Pressure injection demonstrates points of weakness in the posterior nasal arteries.

Objective: To test the hypothesis that potential sites of weakness within normal nasal arteries, when stressed, contribute to the mechanism of epistaxis, we 'stress-tested' nasal arteries in unfixed cadaveric heads, using pressure injection of feeding arteries.
Materials and Methods: Indian ink with latex was injected into maxillary arteries under high pressure (620 mmHg). Stepwise dissection was carried out and areas showing ink leakage were examined. Control heads were injected at standard embalming pressures (375 mmHg).
Results: Ink leakage was found in all heads injected at higher pressure, and was restricted to the nasal mucosa. Histological examination of leakage points demonstrated vessel disruption consistent with dissecting aneurysm formation.
Discussion: Results showed that high pressure injection caused leakage from arteries in the posterior nose; the distribution of leakage points was consistent with many clinical investigations. The lesions produced were comparable with our best histopathological model of epistaxis, i.e. dissecting aneurysm formation. This suggests that pre-existing weaknesses in the arterial configuration may exist.