal bones, and the alveolar process. Through the midline of this vault runs the anterior nasal spine inferiorly and the perpendicular plate of the ethmoid bone superiorly. At the superior aspect of where the nasal bones meet the frontal bone is the nasion, which is the midline portion of the nasofrontal suture. At the inferior aspect of where the nasal bones meet the nasal cartilages is the rhinion, which is also in the midline. The septum of the nose includes the quadrilateral cartilage and the anterior nasal spine anteroinferiorly, and the perpendicular plate of the ethmoid bone, the sphenoid crest, the vomer, and the maxillary crest posterosuperiorly. At the roof of the nose within the nasal cavity is the cribriform plate, and at the posterior aspect of this roof is the choana, through which the nasal cavities and the nasopharynx communicate. At the floor of the nasal cavity are the palatine process of the maxilla and the horizontal process of the palatine bone, with the medial pterygoid plates located laterally on either side.
The nasal turbinates are found on the medial aspects of the nasal cavities. The inferior turbinate lies superior to the inferior meatus and is the largest of the three. Inferior to the turbinate within the inferior meatus is the opening of the ipsilateral nasolacrimal duct. The middle meatus lies between the inferior and middle turbinates and accepts drainage from the frontal sinus, the maxillary sinus, and the anterior ethmoid air cells. The superior turbinate lies above the superior meatus, which drains the posterior ethmoid air cells. Posterosuperior to this structure lays a sphenoethmoid recess on either side of the anterior aspect of the sphenoid sinus.
The external blood supply of the nose includes indirect contributions from both the external and the internal carotid arteries. From the external carotid artery, branches of the facial artery supply the inferior aspects of the nose and include the superior labial and lateral nasal arteries. These branches join with the dorsal nasal artery, a terminal point for the ophthalmic artery from the internal carotid artery. The internal blood supply of the nasal pyramid and superior portion of the nasal cavity also include an indirect contribution from the internal carotid artery by way of the anterior and posterior ethmoid branches of the ophthalmic artery. The maxillary artery off of the external carotid artery provides most of the blood supply to the nasal cavity by way of the sphenopalatine artery. At the posterior aspect of the middle turbinate, the sphenopalatine artery splits into the posterolateral nasal and septal arteries, the septal branches of which communicate anteriorly with the anterior ethmoid arteries—an important anastomosis between the external and internal arterial systems.
